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Chem105 - BYU Final

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Are reactions chemical or physical properties?

chemical

Is tarnishing/rusting a chemical or physical property?

chemical

What is the sign of ∆G for the following processes? Remember, spontaneous reactions occur without being driven by an external source of energy. Hot soup gets cold

negative

What is the sign of ∆G for the following processes? Remember, spontaneous reactions occur without being driven by an external source of energy. Muffins rising in the oven

negative

What is the sign of ∆G for the following processes? Remember, spontaneous reactions occur without being driven by an external source of energy. Photosynthesis

negative

What is the sign of ∆G for the following processes? Remember, spontaneous reactions occur without being driven by an external source of energy. Salt dissolves in water

negative

What is the sign of ∆G for the following processes? Remember, spontaneous reactions occur without being driven by an external source of energy. Water vapor condenses on the sides of a glass of root beer

negative

What is the sign of ∆G for the following processes? Remember, spontaneous reactions occur without being driven by an external source of energy. Wood burns in air after being ignited

negative

What is Gas?

no defined shape or volume

Joseph Von Fraunhofer

noticed that the sun's spectral lines contained 574 dark lines and was not a continuous spectrum

When 4.00 g NH4NO3 (80.04g/mol) - the active ingredient in some chemical cold packs - is dissolved in 96.0 g H2O, the temperature of the resulting solution is 3.07°C colder than the water and ammonium nitrate were before they were mixed together. What is the value of ∆H for the following dissolution process? NH4NO3(s) -> NH4NO3(aq) ∆H = ? Hint: Because the amount of ammonium nitrate dissolved is relatively small, you can assume that the heat capacity of the final solution is close to that of pure water (4.184 J/g°C).

nrxnΔHrxn = - msol Csol ΔTsol = (.05moles)(ΔHrxn)= - (100g)(4.184J/g°C)(-3.07°C) = ΔHrxn = 25689 J/mol ~ 25.7 kJ/mol

Is conductivity a chemical or physical property?

physical

Is density a chemical or physical property?

physical

Is malleability a chemical or physical property?

physical

Is melting point a chemical or physical property?

physical

Sigdigs in regards to math

+/- = round to nearest decimal, x// = round to lest number of sigdigs

What is the Law of Definite proportions?

"every chemical compound contains fixed proportions of its elements. Joseph Proust (you can add 1 or 2 atoms, but not 1.5)

Which subshell corresponds to each of the following sets of quantum numbers? n = 2, l = 1 n = 5, l = 3 n = 3, l = 2 n = 4, l = 3

2p 5f 3d 4f

Ammonia, alcohols, and water are the main ingredients of Windex. What is the dominant intermolecular force in Windex?

Hydrogen Bonding

dominant intermolecular forces for Vinegar (a mixture of acetic acid and water)

Hydrogen Bonding

How many neutrons are in 10. g of fluorine-19, the only stable isotope of fluorine?

10g x (1amu/ 1.67x10-24g) x (1 atom F/19 amu) x (10 neutrons/1 atom F = 3x1024 neutrons

How many protons, neutrons, and electrons are in 23Na and what is the mass number?

11 protons, 12 neutrons, 11 electrons and 23

Calculate with correct SN and SI: 77.3 g + 41.7 g =

119.0g = 0.1190 kg

Which isotope in each of the following pairs of stable isotopes is more abundant? 10B or 11B

11B is more abundant, because the atomic mass of Boron is closer to 11amu than it is to 10amu. (10.811amu).

What is the Law of Multiple proportions?

"a compound forms from its elements through the combination of atoms of unlike elements in small whole-number ratios" John Dalton - evidence of atoms

What is the law of conservation of energy?

"Energy can't be created or destroyed" French scientist Lavoisier burned things in a closed container and observed that the mass didn't change. Disproved the existence of phlogiston.

What is the Law of Conservation of mass?

"Matter can't be created or destroyed"

The combustion of 40.5 mg of a compound extracted from the bark of the sassafras tree and known to contain C, H, and O produces 110.0 mg CO2 and 22.5 mg H2O. The molar mass of the compound is 162 g/mol. What are its empirical and molecular formulas?

(.110g CO2x1mol CO2 x 1molC x 12.011gC) / (44.009g CO2x1mol CO2x1molC) = 0.03002gC/12.011 = 0.002499molC/0.000497656 = 5.022~5 (0.0225g H2O x 1 mol H2O x 2molH x 1.0079gH) / (18.015g H2O x 1mol H2O x 1molH) = 0.002518gH/1.0079 = 0.002498molH/0.000497656 = 5.019~5 0.007962gO/15.999 = 0.000497656molO/0.000497656 = 1~1 Empirical Formula: C5H5O (molar mass is 81g) Molecular Formula is double: C10H10O2

0.225g of Caproic acid (an organic molecule that smells like dirty socks) is analyzed by combustion analysis. 0.512 g of CO2 and 0.209 g of H2O are produced. The molar mass of the compound is 116 g/mol. What are its empirical and molecular formulas?

(.512g CO2 x 1 mol CO2 x 1molC x 12.011gC) / (44.009g CO2 x 1mol CO2 x 1 molC) = 0.1397gC/12.011 = 0.01163molC / 0.00387 = 3.005~3 (0.209g H2O x 1mol H2O x 2 molH x 1.0079gH)/ (18.015g H2O x 1mol H2O x 1molH) = 0.02339gH/1.0079 = 0.0232molH / 0.00387 = 5.995~6 0.06191gO/15.999 = 0.00387molO / 0.00387 = 1~1 Empirical Formula: C3H6O (which has a molar mass of 58) Molecular Formula is double: C6H12O2

0.811g of KClO3 is decomposed as follows: 2KClO3(s) → 2KCl(s) + 3O2(g) The O2 is collected over water at 28 ºC and 765 torr. What is the volume of water displaced in this measurement, assuming the reaction goes to completion?

(.811gKClO3 x 1 mol KClO3 x 3 mol O2) / (1225g KClO3 x 2 mol KClO3) = 0.00993 mol O2 V = nRT/P = (0.00993)(0.08206)(301) / (736.65/760) = 0.253 L

How many protons would be in 1.3 x 10^6?

(1.3 x 106) x 82 (number of protons per atom) = 10.7 x 107 protons

Nitrogen triiodide (NI3) is a contact explosive, meaning it explodes literally at the touch of a feather producing a loud sharp snap and a purple cloud of iodine as follows: _2__NI3(s) → __1_N2(g) + _3__I2(s) If you want to produce 10.0 L of nitrogen gas, how much NI3 must you start with? The density of N2 gas is 1.25 g/L.

(10L N2 x 1.25 gN2 x 1mol N2 x 2mol NI3 x 394.7g NI3) / (1L N2 x 28g N2 x 1 mol N2 x 1 mol NI3) = 352g NI3

Use the following reaction (assume excess carbon monoxide): Fe2O3(s) + 3CO → 2Fe(s) + 3CO2(g). If you start with 16g of iron(III) oxide and produce 8.4g of iron metal, what is the % yield? If you wanted to produce 100. g of iron metal and you knew the % yield of the reaction was typically 80.%, how much iron(III) oxide would you need to start with?

(16g Fe2O3 x 2 mol Fe x 55.85 g Fe) / (159.7g Fe2O3) = 11.2gFe -- 8.4/11.2 = 75% yield 100/.8 = 125 (125g Fe x 159.7g Fe2O3) / (55.85gFe x 2 molFe) = 178.7 g Fe2O3

A single gold atom has a mass of 197.0 amu. How many gold atoms are in a cube of gold that is 10.0 mm on each side (about the size of a sugar cube) if the density of gold is 19.3 g/cm3? (1 amu = 1.66053892x10-24g)

(1cm = 10.0 mm) -- D=m/v -- 19.3 g/cm3 = m/ 1 cm3 = 19.3 grams -- (1 amu = 1.66053892x10-24g) --197 amu x 1.66053892x10-24g =3.27126167 x 10-22 g -- 19.3/3.27126167 x 10-22 g = 5.90 x 1022 gold atoms

If a single carbon atom has a diameter of 1.54 Å (10 Å = 1 nm), how many carbon atoms could fit side-by-side along the width of an exclamation point line drawn by your pencil (assuming your pencil uses "lead" that is 0.20 mm wide)?

(1mm = 1000000 nm) -- 0.20 mm x 1000000 = 200000 nm -- (10 Å = 1 nm) -- 200000 nm x 10 = 2000000 Å -- 20000000 Å/1.54 Å = 1298701.299 carbon atoms -- 1.3 x 106 carbon atoms

If you had 1 mole of M&M's, how big would the box need to be to hold all of them? Assume the volume of a single M&M candy is about 2.2 cm3 , and calculate the volume of the box in km3.

(2.2)(6.022 x 1023) = 1.3x1024cm3 1.3x1024cm3 x (1m3/1000000cm3) x (1km3/1000000000m3) = 1.3x109 km3

Use the ∆Gºf values in Appendix 4 of your book to calculate ∆Grxn for the combustion of diamond and determine whether it is spontaneous under standard conditions. C(s) + O2(g) → CO2(g)

(2.85kJ/mol) + (0) → (-394.4 kJ/mol) ∆Grxn^°=∑n∆Gf°products - ∑n∆Gf° reactants = [(394.4 kJ/mol)] - [(92.85 kJ/mol) + (0)] = -397.25 kJ/mol - spontaneous

Chemical analyses conducted by the first Mars rover robotic vehicle in its 1997 mission produced the magnesium isotope data shown in the table below. Is the average atomic mass of magnesium in this Martian sample the same as on Earth (24.305 amu)?

(23.9850)(.7870) + (24.9858)(.1013) + (25.9826)(.1117) = 24.310 amu. The average atomic mass of magnesium in the Martian sample is not quite the same as on Earth. 24.310amu does not equal 24.305amu.

Pound for pound, more sulfuric acid is produced in the world than any other chemical. The formation of H2SO4 is a three-step process: S(s) + O2(g) → SO2(g) 2SO2(g) + O2(g) → 2SO3(g) SO3(g) + H2O(l) → H2SO4(aq) If you started with 25.0 kg of sulfur, excess water, and an unlimited supply of oxygen, how many kg of sulfuric acid will be formed if the reaction goes to 100% completion? In real life, the formation of sulfuric acid is an equilibrium process in which the reaction does not go to completion. If you obtain 54.36 kg of sulfuric acid, what is the percent yield?

(25kgS x 1000gS x 2mol SO3 x 98g H2SO4) / 32gS x 2mol SO2 x 600g H2SO4) = 76.56 kg H2SO4 54.36/76.56 = 71% yield

Naturally occurring sulfur consists of four isotopes: 32S (31.9721 amu, 95.04%); 33S (32.9715 amu, 0.75%); 34S (33.9679 amu, 4.20%); and 36S (35.9671 amu, 0.01%). Use this information to calculate the average atomic mass of sulfur.

(32S)(%) + (33S)(%) + (34S)(%) + (36S)(%) (31.9721)(.9504) + (32.9715)(.0075) + (33.9679)(.042) + (35.9671)(.0001) = 32.3 amu

The first step in the industrial production of nitric acid is reacting ammonia with oxygen according to the unbalanced equation: 4NH3(g) + 5O2(g) → 4NO(g) + 6H2O(g) How many liters of NH3(g) at 850.ºC and 5.00 atm are required to react with 32.0 g of O2?

(32g O2 x 1 mol O2 x 4 mol NH3) / (32g O2 x 5 mol O2) = 0.8 mol NH3 V = nRT/P = (.8)(.08206)(1123)/5 = 14.7 L NH3

Commercial manufacturers produce nitric acid (HNO3) by the Ostwald process. The process requires three steps: 4NH3(g) + 5O2(g) → 4NO(g) + 6H2O(g) 2NO(g) + O2(g) → 2NO2(g) 3NO2(g) + H2O (l) → 2HNO3(aq) + NO (g) Begin with 37.0 kg of ammonia (NH3) and an unlimited supply of oxygen and water. How many kilograms of oxygen gas will be consumed in the process? How many kilograms of nitric acid will be produced? (i.e., the theoretical yield) If the overall process normally has a percent yield of 83.0%, how many kilograms of nitric acid will actually be produced?

(37 kg NH3 x 1000g NH3 x 1 mol NH3 x 5 mol O2 x 32 g O2) / (17g NH3 x 4 mol NH3 x 1000g O2) = 87 kg O2 (37 kg NH3 x 1000g NH3 x 1 mol NH3 x 4 mol NO x 32 g O2) / (17g NH3 x 4 mol NH3 x 2 mol NO x 1000g O2) = 34.8 kg O + 87 = 121.8 kg O2 used (37 kg NH3 x 1000g NH3 x 1 mol NH3 x 4 mol NO x 2 mol NO2 x 2 mol HNO3 x 63g HNO3) / (17g NH3 x 4 mol NH3 x 2 mol NO x 3 mol NO2 x 1000g HNO3) = 91.4 kg HNO .83 x 91.4 = 75.86 kg

Combustion analysis reveals that a certain organic compound with a molar mass of 62.1 g/mol is 38.7% C, 9.7% H, and 51.6% O by mass. What are its empirical and molecular formulas?

(38.7gC x 1molC)/12.011 = 3.222molC /3.222 = 1~1 (9.7gHx1molH)/1.0079 = 9.624molH /3.222 = 2.987~3 (51.6gOx1molO)/15.999 = 3.225molO /3.222 =1.001~1 Empirical Formula: CH3O (which has a molar mass of 31) Molecular Formula is double: C2H6O2

Potassium chlorate, KClO3, is used in the oxygen supply systems of aircrafts, submarines, and space stations because heating KClO3 in the presence of an MnO catalyst causes it to decompose and produce O2 as follows: __2_ KClO3(s) → _2__KCl(s) + _3__O2(g). KClO3 is also often used to prepare small amounts of O2 on-the-spot in high school chemistry labs where keeping a full tank of oxygen is impractical. How many grams of O2 can be prepared from 4.50 g of KClO3?

(4.5g x 3molKClO3 x 32gO2)/(1225gKClO3 x 2molO2) = 1.76g O2

Baking soda (NaHCO3) is produced on an industrial scale by the Solvay process. A key reaction in the process is NaCl(aq) + NH3(aq) + CO2(aq) + H2O(ℓ) → NaHCO3(s) + NH4Cl(aq) Suppose a reaction vessel initially contains 58.5 kg NaCl, 18.8 kg NH3, and excess CO2 and H2O. If 66 kg NaHCO3 is produced, what is the percent yield?

(58.5kgNaCl x 1000gN x 1 mol NaCl x 84g NaHCO3 x 1 kg NaHCO3) / (58.5g NaCl x 1000g NaHCO3) = 83.57 kg NaHCO3 66/83.57 = 79%

Calculate the atomic weight of nickel to the correct number of significant figures using the following data: 58Ni, 68.075%, 57.9353429 amu 60Ni, 26.221%, 59.9307864 amu 61Ni, 1.1399%, 60.9310560 amu 62Ni, 3.637%, 61.9283451 amu 64Ni, 0.9271%, 63.9279660 amu

(58Ni)(%) + (60Ni)(%) + (61Ni)(%) + (62Ni)(%) + (64Ni)(%) (57.935)(.68075) + (59.931)(.26221) + (60.93)(.011399) + (61.93)(.03637) + (63.928)(.009271) = 58.69 amu

Prolonged exposure to ultraviolet radiation in tanning booths significantly increases the risk of skin cancer. What is the energy of a photon of UV light with a wavelength of 3.00 × 10-7 m?

(6.626 x 10-34J-s) (2.998 x 108m/s) = 1.99x10-25 / (3.00x10-7m) = 6.62 x 10-19J

Water in a leather flask or a porous clay pot can be cooled in hot climates by evaporating water from the surface of the container. Calculate what mass of water can be cooled from 35 ºC to 20. ºC via the evaporation of 60. g of water.

(60/18)(40.67 kJ/mol) = -mw(4.184J/gC)(-15C)(1kJ/1000J) = 2160g

In a manufacturing process, gas A reacts with gas B to form gas C according to the following equation. 3A + B → 2C If you react 7.00 L of gas A and 2.70 L of gas B, how many liters of gas C can you produce? If you isolated 3.14 g of g of gas C at STP from the reaction in part a, what is the molecular weight of C? Assume 100% yield.

(7LA x 2LC) / 3LA = 467 LC V = 467L n = PV/RT = (1)(467) / (0.08206)(273) = .208 molgasC 3.14g / .208 molgasC = 15.1 g/mol

Say the MO configuration of a particular molecule is [core](σ2s)2 (σ2s*)2 (π2p) 4 (σ2p) 2 (π2p*)3 (σ2p*)0 . What is the bond order? What is the HOMO and LUMO. Is the molecule paramagnetic or diamagnetic?

(8-5)=3(½) = 1.5, HOMO: (π2p*), LUMO: (σ2p*), Paramagnetic

In self-contained breathing devices used by first responders, potassium superoxide, KO2, reacts with exhaled carbon dioxide producing potassium carbonate and oxygen: __4_ KO2(s) + _4__ CO2 (g) → _2__ K2CO3(s) + _3__ O2 (g) How much O2 could be produced from 85 g KO2?

(85g KO2 x 3 mol O2) / (71.1g KO2 x 4 mol KO2) = 0.897 mol O2

Suppose pairs of balloons are filled with 10.0 g of the following pairs of gases. Which balloon in each pair has the greater number of molecules (or atoms in the case of Ar)? Explain how you know.CO2 or SO2

(CO2 has a greater number of molecules, because it has a smaller molecular mass so the denominator is smaller).

(NO has a greater number of molecules, because it has a smaller molecular mass so the denominator is smaller).

(O2 has a greater number of molecules, because it has a smaller molecular mass so the denominator is smaller).

What values of l correspond to the letters s, p, d, and f? Why do we use letters to denote the values of the angular momentum quantum number, l?

(l) = 0 - s, (l) = 1 - p, (l) = 2 - s (l) = 3 - f Letters are utilized to make it less confusing to read and identify orbitals.

You happen to drop exactly 10.0 mL of tap water (25.0°C) onto a hot iron skillet whose mass is 1.20 kg. All of the water is converted into steam at 100.0°C. What is the change in temperature of the skillet?

-(21.5mol)(25.19) ΔT Fe = (10g)(4.18)(100°C -25°C)+ (.556mol)(40700) = ΔT Fe = -47.5°C

Paramagnetic or diamagnetic: Br-

-- Diamagnetic

Paramagnetic or diamagnetic: Cl

-- paramagnetic

Astronomers have detected hydrogen atoms in interstellar space in the n = 732 excited state. Suppose an atom in that excited state undergoes a transition from n = 732 to n = 731. How much energy does the atom lose as a result of this transition? What is the wavelength of radiation corresponding to this transition? What kind of telescope would astronomers need to detect radiation of that wavelength? (Hint: It would not be a visible-light telescope.)

-1.11 x 10-26J, 1.78 x 1010nm, A long radio wave telescope

An expanding gas does 150.0 J of work on its surroundings at a constant pressure of 1.01 atm. If the gas initially occupied 68 mL, what is the final volume of the gas?

-1.48LatmJ= - (1.01atm) (Vf-0.068L) 1.466L = vf-0.068L = 1.53L

An unknown gas is pumped into a 2.15184 L container that is already filled with some O2. The unknown gas exerts a partial pressure of 2.30 atm. If the total pressure exerted by both gases is 11.2 atm, what is the mole fraction of the unknown gas?

.205

a. A common gem size used in wedding rings is about ½ carat. The white diamond in my wedding ring is 0.536 carats. Given that the density of white diamond (a pure form of carbon) is 3.50 g/cm3 and 1 carat = 200. mg, how many C atoms are in my ring? How many moles of C is this? The Cullinan diamond (3106.75 carats) is the largest gem quality rough white diamond ever found. How many diamonds like the one in part (a) could the Cullinan diamond have been used to make?

.536 carats x (200 mg/1carat) x (1g/1000mg) x (1 molC/12.011) x (6.022 x 1023atoms/1mole) = 5.37 x 1021 atoms or 0.0089 moles of C and (3106.75 carats/.536 carats) = 5.80 x 103 rings

A glass container with a volume of 5.00 L holds 0.120 g of Cl2 gas and 0.145 g of F2 gas at a total pressure of 1.80 atm. Determine the partial pressure of each of the gases.

.552 atm - CL2, 1.248 atm - F2

A gas mixture contains 7.0 g N2, 2.0 g H2, and 16.0 g CH4. What is the mole fraction of H2 in the mixture?

0.44

For both sigma and pi bonds, describe whether they occur in single, double, and triple bonds (& how many in each)

1 Sigma = Single Bond, 1 Sigma + 1 Pi = Double Bond, 1 Sigma + 2 Pi = Triple Bond

Which component in each of the following pair has the greater entropy? 1 gram of O2(g) or 1 gram of O3(g)

1 gram of O2(g)

Which component in each of the following pair has the greater entropy? 1 mole of O2(g) or 1 mole of O3(g)

1 mole of O3(g)

Which component in each of the following pair has the greater entropy? 1 mole of S2(g) or 1 mole of S8(s)

1 mole of S2 (g)

Which component in each of the following pair has the greater entropy? 1 mole of S2(g) or 1 mole of S8(g)

1 mole of S8(g)

State 3 factors that affect entropy change, how entropy changes with each, and why.

1. Phase of the substance - decreases from gas to liquid to solid, because it is more confined by its neighboring molecules as it increases in structure. 2. The number of particles/volume - Increases with increased particles. The entropy of a system is proportional to the number of its particles. 3. Temperature - the higher the temperature, the higher the entropy

Give examples of 3 everyday things that are quantized

1. Ranking at the Olympics 2. Stairs 3. Ladder

The price of gold in May was $1,228.40 per ounce (1 ounce = 28.35 g). A typical gold bar such as those shown here has a mass of 12.4 kg. How much would one of these bars of gold cost?

12.4 kg x (1000g/1kg) x (1oz./28.35g) x ($1228.40/1oz.) = $537,000.

Scientific Notation: 613ml + 582 ml =

1.20 x 10^3 ml

A synchrotron is a type of particle accelerator in which a ring of variable electric and magnetic fields accelerates particles (electrons, protons, etc.) to speeds nearing the speed of light. The largest synchrotron in the world is the Large Hadron Collider in Geneva, Switzerland where protons (mp = 1.6726x10-27 kg) can be accelerated to speeds of 0.999999991 c. A. What is the de Broglie wavelength of one of these protons? B. What is the wavelength of an electron (me = 9.109x10-31kg) moving at that same speed? (not considering relativistic effects) C. If the relative uncertainty in the velocity of a proton in the Large Hadron Collider is 3.0%, what is the uncertainty in its position? How does this uncertainty affect the ability of scientists to collide such a proton with an atom (diameter roughly on the order of Angstroms, or 1x10-10m) or another proton (charge radius about 0.9 fm) in the Large Hadron Collider?

1.32x10-15m or 1.32x10-6nm, 2.43 x 10-12m or 2.43 x 10-3nm, Δx = 3.51 x 10-15m It is easy to hit the atom, because the atom is so much wider than the uncertainty range. The uncertainty is almost 4x the radius of a proton, so its much harder to hit.

Scientific Notation: 25.34 cm ÷ 1.55x10-4 cm=

1.63 x 10^5

Calculate the pressure exerted by 5.00 mol of CO2 in a 1.00 L vessel at 300 K Assuming the gas behaves ideally and then Using the van der Waals equation. Explain any differences in the results.

123 atm, 66.75 atm, the IM forces and volume of the Co2 molecules skewed the results. However, in ideal gases, there are no IM forces and the volume of the particles of gas negligible

Which isotope in each of the following pairs of stable isotopes is more abundant? 14N or 15N

14N is more abundant, because the atomic mass of Nitrogen is closer to 14amu than it is to 15amu. (14.007amu).

How many protons, neutrons, and electrons are in 32Ge2- and what is the mass number?

16 protons, 16 neutrons, 18 electrons and 32

How many protons, neutrons, and electrons are in 37Cl and what is the mass number?

17 protons, 20 neutrons, 17 electrons and 37

The diameter of a US dime is 17.9mm, and the diameter of a silver atom is 2.88 A. How many silver atoms could be arranged side-to-side across the diameter of a dime? (10A = 1 nm).

17.9mm x (1m/1000mm) x (1nm/1x10^-9m) x (10 Å /1nm) x (1Ag atom / 2988 Å) = 6.22 x 10^7 Ag atoms

A 1-liter sample of seawater contains 19.4 g Cl- , 10.8 g Na+ , and 1.29 g Mg2+ How many moles of each ion are present?

19.4/35.5 = 0.547 mol Cl-, 10.8/23 = 0.47molNa+, 1.29/24.3g = 0.0531 Mg2+

The following reaction plays a key role in the destruction of ozone in the atmosphere: ½ Cl2(g) + O3(g) → ClO(g) + O2(g) The standard entropy change (∆S°rxn) is 19.9 J/(mol · K). Use the standard molar entropies (S°) in Appendix 4 to calculate the S° value of ClO(g).

19.9J/molK = [S°ClO + 205] - [.5(223) + 238.8] = 170.2 J/molK

Robbie Millikan my man

1910 Millikan oil drop, calculated the mass of the drops of oil and found the mass of the electron and the electron charge amount

Calculate with correct SN and SI: 387 pg ÷ 2x10-2 mL =

19350 pg/mL = 1.935x10^-11 kg/mL = 2x10^5 kg/m^3

Electron Configuration of Atomic number 15: P

1s22s22p63s23p3 = [Ne] 3s23p3

Electron Configuration of Atomic number 18: Ar

1s22s22p63s23p6 = [Ne] 3s23p6

Electron Configuration of Cu+:

1s22s22p63s23p63d10 = [Ar]3d10

Electron Configuration of Fe2+:

1s22s22p63s23p63d6 = [Ar]3d6

Electron Configuration of Atomic number 19: K

1s22s22p63s23p64s1 = [Ar]4s1

Electron Configuration of Atomic number 29: Cu

1s22s22p63s23p64s23d10 = [Ar]4s23d10

Electron Configuration of Br - :

1s22s22p63s23p64s23d104p4 = [Ar]4s23d104p4

Electron Configuration of Atomic number 22: Ti

1s22s22p63s23p64s23d2 = [Ar]4s23d2

Electron Configuration of Atomic number 24: Cr

1s22s22p63s23p64s23d5 = [Ar]4s23d5

Calculate with correct SN and SI: (2.76x103) (7.4x102 ) nL =

2.0x10^6 nL = 2.0 x 10^-3 L

Calculate the number of neutrons found in 2.13 mg of the non-fissionable isotope of uranium which has a mass number of 238.

2.13mg x (1/1000mg) x (1 molU/238g) x (6.022x1023 atoms/1molU) x (146 neutrons/1 atom) = 7.87 x 1020

Scientific Notation: 6.31x104 pm x 3.536 x 105 pm=

2.23 x 10^10 pm^2

Scientific Notation: 85 ng x 34 ng=

2.9 x 10^3 ng^2

Calculate with correct SN and SI: 21.7 cm x 9300 cm2 =

200000 cm^3 = .20m^3

Which isotope in each of the following pairs of stable isotopes is more abundant? 20Ne or 22Ne

20Ne is more abundant, because the atomic mass of Neon is closer to 20amu than it is to 22amu. (20.180amu).

Unlike most metals, gold occurs in nature as the pure element. Miners in California in 1849 searched for gold nuggets and gold dust in streambeds, where the denser gold could be easily separated from sand and gravel. However, larger deposits of gold are found in veins of rock and can be separated chemically in a two-step process: 1. 4 Au(s) + 8 NaCN(aq) + O2(g) + 2 H2O(ℓ) → 4 NaAu(CN)2(aq) + 4 NaOH(aq) 2. 2 NaAu(CN)2(aq) + Zn(s) → 2 Au(s) +Na2[Zn(CN)4](aq). If 23 kilograms of ore is 0.19% gold by mass, how much Zn is needed to react with the gold in the ore? Assume that both reactions are 100% efficient.

23 x .0019 = 0.0437 kg Au ~ 43.7g Au(43.7g Au x 4 mol NaAu(CN)2 x 65.38gZn) / (196.97gAu x 4 mol Au x 2 mol NaAu(CN)2) = 7.25gZn

Write the symbol of the most abundant isotope of sodium. How many neutrons does it contain?

23Na contains 12 neutrons.

The density of air at 25 ºC and 642 torr is 1.00 g/L. What is the molar mass of air?

28.9 g/mol

At an elevation where the boiling point of water is 93°C, 1.33 kg of water at 30°C absorbs 290.0 kJ from a mountain climber's stove. Is this amount of thermal energy sufficient to heat the water to its boiling point?

290kJ = - mw Cw ΔT w = 29000J = 1330g(4.18)(Tf-30°C) = Tf= 82.16°C so no

In rocket fuel (as in many of the balloons we blow up in class), hydrogen gas (H2) reacts with oxygen gas (O2) to form water vapor. Write a balanced reaction for the process. Suppose you have a mini rocket and access to 2.50 L of oxygen gas and 4.00 L of hydrogen gas. If you use up all of the gas possible blasting off your rocket, how many liters of water vapor did you produce (at the same temperature as the original mixture)? How many grams of water vapor did you produce, assuming it happened at STP?

2H2(g) + O2(g) -> 2H2O(g) = (4L H2 x 2L H2O) / 2L H2 = 4 L H2O PV = nRT = N = PV/RT = [(1atm)(4L)] / (0.08206)(273K) = 0.179 mol H2Ox 18g H2O= 3.21g H2O

A recipe for 1 cup of hollandaise sauce calls for 1/2 cup of butter, 1/4 cup of hot water, 4 egg yolks, and the juice of a medium-sized lemon. How many cups of sauce can be made from a pound (2 cups) of butter, a dozen eggs, 4 medium-sized lemons, and an unlimited supply of hot water? What is the limiting reactant, and what will you have left over if you make the maximum amount of hollandaise sauce possible?

3 cups of sauce can be made from a pound of butter, a dozen eggs, 4 medium-sozed lemons, and an unlimited supply of hot water, because the egg is the limiting reactant and it is limited to 3 cups. If you made the max amount of sauce, you would be left with a half cup of butter, no eggs, 1 lemon, and the unlimited supply of water.

Which of the following sets of quantum numbers (n, l, ml, ms) are actually possible? 3, 2, -2, ½ - 1, 1, 0, ½ - 1, 0, 1, -½ - 0, 0, 0, ½ - 2, 0, 3, -½

3, 2, -2, ½

Which of the following represents the largest amount of matter? 3.0 x 10-1 Mg, 4.5 x 102 mg, 1.0 x 107 µg, 2.0 x 108 ng, 2.5 x 1013

3.0 x 10-1 Mg

How many protons, neutrons, and electrons are in 81Tl1- and what is the mass number?

35 protons, 46 neutrons, 36 electrons

Which isotope in each of the following pairs of stable isotopes is more abundant? 35Cl or 37Cl

35Cl is more abundant, because the atomic mass of Neon is closer to 35amu than it is to 37amu. (35.453amu).

How many protons, neutrons, and electrons are in 89Ac and what is the mass number?

39 Protons, 50 neutrons, 39 electrons and 89

Chemical equation for when solutions of lead(II) nitrate and phosphoric acid react to produce solid lead(II) phosphate and a solution of nitric acid

3Pb(NO3)2(aq) + 2H3PO4(aq) -> Pb3(PO4)2(s) + 6HNO3(aq)

Scientific Notation: 4x10-3 mL - 2x10-5 mL=

4.0 x 10^-3 mL

Scientific Notation: 124mg+316mg =

4.40x10^2mg

Chemical equation for when aluminum and oxygen react to form aluminum oxide

4Al(s) +3O2(g) -> 2Al2O3(g)

Chemical equation for when ammonia gas and nitrogen monoxide gas react to produce nitrogen and water vapor

4NH3(g) + 6NO(g) -> 5N2(g) + 6H2O (g)

What type of orbital is designated by n = 4, l = 2, ml = 0, ms = ½ ?

Which of the following transitions in the hydrogen atom would result in the emission of a photon with the longest wavelength? How do you know? n = 1 to n = 2, n = 3 to n = 1, n = 2 to n = 1, n = 4 to n = 3, n = 1 to n = 4

4to3 - This transition would result in the emission with the longest wavelength, because the movement is closer to the nucleus (decreasing in value). It is also the farthest out of the options as well, meaning that there would be less energy, shorted frequency, and a longer wavelength going from 4 to 3.

How many protons, neutrons, and electrons are in 118Uua and what is the mass number?

50 protons, 68 neutrons, 50 electrons, and 118

Calculate with correct SN and SI: 123.4 Gm - 68.93 Gm =

54.50 Gm

How many protons, neutrons, and electrons are in 137Ba2+ and what is the mass number?

56 protons, 81 neutrons, 54 electrons, and 137

How many sig figs are in the following number? 0.0509200

What is the density (in g/L) of sulfur hexafluoride at 227 ºC and 2.00 atm of pressure?

7.12 g/c

Suppose 75 metric tons of coal that is 3.0% sulfur by mass is burned at a power plant. During combustion the sulfur is converted into SO2. Antipollution scrubbers installed in the smoke stacks of the power plant capture 3.9 metric tons of this SO2. How efficient are the scrubbers in capturing SO2? How many metric tons of SO2 escaped?

75x.03 = 225 tons S (2.25tonsS x 100kg x 10000g x 1molS x 1molSO2 x 64gSO2) / (32g x 1000gSO2 x 1000 kg) = 4.5 tons SO2 3.9/4.5 = .867 ~ 86.7% efficient 4.5-3.9 = .6 tons escaped

Benzene, a common solvent, is a covalent molecular compound which contains only carbon and hydrogen. Its simplest (empirical) formula is CH, and its molecular weight to 2 significant digits is 78 g/mol. What is its molecular formula?

78/13(molecular mass of CH), Mf: C6H6

Which isotope in each of the following pairs of stable isotopes is more abundant? 6Li or 7Li

7Li is more abundant, because the atomic mass of Lithium is closer to 7amu than it is to 6amu. (6.941amu).

Calculate with correct SN and SI: 8.1x10-1 µm -3.7x10-8 µm =

8.1 x 10^-1 µm = 8.1 x 10^-7 m

Although they are not too common, there are US one-dollar coins. These are the so-called "golden dollars" which bear the likeness of Sacagawea or past US presidents. The composition of these "golden" coins as given by the US government is 6.0% zinc, 3.5% manganese, 2.0% nickel, and 88.5% copper. How many atoms of manganese are there in a Sacagawea dollar coin that weighs 8.100 g?

8.10 x 0.35 = 0.2835gMn 0.2835gMn x (1molMn/54.938g) x (6.022 x 1023atoms/1molMn) = 3.1 x 1021atoms

Radon is a naturally occurring radioactive gas found in the ground and in building materials. It is easily inhaled and emits α particles when it decays. Cumulative radon exposure is a significant risk factor for lung cancer. Calculate the density of radon at 298 K and 1 atm of pressure. Are radon concentrations likely to be greater in the basement or on the top floor of a building?

9.08 g/c Density of radon is higher than that of air, meaning that it will sink and by at the basement rather than the top floor.

How many protons, neutrons, and electrons are in 238U and what is the mass number?

92 protons, 149 neutrons, 92 electrons, and 238

Give the percent composition (by mass) for each of the hydrocarbons below. (Unless otherwise specified, assume percent composition is always the mass %.) Which two have the same percent composition? C6H6, C2H4, C3H8, C6H12

92.3% Carbon 7.7% Hydrogen, 85.7% Carbon 14.3% Hydrogen, 81.8.3% Carbon 18.2% Hydrogen, 85.7% Carbon 14.3% Hydrogen

What is a photon?

A photon, also known as a light quantum, is a particle of light structured in a minute bundle (or quantum) of electromagnetic (or light) energy. It is the basic unit of all light, always moving and, in a vacuum, travel at the constant speed of light (2.998 x 108 m/s).

What is a calorimeter?

A container/apparatus in which to do the calorimetry.

How does a hypothesis become a theory?

A hypothesis becomes a theory when there are several experiments which prove its validity. Once it is out of the first revision stage, it moves through a pattern of theory to experiments to second revision, until there is a final product theory which is supported by many different sources.

What is a node?

A node is an area within an atom where there is zero probability of finding an electron of a certain energy.

How does a hypothesis differ from a scientific theory?

A scientific hypothesis is a statement or prediction which is testable, however scientific theory is a hypothesis which is supported by many different sources through numerous experiments. Scientific theories are concise and well-tested, explaining why a natural phenomenon is observed or why a theory is true.

What does it mean for a reaction to happen 'spontaneously'?

A spontaneous reaction occurs when a process releases free energy and moves closer to an equilibrium thermodynamic energy state.

What is a bomb calorimeter?

A strong/sturdy calorimeter

A typical microwave oven operates at 2.45 GHz. A. Calculate the wavelength of this electromagnetic radiation. B. How many wavelengths does it take for the wave to travel the length of a 30.5cm wide microwave and back? C. How many nodes occur for the wave inside the microwave? Drawing a picture may be helpful.

A. λ =(c/v)=(2.998x108m/s) / (2.45x102) = 0.122 m x (100cm/1m) = 12.2 cm = 0.122 m B. 30.5cm x 2 = 61 cm / 12.2 (cm per λ) = 5 wavelengths C. 4 nodes could occur for the wave inside the microwave.

What is accuracy?

Accuracy: How close to the true value a set of measurements are.

What orbitals are degenerate in a hydrogen atom?

All orbitals with the same quantum number are degenerate in a hydrogen atom.

Another particularly interesting exception to the trend in 1st ionization energy is found by comparing nitrogen and oxygen. The 1st IE is higher for N than for O, even though O has 1 more proton in its nucleus. Offer an explanation. HINT: it may be helpful to look at the valence electron diagrams for N and O.

Although it would be easy to assume that it is easier to remove electrons from O, nitrogen is ½ full and it would rather not break that ½ full state. Oxygen, on the other hand, has some electron repulsion which makes it easier to remove the electrons.

In principle, we could use the more familiar unit dozen in place of the mole when expressing the quantities of particles (atoms, ions, or molecules). What would be the disadvantage in doing so?

Although the term "dozen" is regularly utilized as a measurement in society, it is a term which is symbolic for a small amount. A mole is an extremely large amount, meaning that it would be even more confusing to describe it in smaller chunks. It would just mean memorizing more numbers.

Which elements below form monatomic ions with a charge of 3+?

Aluminum

185grams of iron (II) oxide were reacted with 38.0 grams of aluminum as follows: 3 FeO(s) + 2 Al(s) → Al2O3(s) + 3 Fe(g) What was the limiting reactant? How many grams of total product (Al2O3 + Fe) formed if the reaction goes to completion? The total mass of the reactants is 223 grams. However, this is not the total mass of the products. Why not? If the actual yield of the iron is 105.0 grams, what is the percent yield of iron?

Aluminum (185gFeO x 102g N2O3) / (71.85gFeO x 3 molFeO) = 87.54g Al2O3 (38gAl x 102g Al2O3) / (27gAl x 2molAl) = 71.8g Al2O3 (38g Al x 3molFe x 88.85Fe) / (27gAl x 2 mol Al) = 118g Fe (38gAl x 102g Al2O3) / (27gAl x 2molAl) = 71.8g Al2O3 Total = 189.8g Iron(II) Oxide is unique in that it doesn't react completely so some remains after the reaction. 105/118 = 89% yield

What is an isotope?

An isotope is any form of an element which differs in number of neutrons causing its atomic mass to vary from the average atomic mass. Different isotopes of the same element will have nearly identical chemical behavior and the same atomic number, but may have different physical properties

When is an electron in an excited state?

Any level besides the ground level

Arrange the following atoms and ions in order from smallest to largest radius. Sr, Kr, Br, Rb, Ar

Ar, Kr, Br, Sr, Rb

Predict whether the entropy of the system increases or decreases in the following reaction: N2(g) + O2(g) → 2NO(g)

Around zero (neutral)

Why do we use Cp (heat capacity of an object) instead of specific heat or molar heat capacity to describe the heat capacity of the calorimeter?

As an object with a defined mass so multiplying by grams or converting to moles isn't practical because that value is always constant.

How is the rate of effusion of a gas related to its molar mass, rms speed, and temperature?

As the molar mass goes up, the speed decreases. As the room-mean-square-speed increases, then rate of effusion also increases. As the temperature increases, the rate of effusion also increases.

Describe how the charges of the monatomic ions that elements form change as group number increases in a particular row of the periodic table and how ion charges change as the row number increases in a particular group.

As you move closer to the Noble gases (as the group number in a particular row increases), the elements will have an increasing amount of electrons on their outer shells, so there is an increasing attraction between negatively charged electrons and the positively charged nucleus. As they increase in electrons moving from left to right, there is an increasingly positive charge until group 14, where it turns negative because the elements are so close to a full outer shell of electrons. Ionization energy decreases moving from top to bottom (as row number increases), because the number of electrons on the outermost shell on elements increases. More electron shells are added moving downwards, so the outer shell becomes increasingly distance from the nucleus.

Why do atoms form bonds?

Atoms form bonds to maximize stability (it makes outer electron shells more stable). Bonding also allows for the primal low-energy state to be obtained for an atom.

Suppose you are at a track where 7 joggers are doing laps. Their speeds are (in mph) 5, 5, 4, 3, 7, 8, and 9 mph. Calculate their average speed, then calculate their RMS speed (use 3 sig figs).

Average speed: 5.86 mph sqr. root of (269/7) = 6.20 mph - RMS speed

Two inorganic blue pigments are Han blue (BaCuSi4O10) and Egyptian blue (CaCuSi4O10). Which has a higher molar mass and by how much (include 4 significant figures)? If you had a 10g chunk of each, which sample could have more Cu atoms and how many more?

BaCuSi4O10, Ba + Cu + 4(Si) + 10(O) 137.328 + 63.546 + 4(28.086) + 10(15.9994) = 473.21 g/mol CaCuSi4O10, Ca + Cu + 4(Si) + 10(O) 40.078 + 63.546 + 4(28.086) + 10(15.9994) = 375.96 g/mol Han blue has a higher molar mass. 473.21 g/mol - 375.96 g/mol = 97.25g Han Blue: 10g BaCuSi4O10 x (1mol BaCuSi4O10/473.21g) x (1molCu/1mol BaCuSi4O10) x (6.022 x 1023atoms/1molCu) = 1.27x1022 Cu atoms. Egyptian Blue: 10g CaCuSi4O10 x (1mol CaCuSi4O10/375.96g) x (1molCu/1mol CaCuSi4O10) x (6.022 x 1023atoms/1molCu) = 1.60x1022 Cu atoms. Egyptian Blue would contain more. 1.60x1022 Cu atoms - 1.27x1022 Cu atoms = 3.32x1021 Cu atoms

Determine the molecular geometry of the following molecules using VSEPR and estimate the bond angles involved. For neutral molecules, state whether the molecule is polar or non-polar. BeF2, XeF2, ClO3-, BrF3

BeF2 Linear non-polar 180 degrees, XeF2 Linear non-polar 180 degrees, ClO3- Trigonal pyramidal polar < 109.5 degrees, BrF3 T-shaped polar <90 degrees

Explain Hess's Law (in your own words) and describe why/how it is so useful.

Because enthalpy is a state function, it can take any path it wants to reach its final products. Meaning that the energy change will equal the sum of the energy changes of its parts. It is helpful, because it allows us to determine the enthalpies of non elemental compounds (unstable intermediates)

What is blackbody radiation?

Blackbody radiation is the thermal electromagnetic radiation surrounding or within an object in thermodynamic equilibrium and is emitted by a blackbody/object.

Describe the strengths & limitations of Molecular Orbital Theory with regards to calculating bond energies, calculating bond order, understanding bond order, understanding magnetic properties, predicting molecular geometry.

Bond energies: It is possible, but it is complicated (requiring computerization). calculating bond order: It is very good. understanding magnetic properties: It is very good. predicting molecular geometry: It is not very good.

What is a chemical bond?

Bonds are an electrostatic attraction between positively charged protons and negatively charged electrons. These attractions bring two atoms, which are close and attracted to one another, together to form substances, share electrons, or transfer electrons.

Charcoal (C) and propane (C3H8) are used as fuel in backyard grills. Write balanced chemical equations for the complete combustion reactions of C and C3H8. How many grams of carbon dioxide are produced from burning 500.0 grams of each of the two fuels?

C + O2 -> CO2 C3H8 + 5O2 -> 3CO2 + 4H2O (500gC x 1molC x 1molCO2 x 44gCO2) / (12gC x 1molC x 1molCO2) = 1833g CO2 (500gC3H8 x 1molC3H8 x 3molCO2 x 44gCO2) / (44gC3H8 x 1molC3H8 x 1molCO2) = 1500g CO2

Calculate ∆H° for the reaction C2H4(g) + 6F2(g) = 2CF4(g) + 4HF(g) using the information below. H2(g) + F2(g) = 2HF(g) ∆H° = -537.0 kJ, C(s) + 2F2(g) = CF4(g) ∆H° = -680.0 kJ, 2C(s) + 2H2(g) = C2H4(g) ∆H° = 52.3 kJ

C2H4 -> 2C+ 2H2 - ∆H = -52.3 kJ 2C+ 2F2 -> 2CF4 - ∆H = -1360 kJ 2H2 + 2F2 -> 4HF - ∆H = -1074 kJ C2H4 + 6F2 -> 2CF4 + 4HF - ∆Hrxn = -2486.3 kJ

Calculate ∆H° for the combustion of ethanol (C2H5OH) to form carbon dioxide and water using the heats of formation below. ∆ H°fC2H5OH(l) = -277.7 kJ/mol ∆ H°fCO2(g) = -393.5 kJ/mol ∆ H°f H2O(l) = -285.8 kJ/mol

C2H5OH + 3O2-> 2CO2 + 3H2O ∆Hrxn = [2(-393.5kJ/mol) + 3(-258.8kJ/mol)] - [1(-2772 kJ/mol) + 3(0)] ∆Hrxn = -1367.2kJ

Chemical equation for when liquid ethanol reacts with oxygen to form carbon dioxide and water vapor

C2H6O(l) + 3O2(g) -> 2CO2(g) +3H2O(g)

Chemical equation for when pentane gas reacts with oxygen to form carbon dioxide and water vapor

C5H12(g) + 8O2(g) -> 5CO2(g) + 6H2O(g)

The 3-centimeter band is a portion of the radio spectrum that is allocated to amateur radio and amateur satellite enthusiasts. What is the frequency of electromagnetic radiation with a wavelength of 3.00 cm? How does this compare to the 60 Hz frequency of the oscillations of alternating current (AC) from our electrical power grid?

C= λv ~ V= (c/λ) (2.998x108m/s)/0.003 m = 1.00 x 1010Hz / 60Hz = 1.67 x 108Hz The frequency of the radio waves is more than 100,000,000x faster than the AC electrical current.

State the hybridization of the central atom, the molecular shape, and the bond angles for each of the following molecules or ions. Use < or > for bond angles where appropriate. CH3F, ClF2 -, BrF5

CH3F - sp3 Tetrahedral 109.5 degrees, ClF2 - sp3d2 Linear 180 degrees, BrF5 - sp3d2 Square pyramidal <90 degrees

For which of the following reactions does ∆H°rxn represent a heat of formation? C(s) + O2(g) → CO2(g)

CO2(g) + C(s) → 2CO(g) CO2(g) + H2(g) → H2O(g) + CO(g) 2 H2(g) + C(s) → CH4(g) 2 N2(g) + 3 O2(g) → 2 NO2(g) + 2 NO(g) N2(g) + O2(g) → 2 NO(g) 2 NO2(g) → N2O4(g) C(s) + O2(g) → CO2(g) and 2 H2(g) + C(s) → CH4(g)

CO32- Trigonal planar, non-polar, 120 degrees, XeF4 Square planar, non-polar, 90 degrees, PF4+ Tetrahedral, non-polar, 109.5 degrees, SbCl5 Trigonal bipyramidal, nonpolar, 90 degrees and 120 degrees

Chemical equation for when calcium and water react to form a calcium hydroxide (solution) and hydrogen gas

Ca(s) + 2H2O(l) -> Ca(OH)2(aq) + H2(g)

CaCO3 is the main component of seashells. Write the balanced equation for the standard enthalpy of formation for CaCO3(s) and calculate the standard enthalpy of formation using the following information: CaCO3(s) → CaO(s) + CO2(g)∆Hº = 178.1 kJ ∆H°f CaO = -635.5 kJ ∆ H°f H2O= -393.5 kJ

Ca+C+1.5O2 -> CaCO3 ∆Hrxn = [∆H fCao + ∆Hf CO2] - ∆Hf CaCO3 178.1kJ = [(-635.5kJ) + (-393.5kJ)] - ∆Hf CaCO3 ∆Hf CaCO3 = -1207 kJ/mol

Arrange the following atoms and ions in order from smallest to largest radius. K+, Ca2+, S2- , Cl-, Ar

Ca2+, K+, Ar, Cl-, S2-

The material often used to make artificial bones is the same material that gives natural bones their strength. Its common name is hydroxyapatite, and its formula is Ca5(PO4)3OH. Propose a systematic name for this compound. What is the mass percentage of calcium in it? When treated with hydrogen fluoride, hydroxyapatite becomes fluorapatite [Ca5(PO4)3F], an even stronger substance. Does the percent mass of Ca increase or decrease as a result of this substitution?

Calcium triphosphate monohydroxide actual name - Hydroxylapatite (5x40.1) / (5x40.1 + 284.91 + 15.999 + 1.008) = 39.9% Ca The percent mass of Ca decreases.

Describe the strengths & limitations of Valence Bond Theory with regards to calculating bond energies, calculating bond order, understanding magnetic properties, predicting molecular geometry.

Calculating bond energies - It does not. calculating bond order - It does (gives good approximation). understanding magnetic properties - It does not. predicting molecular geometry - It gives hybridized orbitals (VSEPR) which indicates molecular geometry.

The height of liquid inside a very skinny straw is higher than the level of your drink in the cup in which it is sitting. Why? If the same skinny straw was placed in a dish of mercury (don't drink!) the height of mercury in the straw would be lower than the level of mercury. Why?

Capillary action allows for hydrogen bonding to cause the liquid to appear as though it is "climbing up the sides of the straw." If it is water, it has adhesion, because the molecules are polar and more attracted to the sides of the straw. Mercury has a dominant cohesiveness. It is not attracted to the sides of the straw, because it is more attracted to itself.

The enthalpy of combustion for graphite is -393.5 kJ/mol and the enthalpy of combustion for diamond is -395.4 kJ/mol. Use this information and Hess's law to calculate the ∆Hrxn for converting diamond into graphite. Is this process endo- or exo-thermic?

Cd+O2 -> CO2 - ∆Hrxn = ∆Hcomb = -395.4 kJ/mol CO2-> O2+ Cg - ∆Hrxn = 393.5 kJ/mol Cd -> Cg - ∆Hrxn = -1.9 kJ/mol - Exothermic

Describe two ways to increase the internal energy of a gas sample.

Changing the heat or the work can both alter the internal energy because the change in energy is heat plus work.

Is this a chemical or physical change: Fish in the fridge smelling more 'fishy' with time?

Chemical - The bacteria on the fish is causing it to break down and decompose into something else.

Is this a chemical or physical change: A spot on your car where the paint was scratched starting to look brown/red?

Chemical. The actual reaction that is occurring is the formation of rust. This is a metal oxide (Fe2O3) which is forming where the metal used to be positioned.

Is this a chemical or physical change: Muffins baking in your oven?

Chemical. The ingredients within the batter (eggs, baking soda, etc.) are coming together and interacting to form a new substance

Define chemistry in 1 sentence.

Chemistry is the study of matter including its composition, structure, properties, and the various changes it undergoes along with the energy involved in the changes.

Arrange the following atoms and ions in order from smallest to largest radius. Cl, Cl-, Cs, Cs+

Cl, Cl-, Cs+, Cs

Based on their positions in the periodic table, predict which atom of the following pairs have the most negative electron affinity: (Cl, Ar) (K, Co) (S, Ge) (Sn, Te)

Cl, Co, S, Te

ClF2 - Linear non-polar 180 degrees, CH3F Tetrahedral polar 109.5 degrees, BrF5 Square pyramidal polar < 90degrees, SF2 Bent polar <109.5 degrees

Chlorite, ClO2-, is used as a bleaching agent. Perchlorate (ClO4-) interferes with the uptake of iodine into the thyroid gland and so is used to treat hyperthyroidism (overactive thyroid). Draw the Lewis structures of chlorite and perchlorate, including all resonance structures in which formal charges are closest to zero. What shape is each of the ions? Suggest a hybridization of the central chlorine atom in each ion that accounts for its shape.

ClO2- Bent ClO4- Tetrahedral Both are sp3.

State the hybridization of the central atom, the molecular shape, and the bond angles for each of the following molecules or ions. Use < or > for bond angles where appropriate. ClO3 -, BrF3, CO3 2-

ClO3 - - sp3 Trigonal Pyramidal <109.5 degrees, BrF3 - sp3d T-shaped <90 degrees, CO3 2- - sp2 Trigonal Planar 120 degrees

How many valence electrons are in cobalt? What ion(s) is cobalt most likely to form?

Co [Ar]4s23d7 This has nine valent electrons.Co2+ or Co4+

Which elements below form monatomic ions with a charge of 2-?

Column 16

Using MO theory, explain the difference between a conducting metal, a semiconductor, and an insulator. Drawing MO diagrams may help.

Conducting metals - Their valence and conduction bands overlap, allowing electrons to move between them easily. Semiconductors - Their valence and conduction bands have a small gap, causing it to be more difficult for electrons to move between them. Insulators - Their valence and conduction bands have a big gap in between, preventing electrons to move between them easily.

What is the difference between a constitutional isomer and a stereoisomer?

Constitutional isomers: Molecules which have the same formula but are structured/connected in different ways. Stereoisomers: Molecules which have the same molecular formula and atomic arrangement but different spatial arrangements.

Define Covalent bonds:

Covalent bonds are when the outer shell valence electrons are shared between two atoms.

CuO is a pigment in ceramics & is involved in the process of making rayon. Write the balanced equation for the standard enthalpy of formation for CuO(s) and calculate the standard enthalpy of formation using the following information: CuO(s) + H2(g) → Cu(s) + H2O(l) ∆Hº = -129.7 kJ ∆H°f H2O = -285.8 kJ/mol

Cu+ .5O2 -> CuO ∆Hrxn = [∆H fCu + ∆Hf H2O] - [∆Hf CuO + ∆HfH2] -129.7kJ = [0+(-285.8kJ)] - [∆HfCuO + O] ∆HfCuO = -156.1 kJ

Chemical equation for when copper(II) sulfide and silver nitrate are mixed to produce solid silver sulfide and a solution of copper(II) nitrate

CuS(aq) + 2AgNO3(aq) -> Ag2S(s) + Cu(NO3)2 (aq)

The compound geraniol is on the U.S. Food and Drug Administration's GRAS (Generally Recognized as Safe) list and can be used in foods and personal care products. By itself, geraniol has a roselike odor, but it is frequently blended with other scents to produce the fruity fragrances of some personal care products. Complete combustion of 175 mg of geraniol produces 499 mg CO2 and 184 mg H2O. What is the empirical formula of geraniol?

CxHyOz + O2 -> CO2 + H2O (.499g CO2 x 1 mol CO2 x 1 molC x 12gC) / (44gCO2 x 1mol CO2 x 1 molC) = 0.136g C / 12.011= 0.01132molC/ 0.00115 = 9.84~10 (.184g H2O x 1 mol H2O x 2 molH x 1gH) / (18g H2O x 1mol H2O x 1 molH) = 0.0206g H /1.0079= 0.0204molH/ 0.00115 = 17.74~18 0.175 - .136 - .0204 = 0.0184g O /15.999= 0.00115molO/0.00115 = 1~1 Empirical Formula: C10H18O

Birds and sailplanes take advantage of thermals (rising columns of warm air) to gain altitude with less effort than usual. Why does warm air rise?

D= PM/RT When the denominator increases as a result of the increased temperature, the density of the air will decrease and allow it to rise above cooler temperatures.

The price of gold in May was $1,228.40 per ounce (1 ounce = 28.35 g). The density of gold is 19.3 g/cm3 . Suppose a certain gold wedding ring displaced 0.55 mL of liquid when dropped in a glass of sparkling cider. How much did this wedding ring cost (assuming you paid the market price of gold).

D=m/v -- (19.3g/mL) = (m/.55mL) -- M=10.6g -- 10.6g x (1oz./28.35g) x ($1228.40/1oz.) = $460

Predict whether the entropy of the system increases or decreases in the following reaction: 2SO2(g) + O2(g) → 2SO3(g)

Decreases

Predict whether the entropy of the system increases or decreases in the following reaction: 4Fe(s) + 3O2(g) → 2Fe2O3(s)

Decreases

Predict whether the entropy of the system increases or decreases in the following reaction: CaO(s) + CO2(g) → CaCO3(s)

Decreases

Predict whether the entropy of the system increases or decreases in the following reaction: HCl(g) + NH3(g) → NH4Cl(s)

Decreases

When dentists take X-rays, the patient is given a protective shield from excess radiation. How much more energy is there per photon from a dental X-ray (λ = 71.2 pm) than from UV radiation (λ = 250 nm)?

Dental X-ray: (6.626 x 10-34J-s) (2.998 x 108m/s) = 1.99x10-25 / (7.12x10-11m) = 2.79 x 10-15J UV Radiation: (6.626 x 10-34J-s) (2.998 x 108m/s) = 1.99x10-25 / (2.5x10-7m) = 7.95x 10-19J (2.79 x 10-15J) / (7.95x 10-19J) = 3510 The Dental x-ray has 3510x more energy than the UV radiation.

Paramagnetic or diamagnetic: Mg2+

Diamagnetic

What is the difference between diastereomers and enantiomers (types of stereoisomers)?

Diastereomers deal with double bonds (cis and trans) which are stuck in place and cannot spin (not mirror image). Enantiomers requires a chiral carbon (attached to four different things). It is when it when the two arrangement of atoms are the mirror image of each other.

Petroleum (crude oil) is a complex mixture of mostly hydrocarbons that can be separated into useful fuels by distillation. In order of increasing boiling point, gasoline, jet fuel, kerosene, fuel oil, and diesel oil are all petroleum-based fuels. Based on that information, which fuel contains hydrocarbons with the highest average molar mass? Which would you predict to be most viscous at 20°C?

Diesel oil. At 20 degrees, Diesel oil would also have the highest viscosity.

For the following pairs of compounds, determine which compound will have the highest value for (a) boiling point, (b) surface tension, (c) viscosity, and (d) volatility. Briefly state why. Diethyl ether and 1-butanol, structural isomers with the chemical formula (C4H10O):

Diethyl ether - Dipole - Dipole. It has the lower intermolecular force, so it will only be higher in volatility. 1- butanol - Hydrogen Bonding. It has the stronger intermolecular force. It will be stronger in boiling point, surface tension, and viscosity.

dominant intermolecular forces for BrF3

Dipole - Dipole

dominant intermolecular forces for PF5

Dipole - Dipole

dominant intermolecular forces for PH3

Dipole - Dipole

dominant intermolecular forces for Pure phosphorous trichloride

Dipole - Dipole

dominant intermolecular forces for SF2

Dipole - Dipole

dominant intermolecular forces for SF4

Dipole - Dipole

The work function of a material is the minimum energy required to emit an electron from the material. The work function of Ag is 7.59 x 10-19 J. If I'm in Australia (where a lot more UV light makes it through the depleted ozone layer...) and I'm wearing silver earrings when the sun comes out irradiating me with light that has a wavelength of 185 nm, will electrons be emitted from my earrings? If radiation hits me that has more energy than required to emit an electron from my silver earrings, what happens to the additional energy?

E = (hc/λ) = (6.626 x 10-34J-s) (2.998 x 108m/s) = 1.99x10-25/ (1.85x10-7m) = 1.07 x 10-18J Yes, because there is more energy than the work function. The additional energy will become kinetic energy (which can be measured).

How much energy would it take to remove an electron in an H atom if it was in the n=2 level?

E = -hcRH(1/h2 ) = 5.45 x 10^-19 J

Calculate the wavelength and frequency of a photon emitted when an electron jumps down from n = 5 to n = 1 in a H atom.

E = -hcRH(1/h2 - 1/h2) = -2.09 x 10^-18 J V = 3.16 x 10^15Hz wavelength = 9.5 x 10^-1m

A photon of what frequency and energy would be required to excite an H atom's lone electron from n = 2 to n = 4?

E = -hcRH(1/h2 - 1/h2)= 4.086x10^-19j / 6.26 x 10^-34 Js = 6.17 x 10^14

Our understanding of the H atom will help us learn about atoms with more electrons. The n =1 electron energy level of a H atom has an energy of -2.18 x10-18 J. What is the energy of the n = 5 level?

E = -hcRH(1/h2) = -(6.626x10-34) x (2.998x108) x (1.0973731568508x107) x (1/52) = -8.72x10-20 J

The rod cells in the eyes absorb 498 nm light. What is the energy difference (in Joules) between the HOMO and LUMO of the retinal that absorbs this light?

E= (hc)/498x10-9 = 3.99 x 10-19 J

For the n=3 shell, how many total nodes will each orbital have? How many nodes are radial and how many are planar?

Each orbital will have 2 total notes (3-1). With n=3, there are three subshells (l= 0, 1, 2). l=0 will have 0 angular nodes (3s will have 2 radial nodes), l=1 will have 1 radial node and 1 angular, and l=2 will have 2 angular nodes and no radial nodes.

It's harder to drink eggnog (non-alcoholic, of course) through a straw than water. Why?

Eggnog has a higher viscosity and water is less viscous than eggnog.

Define electronegativity in your own words.

Electronegativity is an atom's ability or tendency to attract electrons to itself during chemical bonding.

How can an electron get from one lobe of a p orbital to the other without going through the point of zero electron density between them?

Electrons can move as particles and waves. In this instance, it would be best to view them as waves. A node is simply when the amplitude is zero. Waves can pass through nodes having amplitude on either side and having zero amplitude at the point of the node.

Exothermic or endothermic? Ice cubes in a frost-free freezer slowly lose mass

Endothermic

Exothermic or endothermic? Rubbing alcohol evaporates from the skin

Endothermic

First Law of Thermodynamics in 1 sentence using your own words. Use any appropriate equations.

Energy is conserved (the change of energy of the universe is zero). In other words, energy will cannot be created nor destroyed.

How are energy and work related?

Energy is transferred from and through different objects as work or thermal energy.

Define enthalpy.

Enthalpy is the total energy of a system.

Define entropy, using any appropriate equations.

Entropy is a measure of the unusable energy/disorder in closed thermodynamic systems. ∆S = qrev,iso /T

Ethane - London Dispersion. It will have stronger volatility. Ethanol - Hydrogen Bonding. It has intermolecular forces, so it will have a higher boiling point, surface tension, and viscosity.

Ethanol - Hydrogen Bonding. It has the stronger intermolecular force. It will be stronger in boiling point, surface tension, and viscosity. Ethanethiol - Dipole - Dipole. It has the lower intermolecular force, so it will only be higher in volatility.

Exothermic or endothermic? Dew forms on a lawn overnight

Exothermic

Exothermic or endothermic? Fog forms over San Francisco Bay

Exothermic

Exothermic or endothermic? Ice cubes solidify in the freezer

Exothermic

Exothermic or endothermic? Molten aluminum solidifies

Exothermic

Gases A and B have molecular weights of 65.2 g/mol and 101.2 g/mol, respectively. What is the rms velocity of these molecules at 23 ºC? (just for fun, you can convert their speeds to mph to see if these molecules would get a ticket on the freeway)

Gas A: 337 m/s ~754 mph Gas B: 270 m/s ~604 mph

Why does a hot needle sinks when placed on the surface of cold water, but a cold needle floats.

Hot needles have the energy to break the hydrogen bonds and the surface tension breaks.

What is the difference between a group and period in the Periodic Table?

Groups are Columns Periods are rows

An industrial process for producing hydrogen gas is based on the reaction between steam and carbon heated to incandescence, producing a mixture of CO and H2 called synthesis gas, or syngas. Write a balanced chemical equation describing the production of syngas. If a reaction vessel that initially contains 66 kilograms of incandescent carbon and excess steam produces 6.8 kg H2, what is the percent yield?

H2O (g) + C(s) -> CO(g) + H2(g) (66kgC x 1000gC x 2gH2 x 2gH2) / (12gC x 1000gH2) = 11kg H2 6.8/11 = 61.8% yield

Chemical equation for when 7.21b a mixture of nitric acid and nitrous acid is formed when water reacts with dinitrogen tetroxide

H2O(l) + N2O4(aq)-> HNO3(aq) + HNO2(aq)

What is the difference between the hybrid orbitals discussed in Valence Bond Theory and the molecular orbitals of MO Theory?

Hybrid orbitals are formed by the interactions of atomic orbitals in the same atom (VB), while the molecular orbitals are created from multiple atomic orbitals combining.

dominant intermolecular forces for H2O

Hydrogen Bond

What is the difference between heat capacity, molar heat capacity, and specific heat capacity?

Heat capacity is in J/°C and is for an object, Molar heat is J/mol°C, and specific heat capacity is in J/g°C and both molar and specific are for pure substances.

Rank the gases NO, NO2, N2O4, and N2O5 in order of increasing root-mean-square speed at 0°C.

Heaviest to the lightest -> N2O5, N2O4, NO2, NO

You're at the beach on a warm summer day. Your toes felt nice and cool swimming in the ocean. Then, you walked barefoot to the ice cream stand and noticed that the wet sand was much warmer than the ocean. Walking across the paved parking lot to your car, the black asphalt was even hotter (almost as hot as the dry sand!) and you vowed to never forget your flip flops again. Resting one hand on your car for balance while you tried to wipe the dirt & sand from your feet was a big mistake - the metal was too hot to touch! Rank the four materials (water, wet sand, asphalt, & metal) in order of lowest to highest heat capacity and explain your reasoning.

Highest temperature means the lowest heat capacity. Metal - > Asphalt -> Sand -> Water. Water would have the lowest temperature and the highest heat capacity, because it absorbs the same amount of energy while changing the smallest amount regarding temperature. Metal, on the other hand, absorbs the same amount of energy while changing the largest amount regarding temperature, meaning that it has the smallest heat capacity.

The compound COCl2 has been used as a chemical warfare agent (phosgene). It and two similar compounds, COBr2 and COI2, are all eye irritants and cause skin to blister. The severity of the skin reactions is influenced by the polarity of the compounds. Rank the compounds in order of increasing polarity of their carbon-halogen bonds.

Highest: COCl2, Middle: COBr2, Last: COI2

How many valence electrons are in iodine? What ion is iodine likely to form?

I [Kr]5s24d104p7 This has nine valence electrons. I-

What does the sign of ∆G tell you about the spontaneity of a process?

If it is less than zero, than it is spontaneous. If it is less than zero, than depending on the signs of deltaH and deltaS, it is either spontaneous at high temperatures (+, +) or spontaneous at low temperatures (-, -). If it is greater than zero, than it is never spontaneous.

Can the results of a combustion analysis ever give the true molecular formula of a compound?

If the empirical formula and the molecular formula are the same then yes.

When does ∆H equal q?

If there is constant pressure, ∆P is 0 so the change in energy will equal ∆H which will lead to q equaling ∆H.

Why do we spin food in microwaves?

If we spin food, there is a slimmer change of sections of the food not cookin'

What is the Pauli Exclusion Principle?

No 2 electrons will have the same set of quantum numbers

What orbitals are degenerate in all other atoms? Why is there a difference?

In atoms other than hydrogen atoms, the repulsion between electrons occurs when 1+ electrons are present in an atom causes orbitals with the same "n" and the same number "l" to be degenerate.

How can we use electronegativity to predict whether a bond between two atoms is likely to be covalent or ionic?

In general, large differences in electronegativity create ionic bonds (if the change is greater than 2). If the difference in electronegativity is smaller, however the bond should be covalent (smaller than 2).

Why do real gases behave nonideally at very low temperatures and very high pressures?

In ideal gases, there are no intermolecular forces. However, at high pressures, they are squished together and there is an increase in intermolecular forces felt in the gases. At low temperatures, it also breaks down, because the molecules slow down and are more likely to recognize each other as they pass one another.

How does the concept of an orbit in the Bohr model of the hydrogen atom differ from the concept of an orbital in quantum theory?

In the Bohr model, the electrons are treated as particles, fitting in 2D quantized, specific rings (defines where they are). An orbital in quantum theory, it is 3D, electrons are treated as waves a general location where electrons could be.

Predict whether the entropy of the system increases or decreases in the following reaction: AgCl(s) → Ag+ (aq) + Cl- (aq)

Increases

Predict whether the entropy of the system increases or decreases in the following reaction: CO2(s) → CO2(g)

Increases

Predict whether the entropy of the system increases or decreases in the following reaction: H2O(l) → H2O(g)

Increases

What are intensive physical properties?

Independent of quantity (innate) - color, smell, density, conductivity, solubility

What is the difference between internal energy and enthalpy?

Internal energy includes both kinetic energy and potential energy. Enthalpy, on the other hand, is the energy needed to displace the surrounding environment.

Which elements below form monatomic ions with a charge of 1-?

Iodine (Column 17)

Which of the following will exhibit the strongest London Dispersion forces? Explain your reasoning. Helium (He) Nitrogen (N2)Oxygen (O2) Iodine (I2)Fluorine (F2)

Iodine - Its radius is the largest of the elements (biggest with the most electrons)

dominant intermolecular forces for CrCl3

Ion - Ion

dominant intermolecular forces for MgF2

Ionic

What type of bonds are expected in NaCl

Ionic bond

Define Ionic bonds:

Ionic bonds are when an atom transfers/gives up 1 or more electrons to another.

Define isomer.

Isomers have the same chemical formula, but it have different arrangements of atoms.

The melting point of solid hydrogen is 15.0 K at 1.00 atm. The temperature of its triple point is 13.8 K at 0.0695 atm. Does liquid H2 expand or contract when it freezes?

It contracts when it freezes.

What happens to food in microwaves at the nodes?

It doesn't cook

When an atom forms an anion, its radius increases. When an atom forms a cation, its radius decreases. Explain why this is so.

It gains an electron if it is an anion. This means that electrons are repelling against each other and expanding the radius. It loses an electron to be a cation. This means that electrons are moving a bit closer together (decreases radius).

How does the RMS speed of a N2 molecule in a gas sample change under the following conditions (assuming the gas behaves ideally)? Increasing the temperature, increasing volume, adding AR gas and maintaining the same T

It increases, it does nothing, it does nothing.

Explain what is meant by a state function.

It is a property or element which is separate from the changing element. It is constant and path independent (like volume)

What is meant by the root-mean-square (RMS) speed of gas particles?

It is the velocity of the gas particles with relation to the average KE of the gas. You are taking the square root of the average.

"Photo-gray" lenses for eyeglasses darken in bright sunshine because the lenses contain tiny, transparent AgCl crystals. Exposure to light removes electrons from Cl- ions, forming a chlorine atom in an excited state (indicated below by the asterisk): Cl- →hn Cl* + e- The electrons are transferred to Ag+ ions, forming silver metal: Ag+ + e- → Ag Silver metal is reflective, producing the photo-gray color. How might substitution of AgBr for AgCl affect the light sensitivity of photo-gray lenses? In answering this question, consider whether more or less energy is needed to remove an electron from a Br- ion than from a Cl- ion.

It will be easier to remove an electron from Br-. The glasses may appear to be shaded too easily.

If you had equal masses of the substances in the following pairs of compounds, which of the two would contain the greater number of ions? NaBr or KCl, NaCl or MgCl2, CrCl3 or Na2S

KCl, NaCl, Na2S

Lead metal (11.3 x 109 ng/ml), tungsten (0.019 kg/ml), and liquid mercury (13.5 g/cm3 ) are all very dense. If chunks of lead and tungsten are placed in liquid mercury, will they sink or float? Does it matter what size the chunks are? Why or why not?

Lead 11.3x10^9ng x (1x10^-9/1ng) = 11.3g/mL Tungsten 0.019kg x (1000g/1kg) = 19g/mL Lead is less dense than mercury so it will float, while tungsten is denser than mercury, so it will sink. It does not matter what size the chunks are, because the quality of sinking and floating is determined solely by the density of the substance.

John Dalton and the atom

Like billiard balls with hooks that randomly moved and smashed into one another

dominant intermolecular forces for BeH2

London Dispersion

dominant intermolecular forces for CH4

London Dispersion

dominant intermolecular forces for CS2

London Dispersion

dominant intermolecular forces for Crayon (colored wax, or paraffin, which is a mixture of hydrocarbons with 20-40 carbons)

London Dispersion

dominant intermolecular forces for Gasoline (a mixture of hydrocarbons with 4-12 carbons)

London Dispersion

dominant intermolecular forces for Pure boron trichloride

London Dispersion

dominant intermolecular forces for SF6

London Dispersion

dominant intermolecular forces for XeF2

London Dispersion

dominant intermolecular forces for XeF4

London Dispersion

Steel and iron are often 'galvanized' or coated with a thin layer of zinc metal to prevent corrosion (iron rusts but zinc does not). (a) What is the longest wavelength of light (in nm) that can eject electrons from zinc metal? (i.e. assume the electron's kinetic energy is very close to zero.) The work function of zinc = 4.3 eV and 1 electron-volt (eV) = 1.602x10-19 J.

Longest wavelength of light means that it will have equal energy to the work function Φ = 4.3 eV x (1.602x10-19 J) = 6.9 x 10-19 Φ = E = (hc/wavelength) Wavelength = (hc/ Φ) = (6.626 x10-34J-s)(2.998 x 108m/s) = 1.99x10-25 / (6.9x10-19) = 290 nm

Rank the compounds in each set-in order of increasing boiling point. I2, ICl, Br2

Lowest Br2, ICl, I2 Highest

Rank the compounds in each set-in order of increasing boiling point.CCl4, CF4, CH4

Lowest CH4, CF4, CCl4 Highest

Rank the compounds in each set-in order of increasing boiling point. NH3, CH4, and SiH4

Lowest CH4, SiH4, NH3 Highest

Among the diatomic molecules detected in interstellar space are CO, CS, SiO, SO, and NO. Arrange the molecules in order of increasing polarity.

Lowest: CS, NO, CO = SO, Highest: SiO

Medical X-rays are often produced by slamming fast-moving electrons into a piece of tungsten metal and can have a wavelength as small as (λ = 20.9 pm). How much energy is in one of these X-ray photons?

Medical X-ray: (6.626 x 10-34J-s) (2.998 x 108m/s) = 1.99x10-25 / (2.09x10-11m) = 9.50 x 10-15J

The meniscus of the mercury in a mercury thermometer is convex whereas the meniscus of the alcohol in an alcohol thermometer is concave. Why?

Mercury is nonpolar and will enjoy itself while alcohol is hydrogen bonding so it will be attracted to the sides of the thermometer.

What type of bonds are expected in Mercury

Metallic bond

What type of bonds are expected in Tin

Metallic bond

Define Metallic bonds:

Metallic bonds are a unique bond which holds metals together in a metal crystal structure. It is neither covalent nor ionic and is marked by the fact that it contains delocalized electrons which move freely around the positively charged protons.

An unknown organic compound has the simplest formula CH2. If its molecular weight is 28 g/mol, what is the molecular formula?

Mf: C2H4

In an aqueous solution containing Na+, Mg2+, K+, and Ca2+ salts, which do you expect to experience the strongest ion-dipole interactions? Why?

Mg2+, because it has a charge of 2+ and is smaller than Ca2+so it can get closer to the water molecules.

Inhalation of asbestos fibers may lead to a lung disease known as asbestosis and to a form of lung cancer called mesothelioma. One form of asbestos, chrysotile, is 26.31% magnesium, 20.27% silicon, and 1.45% hydrogen by mass, with the remainder of the mass as oxygen. What is the empirical formula of chrysotile?

Mg26.31/24.305 g(per mole) = 1.083/.7217 = 1.502 ~1.5, Si 20.27/28.085 g(per mole) = 0.7217/.7217 = 1 ~ 1, H 1.45/1.0079 g(per mole) = 1.439/.7217 = 1.994 ~ 2, O 52.97/15.999 g(per mole) = 3.248/.7217 = 4.500 ~ 4.5 Empirical Formula: Mg3Si2H4O9

Which are the possible values of ml when l = 2?

Ml = −2, −1, 0, 1, 2

What is a mixture?

More than one element in the frame, but they aren't compounding.

What is a standing wave?

Standing wave, or stationary wave, is a combination of two waves moving in opposite directions, each having the same amplitude and frequency.

Safety airbags in automobiles inflate when a sudden jolt causes a spark to hit a pocket of white sodium azide (NaN3) powder, which rapidly decomposes to elemental sodium and nitrogen gas (which inflates the airbag): __2_NaN3 (s) → __2__Na(s) + __3__N2(g) How many grams of NaN3 are needed to inflate an air bag to 36 L with a pressure of 1.15 atm at a temperature of 26.0 ºC?

N = PV/RT = 1.69 mol N2 (1.69 mol N2 x 2 molNaN3 x 65.01g NaN3) / (3 mol N2) = 73.24g NaN3

The compound, NaCl, consists of sodium cations and chlorine anions. The sodium and chlorine ions are not the same size as they are in the elemental state. Explain how their relative sizes change (larger or smaller) in relationship to their size in the elemental state.

Na - Na+ Smaller Cl - Cl- Larger Relative size of Na shrinks, while the relative size of Cl grows larger.

Chemical equation for when sodium phosphide reacts with water to produce phosphine (PH3) gas and a solution of sodium hydroxide

Na3P(s) + H2O (l) -> PH (g) + 3NaOH(aq)

Arrange the following atoms and ions in order from smallest to largest radius. Ne, Ne+, Ne-

Ne+, Ne, Ne-

Arrange the following atoms and ions in order from smallest to largest radius. Al, Cs, Ne, Rb, S

Ne, S, Al, Rb, Cs

Does pressure affect the root-mean-square speed of the particles in a gas? Why or why not?

No, because it is not in the equation of UMS speed. It would just change the pace at which the particles ran into the walls of the container or other particles.

Can the quantity of CO2 obtained in a combustion analysis be a direct measure of the oxygen content of the starting material? Why or why not?

No, because there is oxygen in H2O and we are also adding oxygen, so the numbers are skewed.

What type of bonds are expected in Diamond (pure carbon)

Non-polar covalent bond

What type of bonds are expected in Iodine (I2)

Non-polar covalent bond

What type of bonds are expected in Methane (CH4)

Non-polar covalent bond

What type of bonds are expected in Oxygen (O2)

Non-polar covalent bond

Define non-polar covalent bonds:

Non-polar covalent bonds result from an even charge distribution between the two atoms, where power and electrons are shared equally.

A sample of O2 gas is compressed by transferring it to a smaller container while keeping the T constant. What change do you expect in: the average kinetic energy of the molecules, the average speed of the molecules, the number of collisions that the molecules make with the container walls per unit time, the pressure of the container increases

Nothing happens, nothing happens, the number of collisions will increase, the pressure will also increase

The boiling point of O2 is -183°C (90 K) and the boiling point of N2 is -195°C (77 K). Briefly explain why the boiling point of oxygen is higher than that of nitrogen. Describe how O2 and N2 could be separated on the basis of their boiling points (allowing us to have pure O2 to make solid O2 rocket fuel and pure N2 to make liquid nitrogen ice cream).

O2 has higher intermolecular forces than N2, because both are nonpolar (London Dispersion) and O2 has more electrons. N2 has a lower boiling point, meaning that at -195°C, N2 will have reached a gaseous state, while O2 remains a liquid.

What is the scientific method?

Observation, hypothesis, experiment, theory

Until the 1960's, all of the Noble Gasses were thought to be totally unreactive. This changed when XeF4 was made. Draw the Lewis structure of XeF4. What is the electron geometry of Xe? Molecular shape? Orbital hybridization of the Xe?

Octahedral, Square Planar, sp3d2

Predict which liquids in the following sets have the greatest surface tension: hexane (C6H14) or octane (C8H18)? Ethanol, CH3CH2OH, or acetic acid, CH3COOH?

Octane and acetic acid

What is a Pure element?

One type of atom in the frame.

Chemical equation for when 7.22c Phosphorus (P4) burns in air to give diphosphorus pentoxide

P4(g) + 5O2(g) -> 2P2O5(g)

Calculate the pressure of the gas mixture and the partial pressure of each constituent gas if the mixture is in a 5.0 L vessel at 20°C.

PV = nRT 10.8 atm PH2 = 4.8 atm PN2 = 1.7 atm PCH4 = 4.3

What is the volume of 1 mole of an ideal gas at STP? Does it matter what gas?

PV = nRT V = nRT/P = (0.08206)(273) = 22.4L

What is meant by the partial pressure of a gas?

Partial pressure is the pressure exerted by one individual gas.

Hess's law can be used to find standard enthalpies of formation. PbO is the key component of automotive lead-acid batteries and is also used extensively in making lead glass (or SiO2 doped with PbO, which enables the glass to block X-rays). Write a balanced equation for the standard enthalpy of formation for PbO(s) and calculate the standard enthalpy of formation using the following information. PbO(s) + C(graphite) -> Pb(s) + CO(g) ∆H° = 107 kJ. 2C(graphite) + O2(g) -> 2 CO(g) ∆H ° = -222 kJ

Pb + CO -> PbO + C - ∆H = -107kJ C+ .5O2 -> CO - ∆H = -111kJ Pb+ .5O2 -> PbO - ∆HfPbO = -218kJ/molPbO

Ancient Egyptians used lead compounds including PbS, PbCO3, and Pb2Cl2CO3 as pigments in cosmetics, and many people suffered from chronic lead poisoning as a result. Calculate the percentage of lead in each of the compounds.

PbS (207.2/ 207.2+32) = 86.6 %Pb, PbCO3 (207.2/ 207.2 +12+3x16) = 77.5% Pb, Pb2Cl2CO3 (2x207.2 / (2x207.2 + 2x35.5 + 12 + 3x16)) = 76.0% Pb

Explain the difference between potential and kinetic energy?

Potential energy is energy which is stored in objects due to its makeup or position. Kinetic energy, on the other hand, is the energy of motion.

Is this a chemical or physical change: Salt crystals forming on a hot day by the Great Salt Lake?

Physical. Before you have NaC1 in the water, and after they are out of the water. There is no change in chemical identity.

Is this a chemical or physical change: Soda going 'flat' as dissolved CO2 comes out of solution?

Physical. Before, CO2 was inside the soda. After, it is simply out of the soda and there is no change to the actual molecular identity of the substance.

Is this a chemical or physical change: Soldering a pipe in your house?

Physical. When you solder a pipe, you are melting and then allowing the binding metal to solidify and bring the two sides together. There is no change to chemical identity.

What type of bonds are expected in NO2

Polar Covalent bond

Explain the difference between a polar bond and a polar molecule.

Polar bonds occur when there is a difference in electronegativity between atoms in the bond (<0.4) Polar molecules occur when there is an asymmetrical distribution of electron charge.

What type of bonds are expected in Carbon monoxide

Polar covalent bond

Define polar covalent bonds:

Polar covalent bonds results from an uneven charge distribution or when one atom is pulling harder (more attraction) on the electrons so there is a lack of power balance (biggest charge in EN is the most polar)

What type of bonds are expected in H2O

Polar-Covalent bond

What is precision?

Precision: How repeatable/reproducible a measurement/value and is expressed as a ± range.

What are extensive physical properties?

Properties that are dependent on quantity - length, width, mass, volume

Refrigerators and freezers remove heat from food by evaporating volatile liquids such as CF4 and then re-compressing the vapor back into a liquid. Calculate what mass of water at 0.0 ºC can be converted into ice at 0.0 ºC when 100. g of CF4 evaporates? (∆Hvap = 136 kJ/kg for CF4)

QCF4 + qwater = 0, NCF4∆HvapCF4 = -nwater∆Hfreezewater = (.1kg)(136 kJ/kg) = -n(-6.01 kJ/mol) nwater = 2.26 mol x 18 = 40.7g H2O

A 40.0g piece of gold at 76.2 ºC is dropped into 10.0g of water at 20.0 ºC. After a short time, both the gold and the water reach a stable temperature of 26.2 ºC. Use this information to calculate the specific heat of gold.

Qgold=-qwater, mgCg ΔTg= - mwCw ΔTw, (40)Cg(26.2-76.2) = -(10)(4.18)(26.2-20), (-2000g°C) Cg = -259.16J, Cg = 0.130J/g°C

In an experiment, you scoop up a handful of sand (SiO2) on a very hot day at the beach. The sand just happens to be 2.00 x 102 g exactly and 96.7°C (ok maybe this is Death Valley). You quickly transferred the sand to 1.25 x 102 g of water at 15.2°C. The final temperature comes to 32.5°C. What is the specific heat capacity of sand (SiO2)? [Cp(water) = 4.18 J/(g·°C)]

Qsand+qwater = 0, MsCsΔTs +mwCwΔTw = 0, (200g)(Cs)(32.5-96.7) + (125g)(4.18)(32.5-13.2) = 0, -12840Cs+9039.25J = 0, Cs = 0.704J/g°C

What is the difference between a planar and a radial node?

Radial nodes are spherical and centered around the nucleus. Planar nodes, on the other hand go through the nucleus (the lines).

Which of the following atoms has the smallest first ionization energy? Al P Sr Ga Rb

The Periodic Table can be divided into roughly 4 blocks according to the type of subshell being filled. State the subshell being filled in each of these blocks.

S D P F

State the hybridization of the central atom, the molecular shape, and the bond angles for each of the following molecules or ions. Use < or > for bond angles where appropriate. SF2, BeF2, XeF2

SF2 - sp3 Bent <109.5 degrees, BeF2 - sp Linear 180 degrees, XeF2 - sp3d Linear 180 degrees

State the type of matter for saltwater, purified sugar, high pulp orange juice, apple juice, diamond, gravel, compressed air in a scuba tank, solid butter, baking soda, pure copper plumbing pipes?

Saltwater - homo mix, purified sugar - compound, high pulp orange juice - hetero mix, apple juice - homo mix, diamond - element, gravel - hetero mix, compressed air in a scuba tank - homo mix, solid butter - homo mix, baking soda - compound, pure copper plumbing pipes - element.

An electron can be removed from Na or Rb by electromagnetic radiation (the photoelectric effect). Which element, Na or Rb, would require the shortest wavelength to remove the electron?

Shortest wavelength means highest energy. Sodium will have the higher energy, so it will have the shortest wavelength.

What are the region(s) of electron density in the sigma and pi bonds?

Sigma is between nuclei. Pi is outside of nuclei.

What are the overlapping orbitals that can produce sigma and pi bonds?

Sigma: s sp sp2 sp3 sp3d sp3d2 p, Pi: p

Which elements below form monatomic ions with a charge of 1+?

Silver and most of period 1

Size, ionization energy, and electron affinity are all properties that show definite trends across the Periodic Table. Describe the trends for each of these properties going down a group and across a period.

Size: Size increases down and to the left, Ionization Energy: It increases going up and to the right, Electron Affinity: It increases going up and to the right.

When measuring the heat of combustion of a very small amount of material, would it be better to use a calorimeter having a heat capacity that is small or large?

Small

What does it mean when ∆G = 0?

So, if the free energy is zero, then the reaction is at equilibrium, and no more work can be done.

The reactor-core cooling systems in some nuclear power plants use liquid sodium as the coolant. Sodium has a thermal conductivity of 1.42 J/(cm · s · K), which is quite high compared with that of water [6.1 ´ 10-3 J/(cm · s · K)]. The respective molar heat capacities are 28.3 J/(mol · K) and 75.3 kJ/(mol · K). What is the advantage of using liquid sodium over water in this application?

Sodium moves a lot faster than water. Heat is produced so fast that it needs to be transferred as fast as possible to get it away from the cooler. Since Sodium moves faster when it comes to thermal conductivity, it would be more successful at separating the heat from the cooling

List and briefly define (1 sentence) all possible phase changes.

Solid to liquid is described as melting. Liquid to solid is freezing. Liquid to gas is vaporation. Solid to gas is sublimation. Gas to solid is deposition. Gas to liquid is called condensation.

Blackbody radiation can also be used to study stars. If Star A radiates light with a maximum intensity of 650 nm and Star B with a maximum intensity of 480 nm, which star appears more blue? The visible range of the electromagnetic spectrum is about 400-750 nm.

Star B will appear more blue. In general, blue light radiation lies between 520nm and 420nm, meaning if the max intensity of Star B is 480nm it will be more blue which Star A will appear more orange

Coulomb's Law of Electrostatic Interaction

Strength of interaction depends on magnitude of charges and the distance between them (F=k(q1q2)/r2)

Marie Curie

Studied Uranium, parts of atoms have positive charge, described 3 types of radiation (alpha+, beta-, gamma rays)

What is scientific law?

Summary of accepted facts of nature (what is observed)

Comfortable room temperature is about 72°F. Body temperature is about 98°F. Water freezes at 32° F and boils at 212°F. The lowest temperature ever recorded at sea level (by a human) was -128.6°F at the Soviet Vostok Station in Antarctica, on July 21, 1983. Convert these temperatures to °C and K.

T(°𝐶) = (5/9) [𝑇(°F) − 32] 𝑇(°C) = −89.22 → −89.22° C + 273 = 184𝐾

Teflon is formed when C2F2 is polymerized, or in other words, when the pi bonding electrons are used to form sigma bonds between molecules, linking many C2F4 molecules together in a long chain (a polymer). What intermolecular forces do you think dominate in Teflon? Hydrophobic or hydrophilic?

Teflon is dominated by London dispersion. Hydrophobic, because water is polar but Teflon is nonpolar.

Suppose you have a container of gas with a molecular weight of 16.48 g/mol. If the RMS speed is 852.4 m/s, what is the temperature of the gas?

Temperature is 480 K.

What are the metric prefixes?

Ten Giant Monsters Killed One Million Men Near Pennsylvania Tera and pico (10^12) Giga and nano (10^9) Mega and Micro (10^6) Kilo and Milli (10^3) (hecto and centi) (10^2) (deca and deci) 10^1)

Tungsten (W) is the favored metal for lightbulb filaments, in part because of its high melting point. The enthalpy and entropy of fusion for tungsten is 35.4 kJ/mol and 9.58 J/mol·K, respectively. What is the melting point of tungsten in °C and °F?

Tfus= ∆H/∆S = (35400 J/mol)/ 9.58J/mol = 3695K = 3422 Celsius = 6191 Fahrenheit

State the 3rd law of thermodynamics in one sentence using your own words. Use any appropriate equations.

The actual entropy equals 0 in a perfect crystal at 0 Kelvin. (S=0)

Naturally occurring Mg has three stable isotopes, 24Mg, 25Mg, 26Mg. This means that there are three forms of Mg atoms, each with a unique atomic weight. This appears to be contrary to the idea that atomic weight is the defining property of an element. Explain (in 3 sentences or less) why all three of these types of atoms are indeed the same element.

The chemical behaviors of elements are not reliant on protons or neutrons, rather they are caused by the number of electrons. This means that although elements may differ slightly in atomic mass due to a change in neutrons, as long as they maintain the same number of electrons, their chemical behaviors will remain the same. An element may have up to 36 isotopes which will all differ in atomic mass, but their singular elemental identity is reliant upon their electron count not their neutrons or protons.

As one transitions between quantum levels, what pattern becomes apparent?

The closer you get to the nucleus, the larger the distances are and the greater the energy.

Explain how the electron configurations of the group 2 elements are linked to their location in the periodic table.

The columns will all end in nx2.

What is the difference between ∆H°rxn and ∆Hrxn?

The degree means that we are at STP so the temp is 25 degrees and the pressure is 1 atm.

What are chemical changes?

The diagrams are depicting the alteration of the identity to two elements at an atomic/molecular level. Mixed elements are combined to create a single, solid compound of elements (ordered array).

What are physical changes?

The diagrams are depicting the alteration of the identity to two elements at an atomic/molecular level. Mixed elements are combined to create a single, solid compound of elements (ordered array).

Is the emission associated with the n = 2 → n = 1 transition in a one-electron ion ever in the visible region? Why or why not?

The emission associated with n=2 to n=1 is one that will not ever be in the visible spectrum, because the frequency is too high (no matter the known atomic number).

Define Gibb's free energy.

The energy available to do useful work - the "free energy"

State the 2nd law of thermodynamics in one sentence using your own words. Use any appropriate equations.

The entropy of isolated systems will never decrease (any spontaneous reaction will escalate entropy levels). ΔS univ > 0

How do we know from examining the periodic table that the 4s orbital is filled before the 3d orbitals?

The forth row in the s block comes before the third row in the d block.

Which radiation has the higher frequency, (a) the red light on a bar-code reader at a grocery store or (b) the green light on the battery charger for a laptop computer?

The green light on the battery charger for a laptop computer has a higher frequency.

The temperature of a lava flow can be estimated by observing the color of the molten lava. Based on the color/temperature scale (generated for hot metal being forged) provided here, estimate the temperature of the hottest part of the lava flow in this picture.

The hottest part of the lava flow in the picture is probably around 1000-1200 °C.

Why can a carefully placed needle can float on water but sinks in methanol.

The hydrogen bonding causes strong surface tension.

What is calorimetry?

The measurement of calories or specific amounts of energy

What is mole?

The mole is a unit of measurement used in chemistry to describe amount of a substance which contains the same number of atoms/molecules/ ions/electrons/etc. as 12 grams of carbon-12. That number of particles is also known as Avogadro's Number or 6.022x1023.

What is an orbital?

The orbital is a 3D boundary or region where there is a 90% probability of finding an electron.

How can you tell how many planar and radial nodes an orbital will have?

The number of planar nodes is equivalent of the quantum number l. The rest are radial. That just means that it will be (n-1)-1 radial nodes.

State which quantum number is associated with the notions of shell, subshell, and specific orbital of an electron.

The principle number (n) is associated with the shell. The angular momentum quantum number (l) is associated with the subshell. The magnetic quantum number (ml) is associated with specific orbital.

The first ionization energies (IE) of hydrogen and helium are about 1300 kJ/mol and 2300 kJ/mol respectively. Yet, the electron removed from both of these originated in a 1s orbital. Explain in 1-3sentences the large IE difference observed between these elements.

The pull on the helium electron is almost double that of hydrogen meaning that it is a lot harder to remove the electron. This means that there is a higher ionization energy.

Breaking the small pouch of water inside a chemical cold pack containing ammonium nitrate activates the pack, which is used by sports trainers for injured athletes. What is the sign of ∆H for the process taking place in the cold pack? Does ∆H equal q in this process?

The sign is positive (+ ∆H) and yes it will.

Adding Drano to a clogged sink causes the drainpipe to get warm. What is the sign of ∆H when Drano dissolves in water?

The sign will be negative (- ∆H).

Why do Icebergs float instead of sinking.

The solid water is less dense than liquid water. Because of its unique bend shape, when it freezes it creates complex, hexagonal shapes which are less dense.

What does the square of the wave function (Ψ2) tell you?

The square of the wave function gives the probability density or orbital.

What are ∆Hvap, ∆Hfus, ∆Hrxn, and ∆Hf and how do they differ?

The subscripts relate to the topic that the heat is describing. ∆Hvap relates to the heat associated with vaporization , ∆Hfus with melting or fusing, ∆Hrxn with chemical reactions, and ∆Hf with formation.

Explain the inherent redundancy in the nuclide symbol AZX.

The symbol AZX is redundant, because the "A" represents the Atomic Number or the number of protons in that specific nuclide. The "Z" represents the mass number of the nuclide, meaning that it represents the number of protons plus the number of neutrons. This means that the number of protons is being expressed twice.

What do wave functions (Ψ) tell you?

The wave functions describes electrons at certain energy levels. Essentially, their allowed energy state.

Balmer observed a hydrogen emission line for the transition from n=6 to n=2, but not for the transition from n=7 to n=2. Why?

The wavelength released between n=7 and n=2 is beyond the scope of recognition.

For the n=5 shell, How many subshells are there? How many orbitals are in each subshell? How many total orbitals are there?

There are 5 subshells (0,1,2,3,4), l=0 has 1 orbital, l=1 has 3 orbitals, l=2 has 5 orbitals, l=3 has 7 orbitals, l=4 has 9 orbitals so there are 25 total orbitals.

The helium balloon you got on your birthday has almost entirely deflated, but there is still a very small amount of 4He inside with a total mass of 160 amu. How many protons, neutrons, and electrons are present in the balloon (assuming only 4He is there)?

There are 80 protons, 80 electrons, and 80 neutrons present in the balloon.

How many quantum numbers are needed to identify an orbital? How many are needed to uniquely identify an electron in an atom? Why is there a difference?

There are three quantum numbers needed to identify an orbital. Four are needed to identify an atom, because in the orbital there are two electrons so it specifies which orbital.

Azides such as sodium azide, NaN3, are used in automobile airbags as a source of nitrogen gas. Another compound with three nitrogen atoms bonded together is N3F. What differences are there between the arrangements of the electrons around the nitrogen atoms in the azide ion (N3- ) and in N3F? Is there a difference in the hybridization of the central nitrogen atom?

There is no difference, except on the N3F the nitrogen that is attached to the F is shares a bonded electron and has a neutral charge.

If the real weight of an object is 100 grams, state whether the following measurements are precise, accurate, both, or neither, and explain why - 112g, 118g, 106g

These measurements are not precise nor accurate, because they are not close enough to be accurate and they are not consistent either (not precise)

What is meant by standard temperature and pressure (STP)?

They are a set of conditions that we have deemed standard. The standard pressure is O°C or 273 K. The standard pressure is 1 atm.

Is the MO description more useful than the VB description? Why or why not?

They are useful for different reasons. MO is better for magnetism, bond order, and shows the energy levels. However, it is not as good for shape and polarity - this is where VB is better.

To test the precision and accuracy of weight scale in laboratory, you take a small block that is known to be exactly 1.000g and weigh it three times on the scale. Three measurements are reported as follows: 0.843g, 0.842g, and 0.843g. Is this scale precise, accurate, both, or neither? Explain your choice in 1 sentence.

This is scale is precise, but not accurate because it is not within 1% of the true value of 1.000g.

Medical implants and high-quality jewelry items for body piercings are frequently made of a material known as G23Ti or surgical-grade titanium. The percent composition of the material is 64.39% titanium, 24.19% aluminum, and 11.42% vanadium. What is the empirical formula of surgical-grade titanium?

Ti 64.39/47.87g (per mole) = 1.345 mol Ti /.2243 = 5.996 ~ 6, Al24.19/26.98g (per mole) = 0.8966 mol Al /.2243 = 3.997 ~4, V 11.42/50.94g (per mole) = 0.2243 mol V /.2243 = 1, Empirical Formula: Ti6Al4V

Why is there a negative sign in front of the P∆V term in ∆E = q - P∆V?

To ensure that the signs are correct for the expanding and contracting aspect to the ∆V = Vf-Vi equation. When it is expanding, we want the work value to be negative so we need to add a negative out front. When it is contracting, we want the work value to be positive so we need to add a negative out front.

How many total nodes will any given orbital have?

Total nodes is dependent on the principle quantum number. Total nodes is known by subtracting the principle quantum number by one.

There are also different 'families' of elements in the Periodic Table. List a transition metal, an alkali metal, a halogen, a noble gas, an alkaline earth metal, a nonmetal, a lanthanide, an actinide, and a metalloid in that order.

Transition: Mn, Alkali: Na, Halogen: F, Noble gas: Ne, Alkaline earth: Sr, Nonmetal: O, Lanthanide: Pm, Actinide: U, Metalloid: Sb

Why do so many transition metals form ions with a 2+ charge?

Transitions always lose their s electrons first, because full 4s is higher energy than 4d. When they lose the two electrons, they become a 2+.

Why do Trees 'drink' water, moving it from the ground to leaves in the air without muscles or movement of any kind.

Trees utilize capillary action (adhesion) which is caused by hydrogen bonding.

What is a Compound?

Two different elements are coming together to form a single substance.

The two isotopes of uranium, 238U and 235U, can be separated by diffusion of the corresponding UF6 gases. What is the ratio of the root-mean-square speed of 238UF6 to that of 235UF6 at constant temperature?

UrmsA/UrmsB = sqr. Root (MB/MA) = (.349/.352) = 0.996

Which of the following substances will be soluble in water, and which will be more soluble in nonpolar solvents? gasoline, crayons, vinegar, NaCl, SO2, CS2, Ca(OH)2

Water - vinegar, NaCl, SO2, Ca(OH)2. Nonpolar solvents - gasoline, crayons, CS2

Why does the plumbing in a house may burst if the temperature in the house drops below 0°C.

Water expands when it freezes, so it requires more room in the pipe.

In 5 sentences or less, describe what valence bond (VB) theory is.

Valence Bond theory is a theory of what bonds are. It explains that a bond is equivalent to an overlap in valence orbitals. It also hints at the orbitals involved in creating shapes.

Find the molecular masses of these flavors: Vanillin C8H8O3, Oil of cloves C10H12O2, Anise oil C10H12O, Oil of cinnamon C9H8O and which has the most moles of oxygen per mol?

Vanillin = 152.2, Oil of cloves =164.2, Anise oil = 148.2, Oil of cinnamon = 132.2 and Vanillin

Calculate the PV work done in the following situations (Note: 1 L·atm = 101.3 J) A researcher compresses a sample of gas from 25 L to 5.0 L by applying a pressure of 150 atm.

W= - (150atm) (5L-25L) = 3000Latm = 303900J

Calculate the PV work done in the following situations (Note: 1 L·atm = 101.3 J) A 30. mL balloon expands to 200. mL against an atmospheric pressure of 1.0 atm.

W= - (1atm) (.2L-0.03L) = -.17Latm = -17.22J

Calculate the PV work done in the following situations (Note: 1 L·atm = 101.3 J)Your lungs expand 750 mL against an external pressure of 4.0 atm as you take a breath from an oxygen tank while scuba diving.

W= - (4atm) (.75L) = -3Latm = -303.9J

Most automobile engines are cooled by water circulating through them and a radiator. However, the original Volkswagen Beetle had an air-cooled engine. Why might car designers choose water cooling over air cooling?

Water has a higher heat capacity.

Why is the specific heat capacity of water (Cp = 4.184 J/g-K) so much greater than that of ice (Cp = 2.03 J/g-K) or steam (Cp = 1.84 J/g-K)?

Water has strong hydrogen bonding, and also has vibrational and rotational motion.

What are quantum numbers and how are they related to the wave function?

Wave functions are identified by quantum numbers (n, l, ml - they act like coordinates).

What additional information is needed to determine a molecular formula if the empirical formula is known from combustion analysis?

We need to know the molecular mass to find the molecular formula.

What is scientific theory?

Well tested explanation of why a natural phenomenon is observed or why a scientific theory is true (why it is observed)

What does it mean for something to be 'quantized'?

When something is quantized, it means that it is made up of chunks rather than being continuous. That there are definite and discrete "quanta."

What is meant when two or more orbitals are said to be degenerate?

When two or more orbitals are "degenerate", it simply means that they have the same level of energy.

State the hybridization of the central atom, the molecular shape, and the bond angles for each of the following molecules or ions. Use < or > for bond angles where appropriate. XeF4, PF4 -, SbCl5

XeF4 - sp3d2 Square Planar 90 degrees, PF4 - - sp3d Seesaw <90 degrees and <120 degrees, SbCl5 - sp3d Trigonal Bipyramidal 90 degrees and 120 degrees

Freeze-drying is used to preserve food at a low temperature with minimal loss of flavor. It is accomplished by freezing the food and then lowering the pressure with a vacuum pump to sublime the ice. Must the pressure be lower than the pressure at the triple point of H2O?

Yes

Tetrafluoroethylene (C2F4) is the molecule from which teflon is made. Draw the Lewis Structure for C2F4. Does C2F4 contain polar bonds? If so, draw the dipole moment(s). Is it polar or nonpolar? Steric number for C? Bond angles? Hybridization?

Yes, Nonpolar, 3, Trigonal planar - 120 degrees, sp2

Give brief answers to the following questions about combustion analysis (1-3 sentences each). Is it important for combustion analysis to be done in an excess of oxygen? Why or why not?

Yes, because if there is not enough oxygen, we cannot have a complete combustion reaction.

Which elements below form monatomic ions with a charge of 2+?

Zinc, Cadmium and Period 2

Silver nitrate is used to 'plate' objects with silver (e.g., silver plated tableware or candlesticks). You learned in your favorite chemistry class that silver metal and zinc nitrate are produced when zinc metal is placed in a solution of silver nitrate, and you decide to apply this knowledge by attempting to plate your favorite spoon with silver. (FYI, this is not how silver plating is actually done...) You put your spoon along with 2.00 g zinc into a solution of silver nitrate containing 2.50 g silver nitrate. Write a balanced equation for the reaction that (you hope) happens. What will run out first? How many grams of silver will be formed, assuming the desired reaction goes to completion. Assuming this amount of silver is sufficient to plate the spoon, how many grams of each reagent will it take to replenish your setup and plate another spoon?

Zn + 2AgNO3(aq) -> 2Ag (s) + Zn(NO3)2 AgNO3 (2.5 AgNO3 x 2 molAg x 107.9g Ag) / (1.69.9gAg x 2mol AgNO3) = 1.588gAg 2.5g AgNO3 OgZn - Because you still have extra after the 0.481 which was used by the first

Paramagnetic or diamagnetic: Zn2+

[Ar]3d10 - Diamagnetic

Paramagnetic or diamagnetic: Ca

[Ar]4s2 -- Diamagnetic

Paramagnetic or diamagnetic: Li

[He]2s1 - Paramagnetic

Paramagnetic or diamagnetic: F-

[He]2s22p6 - Diamagnetic

Paramagnetic or diamagnetic: Ag+

[Kr]4d10 -Diamagnetic

Paramagnetic or diamagnetic: I

[Kr]5s24d105p5 - Paramagnetic

Paramagnetic or diamagnetic: Na+

[Ne]3s - Diamagnetic

What is the electroconductivity of Copper metal

a (partially filled valence

What is the electroconductivity of Silicon

c (semi-conductor)

Electrostatic forces are involved in holding together by a. ionic compounds b. Molecules c. crystal lattices c. all of the above

all of the above

What is the electroconductivity of Magnesium metal

b (overlapping bands

Hund's Rule

before you start doubling up the electron chart, you have to fill it out and give balance it

What is the electroconductivity of GaAs

c (semi-conductor)

Calculating the fuel value requires

converting the heat of combustion (kJ/mol) into grams and indicates what fuels produce the most energy

What is the electroconductivity of Silicon doped with phosphorus

d (n-type)

What is solid?

defined shape and volume

What is liquid?

defined volume but not defined shape

What is the electroconductivity of Silicon doped with gallium

e(p-type)

What is the electroconductivity of Sodium chloride

f (insulator)

Calculate frequency, calculate energy of 1000 photons, label part of EM spectrum

f = V / λ, E=hf=(hc/λ)1000, Gammarays - Xrays(10^-12) - UV (10^-8) - Visible (400-750 nm) - IR(10^-4) - Microwave (10) - Radiowaves (10^3) - Longwaves

Ernest Rutherford

gold foil with alpha particles they be pingin to the sides, found that there was a mass in the center of the atom that is positively charged. Neutrons - uncharged, Protons - pos, electrons - neg

Which of the following objects could be chiral (enantiomers -> have a non-superimposable mirror images)? golf club, spoon, glove, shoe, dead bolt key, screw, baseball, spiral seashell

golfclub, glove, show, dead bold key, screw, spiral seashell

In which set of elements on the periodic table are the p orbitals being filled? alkali metals, Halogens, Actinides, Lanthanides, transition metals

halogens

JJ Thompson's plum puddin model

he back spittin science positive blob with negative dots

JJ Thompson's cathode ray tube

he had two magnets and sent atoms through and discovered the electron because they were attracted to both sides. Magnetic fields = charge/mass ratio

What are the possible values of quantum number l when n = 4?

l= 0, 1, 2, 3

The second ionization energy of an atom is always

larger than its first ionization energy.

3.79 g of pure aluminum metal is cooled by water from 103.2 °C to 34.8 °C. The specific heat of aluminum is 0.890 Jg-1 °C-1 . If the water started out at 32.7 °C, how much water was used to cool the aluminum?

mAl CAl ΔT Al = - mw Cw ΔT w = (3.79g)(0.89)(34.8°C-103.2°C) = - mw(4.18)(34.8°C -32.7°C) = Mw=26.3g

For each of the 4 types of quantum numbers give the name of the quantum number, its letter/symbol, the range of its possible values, and explain in 1-3 sentences what property is related to each quantum number.

n: "The principal quantum number" which relates to the size of the electron orbital. Values range from 1 ≤ n, n = 1, 2, 3, ... l: "The angular quantum number" which relates to the shape of the electron orbital Values depend on n. 0 ≤ ℓ ≤ n − 1. Example: for n = 3, ℓ = 0, 1, 2 (s, p, d) Ml: "The magnetic quantum number" which relates to the spatial orientation of the electron orbital. Depend on the value of l. −ℓ ≤ mℓ ≤ ℓ. Example: ℓ = 2, mℓ = −2, −1, 0, 1, 2 Ms: "The magnetic spin quantum number or Quantum Number electron spin" relates to the direction in which the electrons within an orbital rotates. Values equate to −s ≤ ms ≤ s. Example: for an electron s = 1/2,so ms = −1/2, +1/2

Indicate whether the following transitions require absorption of energy or emission of energy: n=3 to n=1: n=2 to n=4?

n=3 to n=1: emission n=2 to n=4: absorption

Combustion analysis of an unknown gas gave an empirical formula of CH2. If 2.1 g of this gas occupies 3.1 L at 100. ºC and 0.50 atm, what is the molecular formula of this gas?

n=PV/RT = (.5 x 3.1) / (.08206 x 373.15) = 0.050mol MW = g/mol = 2.1g/0.050mol = 41.5g/mol CH2 = 14g/mol 41.6/14 = 2.96 ~ 3 C3H6

26.2g of an unknown gas occupies 5.3 L at 40.ºC and 742 torr. What is the molar mass of this gas? Further studies indicate that this gas is monotomic - which element do you suspect this gas is?

n=PV/RT = [(742/760)(5.3)] / (.08206)(313) = .201mol MW = g/mol = 26.2g/0.201mol = 130g/mol which would be Xe

A chemist burns one mole of C2H6 in oxygen and measures that 382 kJ of energy is released. How many grams of C2H6 must burn to raise the temperature of 39.0 L of water by 58.0°C? Assume the density of water to be 1.00 g/cm3.

nC2H6 ΔH combustionC2H6= - mw Cw ΔT w = NC2H6(-382000kJ/mol) = -(39000g)(4.18)(58°C) = 743gC2H6

The flavor of anise is due to anethole, a compound with the molecular formula C10H12O. Combustion of one mole of anethole produces 5541 kJ of thermal energy. If 0.950 g of anethole is combusted in a bomb calorimeter whose heat capacity (Ccalorimeter) is 7.854 kJ/°C, what is the change in temperature of the calorimeter?

ncombustionΔHcombustion = - Ccal ΔTCal, (0.00642mol) (-5541 kJ/mol) = -(7.854 kJ/°C)(ΔTcal), ΔTcal = 4.5°C

Ionization energies are always

positive

What is the sign of ∆G for the following processes? Remember, spontaneous reactions occur without being driven by an external source of energy. A broken cell phone is repaired

positive

What is the sign of ∆G for the following processes? Remember, spontaneous reactions occur without being driven by an external source of energy. You get an A in this course

positive

If the real weight of an object is 100 grams, state whether the following measurements are precise, accurate, both, or neither, and explain why - 99.7g, 100.1g, 100.2g

precise and accurate, because they are close and consistent

If the real weight of an object is 100 grams, state whether the following measurements are precise, accurate, both, or neither, and explain why - 110 g, 111 g, 110.5 g

precise but not accurate. They are close together but not near the original value

Assuming each of the following are pure liquids, for which is hydrogen bonding the dominant intermolecular force? A)Propanol b) Difluoromethane c) phosphine (PH3) d) hydrogen peroxide (HOOH) e) acetone (2-propanone) f) pentanal

propanol and hydrogen peroxide

Calculate the heat capacity of a calorimeter if the combustion of 4.663 g of benzoic acid produces an increase in temperature of 7.149°C.

qBenzoicAcid + qcal = 0 = qBenzoicAcid = - qcal = NBenzoicAcidΔHComustionBenzoicAcid = - Ccal ΔTCal (4.663g)(-26.38) = -Ccal(7.149°C) = 17.2 kJ/°C

What is the enthalpy change when 200.0 g of steam at 150 ºC is cooled to form ice at -50.0ºC?

qSteam= mscs∆Ts = (200g)(1.84J/gk)(-50C) = -18.4 kJ qcond= ncond∆Hcond = (200/18mol)(-40.67 kJ/mol) = -451.9kJ qwater= mwcw∆Tw = (20g)(4.184J/gk)(-100C) = -83.68J qfreeze= nfreez∆Hfreez = (200/18mol)(-6.01 kJ/mol) = -66.8kJ qice = miCi∆Ti = (200g0(2.03J/gk)(-50C) = -20.3 kJ qtotal = -641 kJ

Why is it necessary to know the heat capacity of a calorimeter?

qcal=CcalΔTcal. The heat capacity of the calorimeter is a significant part of calorimetric calculation and if it is ignored, this heat can drastically influence the results of the calculation.

The aromatic hydrocarbon cymene (C10H14) is found in nearly 100 spices and fragrances, including coriander, anise, and thyme. The complete combustion of 1.608g of cymene in a bomb calorimeter (Ccalorimeter = 3.640 kJ/°C) produced an increase in temperature of 19.35°C. How much thermal energy is produced during the complete combustion of one mole of cymene?

qcymene+qcal = 0, qcombustion = - qcal, ncombustionΔHcombustion = - Ccal ΔTCal, (.0012mol) ΔHcombustion = -(3.64 kJ/°C)(19.35°C), ΔHcombustion = -5869.5 kJ/mol

What is the enthalpy change when 100.0 g of ice at -30 ºC is warmed to form water at 50.0ºC?

qice= mici∆Ti = (100g)(203J/gk)(0+30C) = 6090 J, qmelt= n∆Hfus = (5.56mol)(6.01 kJ/mol) = 33.39kJ, qwater= mwcw∆Tw = (100g)(4.184J/gk)(50-0C) = 20920J ∆Htotal = 60.4kJ

During a strenuous workout, an athlete generates 233 kJ of thermal energy. What mass of water would have to evaporate from the athlete's skin to dissipate this energy?

qwater = -qbody = 233kJ, nw Δ=233kJ, Nw(40.7kJ/mol)=233kJ, Nw= 5.7 mol H2O x 18g = 103g H2O

Oxygen has a ____ first ionization energy than fluorine

smaller

Atomic radii increase moving down, because

the "n" or principle quantum numbers are increasing.

Atomic radii decreases as you go across the period, because

the valence electrons are being added to the energy level and protons are also being added.

If the real weight of an object is 100 grams, state whether the following measurements are precise, accurate, both, or neither, and explain why - 100.5 +/-.2 g

these measurements are precise and accurate, because the reported value is within 1% of the actual number

If the real weight of an object is 100 grams, state whether the following measurements are precise, accurate, both, or neither, and explain why - 105 g, 93 g, 102 g

these numbers are accurate, because their average is 100g, but they are not precise because they are too far apart

Greater wavelengths relate to

transitions which are small and far out.

Long straight chains of hydrogen and carbons

will have the highest boiling point and it will also be the most viscous at 20 degrees.

The breakdown of glucose in the cell begins with a process called glycolysis. Glycolysis is the main source of energy during anaerobic metabolism, a form of metabolism in which inhaled O2 does not play a role. Glycolysis occurs in a series of steps. One of the steps involves the conversion of fructose-6-phospate (F6P) to Fructose-1,6-diphosphate (FDP). This reaction is shown below along with the change in Gibb's free energy at standard conditions. F6P + PO43- = FDP + H2O

ΔG⊕ =+17 kJ Is this reaction spontaneous under standard conditions? Why or why not? No, because deltaG is greater than zero.

How many grams of methanol must be combusted to raise the temperature of 25.0 L of water by 2.25°C? Assume the density of water is 1.00 g/mL and use the following information, assuming the process is carried out at atmospheric (constant) pressure so ΔH° = q: 2CH3OH(l) + 3O2(g) → 2CO2(g) + 4H2O(l)

ΔH° = -1452.8 kJ nmeth ΔH combustionmeth= - mw Cw ΔT w = nmeth (-726400J/mol) = -(25000g)(4.18)(2.25°C) Nmeth = 0.324 moles x 32g = 10.4g methanol

The normal boiling point of ethanol is 78.3 ºC and the enthalpy of vaporization is 38.56 kJ/mol. What is ∆Ssys when 68.3 g of ethanol condenses at its normal boiling point and 1 atm?

ΔS = - n x Hvap/Tvap = ΔS = -(68.3/46)*38560 / (273+78.3) = -163

Describe two ways of calculating changes in entropy (∆S).

ΔS = ΔQ/ΔT and ΔG = ΔH - TΔS

Calculate the ∆S° value for the conversion of ozone to oxygen in the absence of Cl atoms, and compare it with the ∆S° value for the reaction with Cl. 2 O3(g) → 3 O2(g)

ΔS° reaction = ΣS° products - ΣS° reactants = 3(205.03) - 2(238.82)= 615.09 - 477.64 = 137.5 J/molK. The ΔS°rxn of the ozone is far greater than that of the interaction of ClO.

Louis deBroglie correctly postulated that matter has wavelike properties. What was the deBroglie wavelength of the baseball (0.145 kg) thrown at 108.1 mph (48.325 m/s) by Nolan Ryan in 1974, the fastest pitch recorded? Assuming the uncertainty in the measured speed was 5.5 x10-28 m/s, what was uncertainty in the ball's position as it passed the hitter? Did the fact that the baseball had wavelike properties add significantly to the challenge of hitting that baseball?

Δx =6.6 x 10-7 m The fact that the baseball had wavelike properties did not add significantly to the challenge of hitting that baseball. 9.46 x 10-26nm

Indicate whether q and w are positive or negative and calculate ∆E: A sample of gas releases 2.9 kJ of heat and the surroundings perform 830 J of P-V work on the gas.

∆E - -2.07 kJ, Q - -2.9kJ, w- +0.83 kJ

Indicate whether q and w are positive or negative and calculate ∆E: A reaction releases 150 kJ of heat and releases enough gaseous product to do 275 kJ of P-V work.

∆E - -425 kJ, Q - -150kJ, w- +275 kJ

Indicate whether q and w are positive or negative and calculate ∆E: Some gaseous reactants combine to form a liquid product, releasing 150 kJ of heat and causing the surroundings to perform 75 kJ of P-V work.

∆E - -75 kJ, Q - -150kJ, w- +75 kJ

Indicate whether q and w are positive or negative and calculate ∆E: 44 g of dry ice absorbs 25 kJ of heat. The resulting CO2 gos does 2.5 kJ of P-V work on the surroundings.

∆E - 22.5kJ, Q - +25kJ, w- -2.5 kJ

State whether q, w, and ∆E for the system are positive or negative: A reaction releases heat and produces several moles of gaseous product.

∆E - Negative, Q - Negative, w- Negative

State whether q, w, and ∆E for the system are positive or negative: Some water freezes and expands.

∆E - Negative, Q - Negative, w- Negative

State whether q, w, and ∆E for the system are positive or negative: A researcher compresses a gas sample and heats it up.

∆E - Positive, Q - Positive, w- Positive

State whether q, w, and ∆E for the system are positive or negative: A student heats up an ice cube until it melts (assume no volume change).

∆E -Positive, Q - Positive, w- Zero

Coupling of reactions can be used to make nonspontaneous reactions occur. For example, in glycolysis, some of the steps produce ATP rather than consume it. Given that the formation of ATP from ADP according to ADP + PO43- = ATP + H2O, with ΔG⊕ =+31 kJ, is not spontaneous, answer the following questions. What must the sign and magnitude be for any reaction that is coupled to this reaction to make it spontaneous (i.e. write an inequality). Could the conversion of phosphoenolpyruvate to pyruvate with ∆G=-62 kJ/mol be coupled to the ADP reaction above to create ATP? Explain why or why not.

∆G < -31 Yes because 31+ (-62kJ) = -31 kJ which is spontaneous

Describe 2 ways that ∆G can be calculated for a reaction.

∆G = ∆H - T∆S = ∆Grxn^°=∑n∆Gf°products - ∑n∆Gf° reactants

Use the thermodynamic values in Appendix 4 of your book to calculate ∆Grxn for the combustion of diamond at a temperature of 5000. ºC and determine whether it is spontaneous at that temperature.

∆G = ∆H - T∆S ∆Hrxn^°= [-393.4 kJ/mol] - [188kJ/mol + 0] = 395.4 kJ/mol ∆Srxn^°= [213.6 J/molK] - [2.43 J/molK+205J/molK] = 6.1 J/molK = 0.00617 kJ/molK ∆G= [395.4 kJ/mol] - [(5273K)(0.00617 kJ/molK)] = -428kJ/mol - spontaneous

Use the thermodynamic values in Appendix 4 of your book to calculate ∆Grxn for this conversion at 325 ºC and determine whether it is spontaneous at that temperature.

∆G = ∆H - T∆S ∆Hrxn^°= [-393.5 kJ/mol + (-217.3 kJ/mol)] - [-699.1 kJ/mol] = 88.3 kJ/mol ∆Srxn^°= [213.6 J/molK + (68.7 J/molK)] -[131 J/molK] = 0.1513 kJ/molK ∆G= [88.3 kJ/mol] - [(598K)(0.1513 kJ/molK)] = -2.18kJ/mol - spontaneous

Use the ∆Gºf values in Appendix 4 of your book to calculate ∆Grxn for the conversion of lead(II) carbonate into lead(II) oxide and carbon dioxide and determine whether it is spontaneous under standard conditions. PbCO3(s) → PbO(s) + CO2(g)

∆Grxn= [(-394.4 kJ/mol) + (-187.9 kJ/mol)] - [-625.5 kJ/mol] = 43.2 kJ/mol - non-spontaneous

One source of sulfuric acid aerosols in the atmosphere ("acid rain") is the combustion of high-sulfur fuels such as coal, which releases SO2 gas that then is further oxidized to SO3 in air:2 SO2(g) + O2(g) → 2 SO3(g) The SO3 then combines with water, forming fine droplets of sulfuric acid in the atmosphere SO3(g) + H2O(g) → H2SO4(ℓ) Use the appropriate ∆G°f data in Appendix 4 to calculate ∆G°rxn for both reactions and determine if they are spontaneous under standard conditions.

∆Grxn^° = [2(-371.1 kJ/mol)] - [2(-300.1kJ/molK)+ 1(0kJ/mol)] = -142kJ/mol - spontaneous ∆Grxn^° = [(-689.9 kJ/mol)] - [-371.1 kJ/molK)+ (-237.13 kJ/mol)] = -81.67 kJ/mol - spontaneous

Calculate ∆E and ∆H for the following situations: A sample of gas releases 9.2 kJ of heat. It is also compressed from 30. L to 5.0 L under a constant pressure of 3.0 atm.

∆H = -9.2kJ ∆E = -9.2kJ - (3)(5-30L) ∆E = -9.2kJ + 7.6k = -1.6kJ

Calculate ∆E and ∆H for the following situations: A reaction releases 150 kJ of heat and releases enough gaseous product expand to 275 L from 5 L against 2.5 atm of pressure.

∆H = q = -150kJ ∆E = -150kJ - (25atm)(275-5L) ∆E = -150kJ- 68.4kJ = -218 kJ

Calculate ∆E and ∆H for the following situations: A sample of gas absorbs 25 kJ of heat and expands 25 L against 1.0 atm of pressure.

∆H = q = 25kJ ∆E = q-P∆V ∆E = 25-(1)(25L) ∆E = 25-2.5kJ = 22.5kJ

Calculate ∆E and ∆H for the following situations: A reaction that absorbs 75 kJ of heat and releases enough gaseous product to expand 150 L against an external pressure of 5.0 atm.

∆H = q = 75kJ ∆E = 75kJ - (5atm)(150L) ∆E = 75kJ -76kJ = -1 kJ

Use the bond enthalpies in the table above to estimate ∆Hrxn for the following reaction: chlorine gas reacts with ethene to form 1,2-dichloroethane

∆Hrxn = [1(242kJ/mol) +4(413 kJ/mol) + 1(614kJ/mol)] - [2(328 kJ/mol) + 1(348 kJ/mol) + 4(413kJ/mol)] = -148 kJ

Use bond enthalpies to estimate ∆Hrxn for the Haber process below in which nitrogen from the air is 'fixed' into a usable form. Compare this with ∆Hrxn calculated from ∆Hºf , which is -46.19 kJ per mol of NH3(g). If there is a difference, why is there a difference? Which do you expect to be more accurate and why? N2(g) + 3H2(g) → 2NH3(g)

∆Hrxn = [1(941kJ/mol) +3(436 kJ/mol)] - [6(391)kJ/mol)] = -97 kJ/2= -48.5 kJ/mol NH3 ∆Hf is more accurate because the bond enthalpies will be different (a CH bond in one molecule will be different in one atom from that of another.)

Fertilizer (ammonium nitrate) and fuel oil (a mixture of long-chain hydrocarbons similar to decane, C10H22) can form an explosive mixture. Determine the enthalpy change of the following explosive reaction by using the appropriate enthalpies of formation from Appendix 4 in your book and ∆H°f,C10H22 = 249.7 kJ/mol. 3NH4NO3(s) + C10H22(ℓ) + 14O2(g) → 3 N2(g) + 17 H2O(g) + 10 CO2(g)

∆Hrxn = [3(0kJ/mol) +17(-241.8 kJ/mol) + 10(-393.5)] - [3(365.6 kJ/mol) + 1(249.7 kJ/mol) + 14(0kJ/mol)] = -7198 kJ

Use the bond enthalpies in the table above to estimate ∆Hrxn for the reaction of ethane with oxygen gas to form carbon dioxide and water vapor.

∆Hrxn = Σn∆Hbroken - Σn∆Hformed∆Hrxn = [6(413kJ/mol) +1(348 kJ/mol) + 3.5(495kJ/mol)] - [4(799 kJ/mol) + 6(463 kJ/mol)] = -1415.5kJ/mol ethane

Use the thermodynamic values in Appendix 4 of your book to predict the temperature at which hydrogen peroxide boils: H2O2(l) -> H2O2(g)

∆Hrxn^°= [-136.1 kJ/mol - (-187.8 kJ/mol)]= 51.7 kJ/mol ∆Srxn^°= [232.9 J/molK - (109.6 J/molK)] = 123.3 J/molK = 0.1233 kJ/molK Tfus= ∆H/∆S = 51.7kJ/mol/0.1233kJ/molK = 419 K

Use the thermodynamic values in Appendix 4 of your book to predict the temperature at which methanol (CH3OH) boils.

∆Hrxn^°= [-201.2 kJ/mol - (-238.6 kJ/mol)]= 37.4 kJ/mol ∆Srxn^°= [237.6 J/molK - (126.8 J/molK)] = 110.8 J/molK = 0.1108 kJ/molK Tfus= ∆H/∆S = 37.4 kJ/mol/0.1108 kJ/molK = 337.5 K

What are the signs of ∆S, ∆H, and ∆G for making ice cubes in the freezer?

∆S - negative, ∆H - negative, ∆G - negative

What are the signs of ∆S, ∆H, and ∆G for the formation of dew on a cool night?

∆S - negative, ∆H - negative, ∆G - negative

What are the signs of ∆S, ∆H, and ∆G for the sublimation of dry ice (solid CO2) at 25°C?

∆S - positive, ∆H - positive, ∆G - negative

Mercury is a liquid at room T and freezes at -38.9 ºC. What is the entropy change when 50.0g mercury freezes if its enthalpy of fusion is 2.29 kJ/mol?

∆S = q/T = n∆H/T = (.25mol)(-2.29)/234.1K = -0.0024 kJ/K

A particular reaction releases 25 kJ of heat into the surroundings, which are 27 ºC. If this reaction is spontaneous, how does this limit the possible values for ∆Srxn?

∆S > -.0833 (25kJ/300K)

A particular reaction is spontaneous and has ∆Srxn = -163 J/K. What must be true about ∆Ssurr?

∆Ssurr > 163 J/K

Adding sidewalk deicer (calcium chloride) to water causes the salt to dissolve and the temperature of the water to increase. If solid CaCl2 is the system, what are the signs of ∆Ssys, ∆Ssurr, and ∆Suniv?

∆Ssys +, ∆Ssurr +, ∆Suniv +

Ice cubes melt in a glass of lemonade, cooling the lemonade from 10.0°C to 0.0°C. If the ice cubes are the system, what are the signs of ∆Ssys, ∆Ssurr, and ∆Suniv?

∆Ssys +, ∆Ssurr -, ∆Suniv +

Assuming the box from part "a" is a cube with all sides of equal length, is the side of the box closest in length to the diameter of the Sun (1,400,000 km), the diameter of the Earth (13,000 km), the length of the state of Texas (1200 km), the length of Utah lake (39 km) or the width of the BYU Marriott Center (120 m)?

∛(1.3x109km3) =1100km. This means that the length of the box would almost be the length of Texas.

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