CHEM

How many unpaired electrons does Ca2+ have? Calcium is element number 20. Please, note, it is the ion and has lost 2 electrons.

0

10 out of 10 points Determine the number of valence electrons in the element Lithium (Li, element

1

Calculate the molecular or formula weight of nicotine, whose formula is C10H14N2. The atomic symbols for the elements are 6C12, 1H1, 7N14.

162 g/mol

Calculate the temperature at which 1.5g of O2 (32 g/mol) has a pressure of 740 mmHg in a 1.0L container. K = oC + 273; 1 atm = 760 mmHg. R = 0.08206 Latm/Kmol PV = nRT

253K

What are the correct units for Molar Mass?

g/mol

Which solvent will ethanol, CH3CH2OH dissolve in?

h20

The boiling point of H2 is -252.9oC. Will H2 be a liquid or gas at -254 oC

liquid

Is Francium (87Fr223) a metal, or a nonmetal? You can use any periodic table you wish for this problem.

metal

Isotopes are atoms of the same element that have different numbers of:

neutrons

Which of the following will have the highest boiling point? The first atom listed is the central atom.

nh3

Water has the chemical formula H2O (H = hydrogen; O = Oxygen) while hydrogen peroxide has the chemical formula H2O2. They are both composed of hydrogen and oxygen atoms in different ratios. Will water and hydrogen peroxide have identical chemical and physical properties?

no they will not have identical properties

In the picture, what happens to the system and surroundings over time?

nothing, stay the same

atomic number equal to

number of protons

Which of these molecules has a lone pair that helps determine the shape

ph3

Define heat

the flow of energy caused by a temperature difference

Based on the equation below, classify the change as physical or chemical (the spheres represent atoms, different shading indicates different types of atoms): CH4(g) + 2O2(g) → CO2(g) + 2H2O(g)

chemical change

Will a vessel containing a reaction that has an ∆Hrxn = +8,121 kJ/mol be warm or cold to the touch?

cold

How many valence electrons does nitrogen have (N is element 7)

5

There are exactly 60 seconds in a minute, there are exactly 60 minutes in an hour, there are exactly 24 hours in a mean solar day, and there are 365.24 solar days in a solar year. Find the number of minutes in a solar year

5.2595 x 105 minutes

Determine the theoretical yield of HCl if 60.0 g of BCl3 and 37.5 g of H2O are reacted according to the following balanced reaction. BCl3 = 117.16 g/mol; H2O = 18g/mol; HCl = 36 g/mol. BCl3(g) + 3 H2O(l) → H3BO3(s) + 3 HCl(g)

56.0 g HCl

Which element has the highest nuclear charge? Rubidium (37Rb), Strontium (38Sr), Cesium (55Cs), Barium (56Ba) or Chlorine (17Cl)

Ba

Determine the molecular formula of a compound that has a molar mass of 183.2 g/mol and an empirical formula of C2H5O2. Carbon is element 6; Hydrogen is element 1; Oxygen is element 8.

C4H10O4

In 1645 Evangelista Toricelli conducted a series of experiments using a device much like that shown below. Using this device, he measured a distance between the mercury in the vessel and the mercury in the tube of approximately 760 mmHg (or 1 atm) at sea level. Using this data, he generated the hypothesis that the air has a pressure, and that the higher one moved in the atmosphere the lower the pressure would be. The way to test this was to take measurements at different elevations (altitudes) and compare them to those at sea level. Assuming the hypothesis is correct, will the amount of mercury in the tube increase, decrease or stay the same at higher altitudes?

Decrease (the number will be less than 760 mmHg)

According to Kinetic Molecular Theory, why can gases be compressed into small volumes?

Gas molecules are relatively far apart compared to the size of atoms/molecules

which statement is FALSE

The emission spectrum of a particular element is never the same from one experiment to the next and cannot be used to identify the element.

What element is undergoing oxidation (if any) in the following reaction? Carbon is element 6; Hydrogen is element 1; Oxygen is element 8. CH4(g) + 2 O2(g) → CO2(g) + 2 H2O(g)

c

Which of the following has the strongest dispersion forces? All are hydrocarbons

c6h14

What is the shape (or molecular geometry) around the nitrogen in methylamine? The molecule is shown below.

trigonal pyramidl

Is hydrogen cyanide a polar molecule (rephrased: does it have a net dipole moment?)? The molecule is shown below.

yes it is polar

Pure platinum has a density of 21.4 g/mL at 20oC. A block of platinum is sold at auction, and the buyers find that the block weighs 1.2x102 grams and has a volume of 5.61 mL at 20 oC. Is the block of platinum pure?

yes its pure

Is the following a valid Lewis structure for CH2Cl2?

yes, its a valid lewis structure

The main engines of the Space Shuttle burn hydrogen to produce water. How much heat (in kJ/mol) is associated with this process if 1.32 x 105 kg of liquid H2 (2 g/mol) is burned? 1,000 g = 1 kg and 1,000 J = 1 kJ

-1.89x1010 kJ/mol

The average temperature of the universe is 2.735K. What is this temperature in oC? K = oC + 273

-270.3 degrees c

A 425-mL sample of O2 gas was collected at 742.3 mmHg. What would the pressure be in mmHg if the gas were allowed to expand to 975 mL at constant temperature and constant moles of gas? (1,000 mL = 1L) P1V1 = P2V2

324 mmHg

Which subshells is described by the quantum numbers n=5, l=2, and ml= -1.

5d

Water is far more abundant than petroleum. Why can't the decomposition of water into its elements be used to run an automobile? 2H2O → 2H2 + O2 ∆H = +483.6 kJ/mol

The reaction is endothermic and couldn't be used to run an engine.

anion

atom gained an electron

Which curve best represents the relationship between the volume of an ideal gas and its pressure for a certain number of moles of gas at a constant temperature? Assume the x- and y-axis intercept is the low point (to clarify, pressure increases from left to right while volume increases from bottom to top).

curve A

Which of these has the highest first ionization energy? A periodic table might be useful in answering this question.

flourine

Give the change in condition to go from a liquid to a gas.

increase heat

gas

indefinite shape and indefinite volume

Which element corresponds to this mass spectrum?

indium

Give the spectator ions for the reaction that occurs when aqueous solutions of K2S and Fe(NO3)2 are mixed. K2S(aq) + Fe(NO3)2(aq) → K(NO3)(aq) + FeS(s)

k+ and N03-

is the figure below a valid orbital diagram for the valence electrons in bismuth (element 83)? To clarify, are the electrons placed in the 6s and 6p orbitals correctly?

no, not correct

The shape of a molecule with four bonding pairs and no lone pairs around the central atom is? Assume the four bonding pairs are each a single bond.

tetrahedral

What is the concentration in Molarity (M) of 0.585 moles of HCl in 0.15L of solution? (M = mol/L; 1000 mL = 1L)

3.9 M

How many electrons are in an ion of calcium, Ca2+ (the atomic symbol for calcium is 20Ca40)?

32 electrons

Give the mass percent of carbon in C14H19NO2. Carbon is element 6; Hydrogen is element 1; Nitrogen is element 7; and Oxygen is element 8.

72.07%

What is the energy of a photon of light with a wavelength of 247 nm?

8.05 x 10-19J

Read temperature with the correct number of significant figures.

87.200 c

How many molecules of N2O4 are in 76.3 g N2O4? The molar mass of N2O4 is 92.02 g/mol. 1 mol = 6.02 x 1023 molecules.

4.99 × 1023 N2O4 molecules

Identify the element that has an electronic configuration of [Kr]5s24d4

42Mo

Give the set of three quantum numbers that could represent the electron gained when an atom of fluorine (9F) gains an electron to form the fluoride ion (F-). In other words, what are the quantum numbers for the orbital that electron is going into? (Hint: Identify the shell and subshell that fluorine is in (for example, it might be 2p)...what are the quantum numbers for that shell and subshell?

. n = 2, l = 1, ml = 1

What number must be placed in front of AlPO4 to balance the reaction? (Hint: Balance the polyatomic ions as units. For example, if it is C2H3O2 in the reactants and C2H3O2 in the products, you can simply treat it as single unit instead of individual atoms. Al(C2H3O2)3 + (NH4)3(PO4) → Al(PO4) + (NH4)(C2H3O2)

1 or no number

Determine the molarity of a solution formed by dissolving 97.7 g LiBr in enough water to yield 750.0 mL of solution. The molar mass of LiBr is 87 g/mol. 1,000 mL = 1L Molarity (M) = mol/L

1.50 ML

Consider the following balanced reaction. How many grams of water are required to form 75.9 g of HNO3? The molar masses are as follows: H2O = 18.02 g/mol, HNO3 = 63.02 g/mol. 3 NO2(g) + H2O(l) → 2 HNO3(aq) + NO(g)

10.9 g h20

Which of the following have their valence electrons in the same shell? To clarify, same shell means the same principal quantum number (all electrons in n=1, for example). All subshells within a principal quantum number are part of the same shell.

11Na, 12Mg, 18Ar

A 14.01 g sample of N2 reacts with 5.02 g of H2 to form ammonia (NH3). If ammonia is the only product, what mass of ammonia is formed? (This is a limiting reagent problem).

17.01 g

How many valence shell electrons does an atom of Radium (88Ra) have?

2

In Canada, atmospheric pressure during weather reports is announced in the units of pascals. What is 2.53 atm in pascals? 1atm = 101,325 Pa

2.56x105Pa

How many grams of Li3N can be formed from 1.75 moles of Li? Assume an excess of nitrogen. Molar Mass Li3N is 35 g/mol; Atomic Mass N is 14 g/mol. 6 Li(s) + N2(g) → 2 Li3N(s)

20.3 g Li3N

Calculate the molar mass of Al(C2H3O2)3. Aluminum is element 13; Carbon is element 6; Hydrogen is element 1; Oxygen is element 8.

204.13g/mol

Methane and oxygen react to form carbon dioxide and water. What mass of water is formed if 9.6 g of methane reacts with 38.4 g of oxygen to produce 26.4 g of carbon dioxide? (Hint: Law of Conservation of Matter) CH4 + 2O2 → CO2 + 2H2O

21.6 g

Determine the volume of an object that has a mass of 455.6 g and a density of 19.3 g/mL (please remember 1 mL = 1 cm3 so they can be used interchangeably).

23.6 mL

How many orbitals (ml) are in the 2p subshell

3

What is the charge on the Co ions in Co2O3? Cobalt is element 27 and Oxygen is element 8.

3+

Calculate the frequency of red light that has a wavelength of 873 nm if the speed of light is 3x108m/s. 1 nm = 1x10-9 m.

3.44x1014 s-1

What would the volume of 1 mole of an ideal gas be at 22oC and 748.8 mmHg? K = oC + 273; 1 atm = 760 mmHg. R = 0.08206 Latm/Kmol

3.65x103L

10 out of 10 points Write a balanced equation to show the reaction of aqueous aluminum acetate with aqueous ammonium phosphate to form solid aluminum phosphate and aqueous ammonium acetate.

Al(C2H3O2)3(aq) + (NH4)3(PO4)(aq) → AlPO4(s) + 3 (NH4)(C2H3O2)(aq)

One way of testing for water in a gasoline tank is to drain a little bit of gasoline from the bottom of the tank and look for two layers. Why are two layers an indication that water is in the gas tank? The main component of gasoline is octane (C8H18).

Gasoline is nonpolar and water is polar so they do not mix

greenhouse gas

Greenhouse gases allow visible light to pass through and warm the Earth's surface, and prevent heat energy from radiating back out into space.

Identify the compound with ionic bonds.

KCl (19K; 17Cl)

The molecule Thymine, one of four bases found in DNA, has the structure shown below. Which type of atom is missing a lone pair (or lone pairs) of electrons?

N

Predict the products when lead(II) nitrate reacts with NaCl. Pb(NO3)2(aq) + NaCl(aq) →

Predict the products when lead(II) nitrate reacts with NaCl. Pb(NO3)2(aq) + NaCl(aq) →

Give the net ionic equation for the reaction that occurs when aqueous solutions of lithium sulfide, Li2S, and copper(II) nitrate, Cu(NO3)2, are mixed. Li2S(aq) + Cu(NO3)2(aq) → 2Li(NO3)(aq) + CuS(s)

S2-(aq) + Cu2+(aq) → CuS(s)

Consider the phase diagram shown. Choose the statement below that is TRUE.

The line separating the solid and liquid phases indicates that both solid and liquid are present at the same time in the sample at equilibrium.

Does the following chemical reaction obey the law of conservation of matter (the amount of reactants and products is listed below the equation; the species in parentheses are the elements or compounds represented by the names): Gold (Au) + Cyanide (CN-) → Gold Cyanide (Au(CN)4-) [4.78g] [4.78g] There are 4.78 grams of reactants and 4.78 grams of products.

Yes, it obeys the law of conservation of matter

In general, ionization energies (IEs) decrease from top to bottom in the periodic table (those at the bottom of a column have lower values). See the Figure below. Which of the following is the best explanation for this observation?

a. As you move down a column you start a new principal quantum number (e.g., move from n=1 to n=2) and hence a new shell.

What are some problems/concerns over burning fossil fuels?

all of the above

Equal amounts (moles) of N2, O2, Ar, and CO2 are placed into a container. Which gas produces the Lowest partial pressure when the temperature and volume are held constant?

all produce the same partial pressure

Which of the following is TRUE if ΔEsys = -100 J?

b. The system is losing 100 J, while the surroundings are gaining 100 J.

As the distance between the electron(s) and nucleus increases, what happens to the force of attraction between them?

decreases

A Lewis structure for SiO2 is shown to the right. List the strongest intermolecular force present in this molecule.

dispersion forces

The intermolecular force that exists in all atoms and molecules is known as

dispersion forces

Predict whether the following reaction would be endothermic or exothermic. You do not need an enthalpy to predict the answer, look at the identity of the reactant(s) and product(s). CO(g) → C(g) + O(g)

endothermic

True or False, Matter is destroyed in chemical reactions

false

True or False. The average kinetic energy of gas samples can be obtained by measuring their Volumes.

false

True or False. The partial pressure of a gas depends on the identity of the gas (for example, H2 and O2 would result in different pressures even if all conditions are identical). (Hint: Looking at the simple gas law for how pressure relates to moles might help answer this).

false

The same quantity of heat is added to equal numbers of moles of CCl4(l) and H2O(l). The temperature increases more in CCl4 than H2O. Which has the highest heat capacity?

h20

Using logic, Leucippius and Democritus proposed that all matter must be composed of tiny, indivisible particles. Using modern scientific terminology, we would call this:

hypothesis

In the molecule shown below, which atom(s) has the partial negative (δ-) charge? A table of electronegativities is located in the class notes.

oxygen

Which of the following quantum numbers describes the size and energy of an orbital?

principal quantum number (n)

How many protons, neutrons and electrons are in an atom of the fictitious element Westmontium, 413Wt197?

protons = 197, neutrons = 216, electrons = 197

Identify the orbital

s

What are the possible subshells for n = 1?

s

Identify the element whose photoelectron spectrum is shown below.

scandium

Identify the shortest bond.

triple covalent bond

True or false. The lower (or smaller) the wavelength the higher (or larger) the frequency.

true

Molecules (also called compounds) can be described as:

two or more atoms chemically joined together