CHEMISTRY FINAL
In Bohr's atomic theory, when an electron moves from one energy level to another energy level more distant from the nucleus:
Energy is absorbed.
According to Avogadro's law:
Equal moles of gases occupy the same volume at constant temperature and pressure.
Order the elements S, Cl, and F in terms of increasing atomic radii.
F, Cl, S
Because water is made of two elements oxygen and hydrogen, it lies under the category of impure substances.
False
While balancing a chemical equation the subscripts of the compounds are changed to make their numbers equal on both sides
False
Choose the molecule with the strongest covalent bond.
HF
In which of the following does nitrogen have the highest oxidation state? (Note: this question has double points 1.6 unlike others)
HNO3
The rate constant for the beta decay of thorium-234 is 2.876 × 10-2 / day. What is the half-life of this nuclide?
24.10 days
What volume of 0.4M NaOH solution is required to react completely with 25.0 mL of 2.2 M H2SO4? The required chemical equation is 2NaOH + H2SO4 Na2SO4 + 2H2O
275 mL
A gas sample is held at constant pressure. The gas occupies 3.62 L of volume when the temperature is 21.6°C. Determine the temperature at which the volume of the gas is 3.43 L.
279 K
Express the following in scientific notation: 30,005,000
3.0005 × 107
A sample of ammonia (NH3) has a mass of 89.9 g. How many molecules of ammonia are in this sample?
3.18 × 1024 molecules
Write 0.000 000 33 in scientific notation.
3.3 × 10-7
Calculate the density of a mass of 120 grams and having the volume 36 cm3.
3.33 g/cm3
For combustion reaction of butane C4H4 (g) + O2 (g) → 4CO2 (g) + 2H2O (g) at 298 K and 1 atm pressure, ΔH° = -2877 kJ/mol. What will be the heat released when 6.05 g of butane is combusted under these conditions?
300k J
30.0 mL of pure water at 282 K is mixed with 50.0 mL of pure water at 339 K. What is the final temperature of the mixture? (Hint: mLs can be used as grams since the density of water is 1.0 g/mL, both waters will obviously have the same specific heat and are cancelled in the equation).
318 K
Identify the true precipitates (insoluble compounds make true precipitates) in any given water solution. I. Fe(OH)3(s) II. (NH4)2CO3 (s) III. CaSO4 (s) IV. AgCl (s) V. MgCl2 (s)
1 ,3 ,4
C2H5OH(l) + 3O2(g) → 2CO2(g) + 3H2O(l), ΔH = -1.37 × 103 kJ For the combustion of ethyl alcohol as described in the above equation, which of the following is true? I. The reaction is exothermic. II. The enthalpy change would be different if gaseous water was produced. III. The reaction is not an oxidation-reduction one. IV. The products of the reaction occupy a larger volume than the reactants.
1 and 2
Which of the following is the highest energy orbital for a silicon atom?
3p
A 6.51-L sample of carbon monoxide is collected at 55°C and 0.816 atm. What volume will the gas occupy at 1.05 atm and 25°C?
4.60 L
Electron capture transformsK into what nuclide?
40 18Ar
Consider a certain type of nucleus that has a rate constant of 2.96 × 10-2 min-1. Calculate the time required for the sample to decay to one-fourth of its initial value.
46.8 min
Calculate the root mean square velocity for the O2 molecules in a sample of O2 gas at 11.8°C. (R = 8.3145 J/K mol)
471.1 m/s
A sample of wood from an Egyptian mummy case gives a count of 8.7 cpm/gC (counts per minute per gram of carbon). How old is the wood? (The initial decay rate ofis 15.3 cpm/g C, and its half-life is 5730 years.)
4888 yr
Write 540 000 in scientific notation.
5.4 × 105
How many protons, neutrons, and electrons, respectively, are present in the anion formed by one atom of 125I? (Hint: first make the correct anion of I)
53, 72, 54
232Th decays to 208Pb. How many alpha decays are involved in this decay series?
6
A p orbital consists of ______ sub-orbitals.
6
Balance this equation using the smallest possible integers, NO + NH3 → Ν2 + H2O. What is the coefficient of the water after balancing?
6
A gaseous mixture containing 1.5 mol Ar and 3.5 mol CO2 has a total pressure of 8.6 atm. What is the partial pressure of CO2?
6 atm
Ammonia can be made by reaction of water with magnesium nitride as shown by the following balanced equation: Mg3N2(s) + 6H2O(l) → 3Mg(OH)2(s) + 2NH3(g) If this process is 81% efficient, what mass of ammonia can be prepared from 23.0 kg magnesium nitride?
6.3 kg NH3
Balance the following chemical equation for the combustion of propanol, C3H7OH, using the smallest whole number coefficients and use the balanced equation to answer the following question. C3H7OH + O2 → CO2 + H2O What is the coefficient of O2?
9
A chemical reaction produced 10.1 cm3 of nitrogen gas at 23 °C and 746 mmHg. What is the volume of this gas if the temperature and pressure are changed to 0 °C and 760 mmHg?
9.14 cm 3
For which of the following reaction(s) is the enthalpy change for the reaction not equal to ΔHf° of the product? I. 2H(g) → H2(g) II. H2(g) + O2(g) → H2O2(l) III. H2O(l) + O(g) → H2O2(l)
1 and 3
Which of the following names for the given formula are correct? 1.) S2- = sulfide ion 2.) NH4Cl = nitrogen hydrogen chloride 3.) BaO = barium oxide 4.) SO2 = sulfur oxide
1 and 3
What is the scientific notation of the following number? 0.001020
1.02 × 10-3
Calculate the ratio of the effusion rates of N2 and N2O. (Hint: Find the molar masses of the given gases)
1.25
How many moles of hydrogen sulfide are contained in a 44.4-g sample of this gas?
1.30 mol
A sample of a gas occupies a volume of 2.62 liters at 25 °C and 1.00 atm. What will be the volume at 50.0 °C and 2.00 atm?
1.42 L
What is the specific heat capacity of a metal if it requires 169.6 J to change the temperature of 15.0 g of the metal from 25.00°C to 32.00°C?
1.62 J/g°C
Human body temperature is about 309 K. If a person has a lung capacity of 2.1 L, what volume of air at 277 K must they breathe in to fill the lungs?
1.88 L
A balloon has a volume of 1.80 liters at 24.0°C. The balloon is heated to 48.0°C. Calculate the new volume of the balloon.
1.95 L
How many electrons in an atom can have the quantum numbers n = 4, l = 2?
10
1.004 x 105 in normal notation will be
100400
How many grams of NaOH are contained in 5.0 × 102 mL of a 0.81 M sodium hydroxide solution?
16 g
Consider a planet where the temperature is so high that the ground state of an electron in the hydrogen atom is n = 4. What is the ratio of ionization energy for hydrogen on this planet compared to that on Earth?
16:1
Which of the following is an incorrect designation for an atomic orbital?
1p
The complete electron configuration of tellurium (Te) is
1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s2 4d10 5p4
How many decimal places should we put in the answer to the following calculation? 0.0025002 + 1.204 + 2.12
2
How many electrons does germanium (Ge) have in its 4p orbital?
2
How many of the following molecules-SF2, SF4, SF6, SiO2-are polar?
2
How many resonance structures can be drawn for the molecule O3?
2
Indium reacts with chlorine to form InCl3. In the balanced equation for this reaction, the coefficient of the indium trichloride is
2
What is the subscript of rubidium in the formula of rubidium sulfate?
2
What should be the number of significant figures in the calculation of this: 4.546 ÷ 2.3 × 11.3?
2
For an ideal gas, which pairs of variables are inversely proportional to each other (if all other factors remain constant)? 1. P and T 2. V and P 3. n and P 4. V and T
2 only
Which of the following is single replacement reaction? I. CO2 + 2LiOH → Li2CO3 + H2O II. Cu + 2AgNO3 → Cu(NO3)2 + 2Ag III. PCl3 + Cl2 → PCl5 IV. FeCl2 + 2NaOH → Fe(OH)2 + 2NaCl
2 only
2.5 picometer = how many meters?
2.5 x 10-12 m
The given symbol (40 is the top number)(20 is the bottom number) 4020Ca2+ has
20 protons, 20 neutrons, and 18 electrons
A sample of chemical X is found to contain 5.0 grams of oxygen, 10.0 grams of carbon, and 20.0 grams of nitrogen. The law of definite proportion would predict that a 75 gram sample of chemical X should contain how many grams of carbon?
21 grams. Feedback: If 35 (5 + 10 + 20) grams of the compound has has 10 grams carbon, how many grams carbon would 75 grams of the compound have? (10/35) × 75 = ?
Ammonium sulfate, (NH4)2SO4, contains what percent nitrogen by mass?
21.2%
Hydrogen fluoride (HF, a liquid) exhibits stronger hydrogen bond interactions than ammonia (NH3, a gas).
TRUE
Intermolecular forces are weaker than intramolecular forces.
TRUE
The scientific notation of the number 2144478 is 2.144478 × 10-6
TRUE
The volume of a 100 g piece of pure iron is twice as great as the volume of a 50 g piece of pure iron.
TRUE
When a system performs work on the surroundings, the work is reported with a negative sign.
TRUE
Ionization energy is higher for Ca+ compared to Ca.
TRUE?
Which of the following is in accordance to Graham's law?
The rates of effusion of gases are inversely proportional to the square roots of their molar masses
In the reaction C(s) + O2(g) → CO2(g) carbon is __________.
The reducing agent
A reducing agent is an electron donor.
True
According to MO theory, F2 should be diamagnetic.
True
As atomic mass increases, the proton/neutron ratio of stable nuclides decreases.
True
H2PO3 is a diprotic acid
True
Which of the following is not a SI unit of the property it measures?
Volume-liter
Which of the following equations correctly represents the process involved in the electron affinity of an element X?
X(g) + e- => X-(g) This is basically the definition of electron affinity which is energy change while adding one electron to a gaseous atom to make it a negative ion. You should choose an answer which shows an addition of an electron to make an anion.
In the reaction Zn + H2SO4 → ZnSO4 + H2, which, if any, element is oxidized?
Zinc
Select the correct electron configuration for Cu.
[Ar]4s1 3d10
When a water molecule forms a hydrogen bond with another water molecule, which atoms are involved in the interaction?
a hydrogen from one molecule and an oxygen from the other molecule
Which of the following is indicative of the existence of strong intermolecular forces of attraction in a liquid?
a very low vapor pressure
The property of volume is a measure of
how much space the object occupies
The correct name for FeO is
iron (II) oxide
Which cannot be the unit of density?
lb/m
Which of the following pairs is incorrect?
phosphorus pentoxide, P2O5
Which of the following processes decreases the atomic number by one?
positron production and electron capture
Which of the following statements correctly describes the signs of q and w for the following exothermic process at P = 1 atm and T = 370 K? H2O(g) → H2O(l)
q is negative, w is positive.
In the reaction 2Cs(s) + Cl2(g) → 2CsCl(s), Cl2 is
the oxidizing agent
An element with the electron configuration [Xe] 6s24f145d7 would belong to which class on the periodic table?
transition elements
Which of the following has the types of electromagnetic radiation arranged in order of decreasing frequency?
ultraviolet, visible, infrared
The measure of resistance to flow of a liquid is
viscosity
Use the kinetic molecular theory of gases to predict what would happen to a closed sample of a gas whose temperature and the volume both are increased simultaneously.
Its pressure would roughly remain the same
Select the spectator ions for the following reaction, Pb(NO3)2 + 2 KCl → PbCl2 + 2 KNO3
K+(aq), NO3-(aq)
Which of the following salts is insoluble in water?
K2CO3 CaCl2 Pb(NO3)2 Na2S All of the salts given are soluble in wate
Choose the compound with the most ionic bond from among the options provided
KF
The scientist who discovered the law of conservation of mass and is also called the father of modern chemistry is
Lavoisier
Which of the following lists of atoms are arranged in order of INCREASING first ionization energy?
Li < O < N < F
Select the spectator ions for the following reaction in aqueous solution, AgNO3 + LiI → AgI + LiNO3
Li+(aq), NO3-(aq)
Which best explains the following boiling points in Kelvin temperature of the noble gas family? He = 4 K Ne = 25 K Ar = 95 K Kr = 125 K Xe = 170 K
London dispersion forces
Which of the following intermolecular forces are ordered correctly from the weakest to the strongest?
London dispersion, dipole-dipole, hydrogen-bonding, and ionic
The molecules in a sample of SOLID SO2 (O=S=O) are attracted to each other by a combination of
London forces and dipole-dipole interactions
Which of the following compounds has the lowest viscosity?
N2(g)
Which TWO of the following combinations of quantum numbers are NOT allowed?
N=6 l=-5 ml=-1 ms=1/2 N=5 l=4 ml=-5 ms=1/2
Which of the following is not a strong base?
NH3
Complete the following reaction in aqueous solution. Fe(NO3)2 + (NH4)2CO3 → What are the spectator ions?
NH4+(aq), NO3-(aq)
In which of the following does nitrogen have an oxidation state of +4?
NO2
The correct order of increasing ionization energy from left to right in the following elements is: Li, Na, C, O, F.
Na < Li < C < O < F
The correct formula of the products in the balanced neutralization reaction between sodium hydroxide and sulfuric acid are _________________________ (Hint: write the full balanced equation first)
Na2SO4 + 2H2O
Aqueous solutions of potassium sulfate (K2SO4) and ammonium nitrate (NH4NO3) are mixed together. Which statement is correct?
No reaction will occur
Five measurements were made by a student of the height of a building, the values recorded were 512.5m, 513.0m, 511.9m, 512.3m, and 512.8m. If the provided exact value of the height was 500.0m, was this measurement accurate?
No, the values are farther from the actual value provided
An element has the electron configuration [Kr] 5s2 4d10 5p5. The element is a(n)
Nonmetal
Atoms having equal or nearly equal electronegativities are expected to form
Nonpolar covalent bond
If equal masses (in grams) of hydrogen gas and oxygen gas are reacted to form water, which substance will be limiting? (Hint: write the balanced equation first).
Oxygen gas is limiting
The numbers of protons, neutrons, and electrons, respectively, in 3215P3- are:
P=15, N=17,E=18
Which unit takes into account the relative ability of radiation to cause damage?
REM
What is the charge of Cr in the formula Cr2O3?
+3
What is the possible charge of the underlined atoms in the following compounds from left to right, respectively? AlBr3 ZnBr2 NaCl CaO
+3, +2, +1, +2
The oxidation state of chlorine in ClO3- is:
+5
Calculate the work for the expansion of CO2 from 1.0 to 2.2 liters against a pressure of 1.0 atm at constant temperature.
-1.2 L·atm
At 25°C, the following heats of reactions are given: 2ClF + O2 → Cl2O + F2O ΔH = 167.4 kJ/mol 2ClF3 + 2O2 → Cl2O + 3F2O ΔH = 341.4 kJ/mol 2F2 + O2 → 2F2O ΔH = -43.4 kJ/mol At the same temperature, calculate ΔH for the reaction: ClF + F2 → ClF3
-108.7 kJ/mol
A gas absorbs 0.0 J of heat and then performs 15.8 J of work. The change in internal energy of the gas is
-15.8 J
Using the information below, calculate ΔHf° for PbO(s) PbO(s) + CO(g) → Pb(s) + CO2(g) ΔH° = -131.4 kJ ΔHf° for CO2(g) = -393.5 kJ/mol ΔHf° for CO(g) = -110.5 kJ/mol
-151.6 kJ/mol
Calculate ΔH° for the reaction C4H4(g) + 2H2(g) → C4H8(g), using the following data: ΔH°combustion for C4H4(g) = -2341 kJ/mol ΔH°combustion for H2(g) = -286 kJ/mol ΔH°combustion for C4H8(g) = -2755 kJ/mol
-158 kJ
Consider the following processes: 3B → 2C + D ΔH = -125 kJ/mol. (1/2)A → B ΔH = +150 kJ/mol E + A → D ΔH = +350 kJ/mol Calculate ΔH for: B → E + 2C
-175 kJ/mol
For the complete combustion of 1.000 mole of propane (C3H8) gas at 298 K and 1 atm pressure, ΔH° = -2220 kJ/mol. What will be the heat when 4.70 g of propane is combusted under these conditions?
-237 kJ
The heat of formation of Fe2O3(s) is -826.0 kJ/mol. Calculate the heat of the reaction 4Fe(s) + 3O2(g) 2Fe2O3(s) when a 43.20-g sample of iron is reacted.
-319.5 kJ
Calculate the change in energy in kJ/mol for the transmutation of radium from the given molar masses: Ra → He + Rn Ra = 226.0254 g/mol He = 4.0026 g/mol Rn = 222.0176 g/mol
-4.7 × 108 kJ/mol
Calculate the work associated with the expansion of a gas from 42.0 L to 79.0 L at a constant pressure of 14.0 atm.
-518 L·atm
For the reaction: AgI(s) + 1/2 Br2(g) → AgBr(s) + 1/2 I2(s), ΔH° = -54.0 kJ ΔHf° for AgBr(s) = -100.4 kJ/mol ΔHf° for Br2(g) = +30.9 kJ/mol The value of ΔHf° for AgI(s) is:
-61.8 kJ/mol
18.4oF converted to oC becomes
-7.44 C
A gas delivers 874 J of heat and then has 159 J of work done upon it. The change in internal energy of the gas is
-715 J
In Rutherford's alpha particle scattering experiment, the alpha particles beamed at thin gold foil may (select 2 matching answers)
-pass directly through the foil without changing direction -be reflected by direct contact with the nuclei of atoms
Calculate the bond order of the molecule Ne2 after filling the required number of electrons in the configuration scheme order given below: (σ1s) (σ*1s) (σ2s) (σ*2s) (σ2p) (π2p) (π*2p) (σ*2p)
0
How many electrons will be available in the given set of quantum numbers: n = 2, l = 2, ml = 2
0
How many f orbitals have the value n = 3?
0
In the cyanide ion (CN-), the nitrogen has a formal charge of (Draw the Lewis structure and calculate the formal charge)
0
The electron configuration of a particular diatomic species is (σ2s)2(σ*2s)2(σ2p)2(π2p)2(π*2p)4. What is the bond order for this species?
0
The nuclideN is unstable. What type of radioactive decay would be expected?
0 1 e
A 7.11-g sample of potassium chlorate was decomposed according to the following equation: 2KClO3 → 2KCl + 3O2 How many moles of oxygen are formed?
0.0870 mol
NaHCO3 is the active ingredient in baking soda. How many grams of oxygen are in 0.30 g of NaHCO3?
0.17 g
240 grams in kilograms will be
0.240 kg
A balloon contains an anesthetic mixture of cyclopropane (cp) and oxygen (O2) at 202 torr and 570. torr, respectively. What is the ratio of the number of moles of cyclopropane to moles of oxygen? =
0.354
What will be the resulting molarity of a 250 mL solution which was made from the original 20 mL of 4.5 M of NaOH solution?
0.36 M
Exactly 312.4 J heat will raise the temperature of 10.0 g of a metal from 25.0°C to 60.0°C. What is the specific heat capacity of the metal?
0.893 J/g°C
The local weather forecaster reports that the current barometric pressure is 29.4 inches of Hg. What is the current pressure in atm.? (Use the necessary conversion factors)
0.983 atm
Atoms that are sp2 hybridized form ____ pi bond(s).
1
The number of unpaired electrons in the outer subshell of a Cl atom is
1
Which of the following electron configurations for the species in their ground state are correct? I. Ca: 1s2 2s2 2p6 3s2 3p6 4s2 II. Mg: 1s2 2s2 2p6 3s1 III. V: [Ar]3s2 3d3 IV. As: [Ar]4s2 3d10 4p3 V. P: 1s2 2s2 2p6 3p5
1 and 4
Consider a sample of helium gas in a cylinder fitted with a piston. The piston is frictionless but has a mass of 10.0 kg applying inward. Which of the following processes will cause the piston to move outward? Assume ideal behavior. I. heating the helium II. removing some of the helium from the cylinder III. turning the cylinder upside down IV. increasing the pressure outside the cylinder
1 only
A sample of oxygen gas has a volume of 5.82 L at 27°C and 800.0 torr. How many oxygen molecules does it contain? (Use R = 62.3637 L Torr mol-1 K-1)
1.5 × 1023
Match the type of measurement to the unit given below. (The numbers on the left column are for reference only, just focus on the units).
10 mm .......................length 2.5 milliliter.............volume 125 K............................temperature 1 milligram................mass 5.0 g/L........................density
Gaseous chlorine is held in two separate containers at identical temperature and pressure. The volume of container A is 1.30 L, and it contains 6.70 mol of the gas. The volume of container B is 2.02 L. How many moles of the gas are in container B?
10.4 mol
Consider the reaction between Mg(s) and HCl(aq) to produce aqueous magnesium chloride and hydrogen gas. How many liters of hydrogen gas at STP will be produced when 12.15 g of magnesium reacts with an excess of hydrochloric acid? (You need a balanced chemical equation for this)
11.2 L
A physics experiment is conducted at a pressure of 15.1 kPa. What is this pressure in mmHg? (101.325 kPa = 760 mmHg)
113mm Hg
How many protons and electrons does the most stable ion of magnesium (Mg) have? (Hint: change the given atom into its stable ion first)
12 protons, 10 electrons
Nitric oxide, NO, is made from the oxidation of NH3, and the reaction is represented by the equation: 4NH3 + 5O2 → 4NO + 6H2O What mass of NO can be produced from 6.82 g of NH3?
12.0 g NO
Sulfuric acid may be produced by the following process: 4FeS2 + 11O2 → 2Fe2O3 +8SO2 2SO2 + O2 → 2SO3 SO3 + H2O → H2SO4 How many moles of H2SO4 will be produced from 6.15 moles of FeS2?
12.3 g feedback: Step 1: Start with 6.15 moles FeS2 Step 2: 4 moles FeS2 is 8 moles SO2 Step 3: 2 moles SO2 is 2 moles SO3 Step 4: 1 mole SO3 is 1 mol H2SO4 Step 5: multiply and divide the necessary numbers to get the answer in mol H2SO4.
The bond angles about the carbon atom in the formaldehyde molecule, H2C=O, are about:
120
The mass of 1.12 liters of gas Y at STP is found to be 6.23 g. The molar mass of gas Y is
125 g/mol
How many atoms (total) are there in one formula unit of Ca3(PO4)2?
13
What is the mass of a rock which is 5.0 cm3 in volume and has density 2.6 g/cm
13g
What volume is occupied by 17.8 g of methane (CH4) at 27°C and 1.95 atm? Use R = 0.082 L atm mol-1 K-1
14.0 L
A sample of an unknown gas takes 434 s to diffuse through a porous plug at a given temperature. At the same temperature, N2(g) takes 175 s to diffuse through the same plug. What is the molar mass of the unknown gas?
172 g/mol
How many oxygen atoms are there in 3 formula units of Al(NO2)3?
18
Consider the following reaction: CH4(g) + 4Cl2(g) CCl4(g) + 4HCl(g) What mass of CCl4 is formed by the reaction of 1.93 g of methane with an excess of chlorine?
18.5 g
Using the following thermochemical data: 2Y(s) + 6HF(g) → 2YF3(s) + 3H2(g) ΔH° = -1811.0 kJ/mol 2Y(s) + 6HCl(g) → 2YCl3(s) + 3H2(g) ΔH° = -1446.2 kJ/mol Calculate ΔH° for the following reaction: YF3(s) + 3HCl(g) → YCl3(s) + 3HF(g)
182.4 kJ/mol
Which of the following electron distributions among the molecular orbitals of nitrogen monoxide (NO) molecule, from left to right in order is correct? σ1s, σ1s*, σ2s, σ2s*, π2py=π2px, σ2pz, π2py*=π2px*, σ2pz*
2 2 2 2 4 2 1 0
Consider the reaction: C2H5OH(l) + 3O2(g) → 2CO2(g) + 3H2O(l); ΔH = -1.37 × 103 kJ Consider the following propositions: I. The reaction is endothermic. II. The reaction is exothermic. III. The enthalpy term would be different if the water formed was gaseous. Which of these propositions is (are) true?
2 and 3
When comparing Be2 and H2: Which of the following statements is/are true? I. Be2 is more stable because it contains both bonding and antibonding valence electrons. II. H2 has a higher bond order than Be2. III. H2 is more stable because it only contains σ1s electrons. IV. H2 is more stable because it is diamagnetic, whereas Be2 is paramagnetic.
2 and 3
A paramagnetic substance has unpaired electrons and a substance with no unpaired electrons is a diamagnetic substance. Using these definitions, which of the following statements, I-IV, is/are true about the element, Hg? I. Hg is paramagnetic. II. f orbitals are filled in the electron configuration of Hg. III. A Hg atom has 5 unpaired electrons. IV. The electron configuration of Hg is [Xe] 6s24f145d10.
2 and 4
Which of the following are oxidation-reduction reactions? I) NaOH + HCl → NaCl + H2O II) Cu + 2AgNO3 → 2Ag + Cu(NO3)2 III) Mg(OH)2 → MgO + H2O IV) N2 + 3H2 → 2NH3
2 and 4 Feedback: One with the single element present are the oxidation-reduction (redox) processes, does not matter which side and how many, just one will be enough.
Phosphoric acid, H3PO4, is a triprotic acid. What is the total number of moles of H+ available for reaction in 1.50 L of 0.500 M H3PO4?
2.25 moles feedback: n = Liters × Molarity = 1.50 L × 0.500 M, this gives the number of moles of H3PO4 Now 1 mole H3PO4 has 3 moles H+. So, multiply the number of moles you got above by 3 to get 2.25 moles.
How many grams of NaCl are contained in 350. mL of a 0.115 M solution of sodium chloride?
2.35g feedback: n = Liters × Molarity = 0.350 L × 0.115 M Find the grams of NaCl by multiplying the moles by its molar mass. You will get 2.35 g NaCl
Which one of the following statements is true?
200 ml is the same as 200 cm3
Calculate ΔH°rxn for this reaction. NaNO3(s) + H2SO4(l) => NaHSO4(s) + HNO3(g) from the given values of ΔH°f[NaNO3(s)] = -467.8 kJ/mol; ΔH°f[NaHSO4(s)] = -1125.5 kJ/mol; ΔH°f[H2SO4(l)] = -814.0 kJ/mol; ΔH°f[HNO3(g)] = -135.1 kJ/mol.
21.2 kJ
A chunk of lead at 91.7°C was added to 200.0 g of water at 15.5°C. The specific heat of lead is 0.129 J/g°C, and the specific heat of water is 4.18 J/g°C. When the temperature stabilized, the temperature of the mixture was 19.4°C. Assuming no heat was lost to the surroundings, what was the mass of lead added?
350 g
The Cs-131 nuclide has a half-life of 30. years. After 107 years, about 3.0 grams remain. The original mass of the Cs-131 sample is closest to
36g
If 34.0 g of O2 are mixed with 34.0 g of H2 and the mixture is ignited, what mass of water is produced?
38.3 g
The net ionic equation for the reaction of calcium bromide and sodium phosphate contains which of the following species? The balanced complete equation is given for your reference: 3CaBr2 (aq) + 2Na3PO4 (aq) Ca3(PO4)2 (s) + 6NaBr (aq) The number of the species also has to be correct, not only the type.
3Ca2+ has to be present in the net equation from the balanced equation given.
An atom of fluorine contains nine electrons. How many of these electrons are in s orbitals?
4
How many significant figures are there in the notation: 0.06102?
4
Consider the following molecules. I. BF3 II. CHBr3 (C is the central atom) III. Br2 IV. XeCl2 V. CO VI. SF4 Select the molecule(s) that fit this statement: These molecules have a trigonal bipyramidal electron pair arrangement.
4 and 6
A 72.5-g sample of SrCl2 is dissolved in 112.5 mL of solution. Calculate the molarity of this solution.
4.07 m
Calculate the energy of a photon of blue light that has a wavelength of 475 nm?
4.18 × 10-19 J
Calculate the percentage error on a calculation that had an average of 45.23 m but the actual value was 47.23 m.
4.235%
The measurement 0.000 004 3 m, expressed correctly using scientific notation, is
4.3 × 10-6 m
What mass of NaOH is required to react completely with 25.0 mL of 2.2 M H2SO4?
4.4 g
For the reaction P4O10(s) + 6H2O(l) → 4H3PO4(aq), what mass of P4O10 must be consumed if 1.68× 1023 molecules of H2O are also consumed?
4.75 × 10 2 g P4O10
Consider the following reaction: CH4(g) + 4Cl2(g) CCl4(g) + 4HCl(g) What mass of CCl4 will be formed if 1.20 moles of methane react with 1.07 moles of chlorine? (Hint: this is a limiting reagent problem)
41.1 g
CH4(g) + 4Cl2(g) → CCl4(g) + 4HCl(g), ΔH = -434 kJ Based on the above reaction, what energy change occurs when 1.2 moles of methane (CH4) reacts?
5.2 × 105 J are released
How many atoms of hydrogen are present in 7.85 g of water?
5.25 × 1023
Calculate the mass of 5 atom(s) of copper in grams.
5.28 × 10-22 g
A 9.56-g piece of solid CO2 (dry ice) is allowed to sublime in a balloon. The final volume of the balloon is 1.00 L at 302 K. What is the pressure of the gas?
5.38 atm
A sample of 35.1 g of methane gas has a volume of 4.24 L at a pressure of 2.70 atm. Calculate the temperature.
63.8 K
What is the wavelength of a photon of red light (in nm) whose frequency is 4.55 × 1014 Hz?
659 nm
All halogens have which of the following number of valence electrons?
7
The valve between a 5-L tank containing a gas at 9 atm and a 10-L tank containing a gas at 6 atm is opened. Calculate the final pressure in the tanks.
7 atm
What will be the pressure of a sample of 48.0 grams of oxygen gas in a glass container of volume 5.2 L at 25 °C? Use R = 0.082 L atm mol-1 K-1
7.05 atm
An oxide of iron has the formula Fe3O4. What mass percent of iron does it contain?
72%
What mass of calcium chloride, CaCl2, is needed to prepare 4.600 L of a 1.53 M solution?
781 g
If four atomic orbitals on one atom overlap four atomic orbitals on a second atom, how many molecular orbitals will form?
8
Consider the reaction: C2H5OH(l) + 3O2(g) → 2CO2(g) + 3H2O(l); ΔH = -1.37 × 103 kJ When a 27.8-g sample of ethyl alcohol (molar mass = 46.07 g/mol) is burned, how much energy is released as heat?
8.27 × 102 kJ Feedback Divide 27.8 g by 46.07 to get the number of moles of ethyl alcohol. Multiply the heat given by the number of moles to get the energy released.
A 5.95-g sample of AgNO3 is reacted with BaCl2 according to the equation 2AgNO3(aq) + BaCl2(aq) Ba(NO3)2(aq) + 2AgCl(s) to give 4.07 g of AgCl. What is the percent yield of AgCl?
81.1%
The half-life ofis 28.1 years. How long will it take a 10.0-g sample ofto decompose to 1.25 g?
84
A gas absorbs 606 J of heat and then has 273 J of work done upon it. The change in internal energy of the gas is
879 J
Calculate the average value for the following temperatures of different times of the day a student measured: 82.4, 85.7, 87.6, 91.5, 93.4, and 97.5 degrees F. Use the correct significant figures.
89.7 oF
A radioactive element has a half-life of 2.3 hours. How many hours will it take for the number of atoms present to decay to one-sixteenth of the initial value?
9.2
You need to make a 200 ml of 0.9M HCl solution from a stock solution which is 2.0 M. What volume of the stock solution should you take?
90ml
Calculate the work associated with the compression of a gas from 121.0 L to 80.0 L at a constant pressure of 23.4 atm.
959 L atm
Given a cylinder of fixed volume filled with 1 mol of argon gas, which of the following is correct? (Assume all gases obey the ideal gas law.)
A cylinder of identical volume if filled with 1 mole He instead of Ar would contain the same number of atoms.
Which of the following statements is true concerning ideal gases?
A gas exerts pressure as a result of the collisions of the gas molecules with the walls of the container.
Given the equation 3A + B → C + D, you react 2 moles of A with 1 mole of B. Which of the following is true?
A is the limiting reactant because you need 3 moles of A and have 2.
Which one of the following statements about atomic structure is false?
A.) The number of protons and neutrons is always the same in the neutral atom B.) An atom is mostly empty space. C.) Almost all of the mass of the atom is concentrated in the nucleus. D.) The protons and neutrons in the nucleus are very tightly packed THE CORRECT ANSWER IS A
All of the following statements are true by themselves. Which one of these follows the Law of Multiple Proportions?
A.) The percentage of Ca by mass in the compound CaS is the same for all pure samples of CaS obtained from any source. B.) The atomic masses of all of the elements in the periodic table have fixed values. C.) All samples of chlorine contain 35Cl and 37Cl in the same (definite) ratio. D.) The mass of oxygen that is combined with a fixed mass of nitrogen in each of the binary nitrogen oxides can be expressed as a ratio of small whole numbers. THE CORRECT ANSWER IS D
Which of the following statements (A-D) is false?
A.) The process of splitting a heavy nucleus into two nuclei with smaller mass numbers is called fission. B.) All of the above statements are true. C.) Archaeologists use radioactivity to determine the age of some artifacts and rocks. D.) Nitrogen can be changed into oxygen by bombarding it with alpha particles. E.) A beta particle is a particle with the same mass as the electron but opposite charge The correct answer is E
In writing the complete ionic equation for the reaction (if any) that occurs after aqueous solutions of KOH and Mg(NO3)2 are mixed, which of the following compounds would not be written as (broken down to) ionic species?
Mg(OH)2
Which pair of ions would not be expected to form a precipitate when dilute solutions of each are mixed?
Mg2+, SO42-
Which of the following is a correctly balanced equation
MnO2 + 4HCl → Cl2 + 2H2O + MnCl2
The MnO4- is often used to analyze for the Fe2+ content of an aqueous solution via the reaction MnO4-(aq) + Fe2+(aq) + H+(aq) → Fe3+(aq) + Mn2+(aq) + H2O(l)
MnO4-(aq)
By constructing their Lewis structures, decide which of the following species could probably not exist as a true stable molecule.
N2H6
According to the first law of thermodynamics, the energy of the universe is constant. Does this mean that ΔE is always equal to zero?
No, ΔE does not always equal zero because it refers to the system's internal energy, which is affected by heat and work.
Which of the following salts is/are expected to be insoluble in water? I) sodium sulfide II) barium nitrate III) ammonium sulfate IV) potassium phosphate
None are insoluble ( all are soluble)
How many protons, neutrons and electrons, respectively in that order, are present in the Se2- anion formed by one atom of 79Se?
P=34, N=45, E=36
The five calculated values are 2.3, 2.3, 2.2, 2.2, and 2.3. Their average value is 2.25. Now, decide which one of the following best describes the given data.
Precise and accurate
Which form of electromagnetic radiation has the longest wavelengths?
Radio waves
A chloride of rhenium contains 63.6% rhenium. Find out by calculation the empirical formula of this compound?
ReCl3
Which of the following properties of a real gas is related to the b coefficient in the van der Waals equation?
Real gases consist of molecules or atoms that have volume
In the reaction N2(g) + 3H2(g) → 2NH3(g), N2 is (Careful with this equation: The hydrogen in NH3 is a +1 hydrogen, not a -1 hydrogen)
Reduced
Which ion pairs i-iv below has the larger ionic radius? Pair i) O2- or S2- Pair ii) Fe2+ or Fe3+ Pair iii) S2- or K+ Pair iv) P3- or N3- The correct answer in order from left to right (pair i to pair iv) is-
S2- Fe3+ S2- P3-
Which ion is larger in each pair? i) O2- or S2- ii) Fe2+ or Fe3+ iii) S2- or K+
S2-, Fe2+, S2-
A compound composed of sulfur and fluorine is found to contain 25.24% by mass of sulfur. If the molar mass of the compound is 254.11 g/mol, what is its molecular formula? (Hint: first find the empirical formula)
S2F10
A gas X has a diffusion rate just 1/2 of the diffusion rate of methane (CH4). Which of the following X could be?
SO2
In the quantum theory, the angular momentum quantum number (l) is most directly associated with which property of orbitals?
Shape Feedback: n refers to energy level and the size of the shell, l refers to the shape of the orbitals, ms refers to the orientation of the orbital, and s refers to the spin of the electron.
The hybridization of the central atom, Al, in AlBr3 is
Sp2
If 5.0 kJ of energy is added to a 15.5-g sample of water at 10.°C, the water is- (Hint: calculate the final temperature, use the sp. heat capacity to be 4.184 J/goC )
Still a liquid
If more than one neutron from each fission event causes another fission event, the fission situation is described as
Supercritical
At the same temperature, lighter molecules will have a higher average root mean square velocity than heavier molecules
TRUE
The freezing point of helium is -270°C. The freezing point of xenon is -112°C. Both of these are in the noble gas family. Which of the following statements is supported by these data?
The London dispersion forces between the helium molecules are less than the London dispersion forces between the xenon molecules.
Which of the following is not a factor in determining the biological effects of radiation exposure?
The age of the organism at which the exposure occurs
In the lab, you mix two solutions (each originally at the same temperature) and the temperature of the resulting solution decreases. Which of the following is true?
The chemical reaction is absorbing energy
Imagine a 10 g chunk of aluminum (density = 2.7 g/cm3) and a 10 g chunk of iron (density = 7.9 g/cm3). Which of the following is true?
The chunk of iron is smaller than the chunk of aluminum.
When a nonpolar liquid displays a convex meniscus, which of the following explains this behavior?
The cohesive forces are stronger than the adhesive forces to the glass.
You have a sample of zinc (Zn) and a sample of aluminum (Al). You have an equal number of atoms in each sample. Which of the following statements concerning the masses of the samples is true?
The mass of the zinc sample is more than twice as great as the mass of the aluminum sample
Two metals of equal mass with different heat capacities are subjected to the same amount of heat. Which undergoes the smallest change in temperature?
The metal with the higher heat capacity.
The limiting reactant in a reaction
The one that finishes first, the one that is limited in amount, the one that has the lower moles than needed by the equation. All of this describes the limiting reactant.
You have 0.4 g of helium gas (He) in a rigid steel container. You add exactly 0.4 g of neon gas (Ne) to this container. Which of the following best describes what happens? Assume that the temperature is constant.
The pressure in the container increases but does not exactly double.
Dalton's law of partial pressures states that:
The total pressure of a mixture of gases is the sum of the partial pressure of all of the gaseous compounds.
Charles's law states that:
The volume of a fixed amount of gas is directly proportional to its temperature in Kelvin at constant pressure.
Boyle's law states that:
The volume of a fixed amount of gas is inversely proportional to its pressure at constant temperature.
Which metals form cations with varying positive charges?
Transition metals
A 100 g piece of pure iron has the same density as a 50 g piece of pure iron.
True
If the particles of a mixture settle down at the bottom after certain time, this mixture must be a heterogeneous mixture
True
Larger bond order means greater bond strength
True
Pb(OH)2 is a weak electrolyte compound
True
The mass of 1000 cm3 of water (density 1g/cm3) is 1 kg.
True
The mixture of salt, sugar, water, and apple juice after mixing for 2 minutes becomes a homogeneous mixture
True
The mixtures are always considered impure substances.
True
The number 650 000 has two significant figures.
True
The reactant which, when used up completely, can produce the least amount of product, is the limiting reactant.
True
The specific heat capacities of metals are relatively low.
True
The undissolved solid formed when two clear chemicals react is called a 'precipitate'.
True
When electron configurations differ from expected, it is because orbitals rather want to be half-filled to be stable than to be unfilled.
True
Whenever a set of equivalent tetrahedral atomic orbitals is required, an atom will adopt a set of sp3 orbitals.
True
neutral element's all atoms have the same number of electrons.
True
Titanium (Ti) has __________ in its d orbitals.
Two electrons
The greatest radiation exposure for Americans comes from which of the following?
a combination of the natural causes of radiation including cosmic rays
The most likely decay mode (or modes) of the unstable nuclide 11 6C would be:
either positron production or electron capture, or both
The elements of group 15, the nitrogen family, form compounds with hydrogen having the boiling points listed below: SbH3 -17°C, AsH3 -55°C, PH3 -87°C, NH3 -33°C The first three compounds illustrate a trend where the boiling point decreases as the mass decreases; however, ammonia (NH3) does not follow the trend because of
hydrogen bonding
A tentative scientific explanation which may or may not be rejected upon further experimentation is called a
hypothesis
A tentative thought- or experiment-derived explanation is known as a(an)
hypothesis
As the bond order of a bond increases, the bond energy ______ and the bond length ______.
increases, decreases
The bonds between hydrogen and oxygen within a water molecule can be characterized as __________.
intramolecular forces
The correct name for LiCl is
lithium chloride
The cubic centimeter (cm3 or cc) has the same volume as a
milliliter
What is the correct name (IUPAC) of the following non-metal compounds, in order from left to right? NO, P2O5, N2O3, ClO2
nitrogen monoxide, diphosphorus pentoxide, dinitrogen trioxide, chlorine dioxide
ALL of the following reactions 2Al(s) + 3Br2(l) → 2AlBr3(s) 2Ag2O(s) → 4Ag(s) + O2(g) CH4(l) + 2O2(g) → CO2(g) + 2H2O(g)
oxidation-reduction reactions
A species has the following MO configuration: (σ1s)2(σ1s*)2(σ2s)2(σ2s*)2(σ2p)2(π2p)2 This substance is
paramagnetic with two unpaired electrons
In the reaction P4(s) + 10Cl2(g) → 4PCl5(s), choose TWO statements that are true.
phosphorus is oxidized AND chlorine is an oxidizing agent
A statement describing a relationship that is observed in nature to occur consistently time after time is a(an)
scientific law.
A scheme of thought that has been proved by several experiments by several people at different places for long periods of time is a(an)
scientific theory
A π (pi) bond is the result of the
sidewise overlap of two parallel p orbitals
According to the postulates of the kinetic theory of gases, the average speed of the molecules of a given gas is proportional to the
square root of the absolute temperature
What is responsible for capillary action, a property of liquids in which the liquid climbs up a narrow tube?
surface tension and adhesive forces
The following reactions 2K(s) + Br2(l) → 2KBr(s) -AgNO3(aq) + NaCl(aq) → AgCl(s) + NaNO3(aq) -HCl(aq) + KOH(aq) → H2O(l) + KCl(aq)
the first one is a redox reaction, the second one is a precipitate reaction, the third is an acid-base reaction
For a measurement to be precise
the measurement should give consistently similar values even if not close to the actual value
Which is NOT the correct equation for the relationship among density, mass, and volume?
volume = density / mass
Five measurements were made by a student of the height of a building, the values recorded were 512.5m, 513.0m, 511.9m, 512.3m, and 512.8m. The actual value was 500.0 m. Was this measurement precise?
yes, the values are close to each other
Consider the following numbered processes: 1. A → 2B (heat of reaction: H1) 2. B → C + D (heat of reaction: H2) 3. E → 2D (heat of reaction: H3) ΔH for the process A → 2C + E is
ΔH1 + 2ΔH2 - ΔH3
In which of the partially charged molecules below, which is the bond polarity incorrectly represented?
δ+Mg---Hδ- δ+H---Fδ- δ+Si---Sδ- δ+K---Oδ- δ+Cl--Iδ-
Nitrogen has five valence electrons. Consider the following electron arrangements. 2s 2p Which represents the ground state for N?
↑↓ ↑ ↑ ↑
In the gaseous phase, which of the following diatomic molecules would be the most polar?
CsF
The oxidation state of iodine in I2O3 is:
+3
Which of the following atoms has the largest ionization energy?
A.) Ne B.) O C.) Be D.) Li E.)K the correct answer is A
Which of the following substances contains two pi bonds?
C2H2
Which type of radiation has the lowest penetrating ability?
alpha particle
Which of the following are incorrectly paired?
ammonia, NH3 iodine trichloride, ICl3 sulfur hexafluoride, SF6Phosphorus, Pr
All of the following are characteristics of nonmetals except:
appear in the upper left-hand corner of the periodic table
The following reactions ZnBr2(aq) + 2AgNO3(aq) → Zn(NO3)2(aq) + 2AgBr(s) KBr(aq) + AgNO3(aq) → AgBr(s) + KNO3(aq) are examples of
both are precipitate reactions
When electrons in a molecule are not found between a pair of atoms but move throughout the molecule, this is called
delocalization of electrons
You are given the following boiling point data. Which one of the liquids would you expect to have the highest vapor pressure at room temperature?
diethyl ether, CH3CH2-O-CH2CH3 34.5°C
Which of the following is the major force of attraction between molecules of CCl4?
dispersion forces
Which of the following is the major force of attraction between molecules of CH4?
dispersion forces
Bromine exists naturally as a mixture of bromine-79 and bromine-81 isotopes. An atom of bromine-79 contains
35 protons, 44 neutrons, 35 electrons
The following reaction: 2Ce4+ + 2I- → I2 + 2Ce3+
Ce is reduced and I is oxidized
Which of the gas laws best describes the situation given below: "An inflated balloon shrinks when kept in a container having liquid nitrogen."
Charles's Law
Of the following elements, which is most likely to form an ion with charge -1?
Cl
What is true about this reaction? MnO2 + 4HCl → Cl2 + 2H2O + MnCl2
Cl is oxidized
When solutions of barium chloride and ammonium sulfate react, which of the following is a spectator ion?
Cl-, NH4+
Four identical 1.0-L flasks contain the gases He, Cl2, CH4, and NH3, each at 0°C and 1 atm pressure. Which gas has the highest density?
Cl2
Order the following in increasing rate of effusion: F2, Cl2, NO, NO2, CH4
Cl2 < NO2 < F2 < NO < CH4
1s2 2s2 2p6 3s2 3p6 4s2 3d7 is the correct electron configuration for which of the following atoms?
Co
The formula for cobalt (II) chloride is
CoCl2
What component of a nuclear reactor moderates the rate of the reaction?
Control rods
positron production and electron capture
Critical mass
Aqueous solutions of sodium sulfide and copper(II) chloride are mixed together. Which statement is correct?
CuS will precipitate from solution.
An element E has the electron configuration [Kr] 5s24d105p2. The formula for the fluoride of E is most likelyAn element E has the electron configuration [Kr] 5s24d105p2. The formula for the fluoride of E is most likely
EF4
Which of the following exhibits the correct orders for both atomic radius and ionization energy, respectively? (smallest to largest)
F, O, S, and S, O, F
Bohr's model correctly describes the hydrogen atom and other small atoms.
FALSE
Water sits in an open beaker. Assuming constant temperature and pressure, the rate of evaporation decreases as the water evaporates.
FALSE
2.04 moles of hydrogen gas weighs the same as 2.04 moles of oxygen gas.
False
An acid is a substance that produces OH- ions in water.
False
Glucose, a non-electrolyte, poorly conducts electric charge.
False
Oxidation is the gain of electrons.
False
The number 0.0500 has four significant figures.
False
The property of density is a measure of how heavy an object is.
False
The rounded-off number for the expression 0.3457 to the three significant figures is 0.345.
False
With what volume of 5.00 M HF will 4.03 g of calcium hydroxide react completely, according to the following reaction? 2HF + Ca(OH)2 CaF2 + H2O
21.8 mL Feedback step 1: Start with 4.03 g of calcium hydroxide. Step 2: Convert this gram into moles. Step 3: 1 mol calcium hydroxide is 2 mol HF according to the equation. Step 4: Place 5.00 mol HF on the bottom and 1 L on top. Your final answer will be in liters. which is 0.0218 L = 21.8 mL
At what temperature will 2.50 moles of gas at a pressure of 1.19 atm occupy 50.9 L volume in an expandable container? Use R = 0.082 L atm mol-1 K-1
22.4 C
The heat combustion of acetylene, C2H2(g), at 25°C is -1299 kJ/mol. At this temperature, ΔHf° values for CO2(g) and H2O(l) are -393 and -286 kJ/mol, respectively. Calculate ΔHf° for acetylene. Hint: First write a balanced equation for the combustion i.e. add O2 (g) to get CO2(g) and H2O(l)
227 kJ/mol
Which of the following is a product of α-decay of 238 92U?
234 90 Th
A radioactive isotope of vanadium, 53 23V, decays by producing a β particle and gamma ray. What is the atomic number of the resulting nuclide?
24
Consider the following two compounds:H20 and H2O2. According to the law of multiple proportions, the ratio of hydrogen atoms per gram of oxygen in H2O to hydrogen atoms per gram of oxygen in H2O2 is
2:1
You have two samples of the same gas in the same size container, with the same pressure. The gas in the first container has a Kelvin temperature four times that of the gas in the other container. The ratio of the average velocity of particles in the first container compared to that in the second is
2:1
What is the molar ratio of the components (in order from left to right) when this equation is balanced correctly: Na + H2O NaOH + H2
2:2:2:1
The net ionic equation for the reaction of aluminum sulfate and sodium hydroxide contains which of the following species? (First write the balanced equation, write the complete ionic equation, and cancel the common ions. Not only the type but their number has to be equal)
2Al(OH)3(s)
Which of the following equations is not balanced?
2KClO3 → 2KCl + 3/2 O2
The number of orbitals having a given value of l is equal to
2l + 1
In the Lewis structure for ICl2-, how many lone pairs of electrons are around the central iodine atom?
3
Generally the vapor pressure of a liquid is related to: I. the amount of liquid II. atmospheric pressure III. temperature IV. intermolecular forces
3 AND 4
Which types of processes are likely when the neutron-to-proton ratio in a nucleus is too low? I. α decay II. β decay III. positron production IV. electron capture
3 and 4
A 14.2-g sample of HF is dissolved in water to give 2.0 × 102 mL of solution. The concentration of the solution is:
3.5M
3600025 in correct scientific notation is:
3.600025 x 106
Calculate the number of nitrogen atoms in 240. g of ammonium nitrate.
3.61 x 1024 nitrogen atoms
What is the mass of 9.00 x 1022 atoms of magnesium, Mg?
3.63 g
How many electrons can be contained in all of the orbitals with n = 4?
32
A sample of nitrous oxide, N2O, occupies 16,500 mL at STP. What is the mass of the sample?
32.4 g
When the equation C4H10 + O2 → CO2 + H2O is balanced with the smallest set of integers, the sum of the coefficients is
33
Using the following data, calculate ΔH°rxn for the equation: I2(s) + Cl2(g) → 2ICl (g) ΔH°rxn = ? Cl2(g) → 2Cl(g) ΔH° = 242.3 kJ/mol I2(g) → 2I(g) ΔH° = 151.0 kJ/mol ICl(g) → I(g) + Cl(g) ΔH° = 211.3 kJ/mol I2(s) → I2(g) ΔH° = 62.8 kJ/mol
33.5 kJ/mol
Which of the following statements is FALSE?
A.) A metal-nonmetal reaction involves electron transfer. B.) When a metal reacts with a nonmetal, an ionic compound is formed. C.) When two nonmetals react to make a compound the reaction is an oxidation-reduction reaction. D.)When two nonmetals react, the compound formed is ionic. E.) A metal and a nonmetal reacting together to make a compound will create an oxidation-reduction reaction. The correct answer is D
If the Thomson model of the atom (watermelon model) had been correct, Rutherford would have observed which of the following during his alpha particle scattering experiment?
A.) Alpha particles bouncing off the gold foil. B.) Positive particles formed on the gold foil. C.) Alpha particles going through the gold foil with little or no deflection. D.) Alpha particles greatly deflected by the gold foil. THE CORRECT ANSWER IS C
Which statement is INCORRECT?
A.) An atom of 50Mn has an equal number of electrons and neutrons B.) An atom of 60Zn has an equal number of protons and neutrons C.) An atom of 41K has an equal number of protons and electrons D.) An atom of 18O has an equal number of protons and neutrons E.) An atom of 238U contains 146 neutrons. Correct answer is D
Which of the following statements from Dalton's atomic theory is no longer true, according to modern atomic theory? A
A.) Atoms are not created or destroyed in chemical reactions. B.) Atoms are indivisible in chemical reactions. C.) Elements are made up of tiny particles called atoms. D.) All atoms of a given element are identical THE CORRECT ANSWER IS D
Which of the following statements are true concerning ionic bonding?
A.) Compounds with ionic bonds tend to have low melting points. B.) Ionic bonding occurs between a metal, which has a high affinity for electrons, and a nonmetal, which loses electrons relatively easy. C.) The electronegativity difference between the bonding atoms of ionic compounds is small since the electrons are not shared but rather held together by electrostatic forces. D.) CaCl2 forms because Ca2+ is always a more stable species than the calcium atom alone. E.) All of the given statements are false. THE CORRECT ANSWER IS E
The names given are all correct. One of the formula according to the name given is not correct. Which is that formula?
A.) CuCl, copper(I) chloride B.) NH4Br, ammonium bromide C.) K2CO3, potassium carbonate D.) MnO2, manganese(IV) oxide E.) BaPO4, barium phosphate THE CORRECT ANSWER IS E
Which of the following is paired incorrectly?
A.) HCl - strong acid B.) H2SO4 - strong acid C.) HNO3 - weak acid D.) Ba(OH)2 - strong base E.) Hg(OH)2 - weak base The correct answer is C
Which of the following statements is true?
A.) Ions are formed by adding or removing protons or electrons. B.) Heating water in a beaker with a Bunsen burner results in a 2:1 mixture of hydrogen and oxygen gases. C.) Scientists believe that solids are mostly open space as referenced from Rutherford's gold foil experiment. correct answer is C
Which of the following pairs of compounds can be used to illustrate the law of multiple proportions?
A.) NH4 and NH4Cl B.) NO and NO2 C.) H2O and HCl D.) ZnO2 and ZnCl2 E.) CH4 and CO2 THE CORRECT ANSWER IS C
Which of the following group of elements have the same number of valence electrons?
A.) P, As, Se B.) Na, Ca, Ba C.) P, S, Cl D.) Ag, Cd, Ar E.) none of the given group has the same number of valence electrons. THE CORRECT ANSWER IS E
All of the following are true except:
A.) Positive ions are formed by removing electrons from a neutral atom. B.) Ions are of two types: positive ions and negative ions C.) Protons can be added to an atom's nucleus to make positive ions D.) Metals tend to form positive ions. E.) Negative ions are formed by adding electrons to a neutral atom. THE CORRECT ANSWER IS C
Choose the element with the highest ionization energy. Hide answer choices
A.) S B.) P C.) Al D.) Na E.) Mg the correct answer is A
On the basis of your knowledge of bonding in liquids and solids, which of the following has the lowest melting temperature?
A.) SiO2 B.) Na C.) Cl2 D.) Cu-Zn alloy E.) NaCl THE CORRECT ANSWER IS C
Which of the following statements is incorrect?
A.) The electrons in a polar bond are found nearer to the more electronegative element. B.) Linear molecules cannot have a net dipole moment. C.) Ionic bonding results from the transfer of electrons from one atom to another. D.) Dipole moments result from the unequal distribution of electrons in a molecule. A molecule with very polar bonds can be nonpolar. The correct answer is B
All the following are postulates of the kinetic-molecular theory of gases except:
A.) The gas molecules are in constant motion. B.) The volumes of the molecules are negligible compared with the volume of the container. C.) The collisions between molecules are elastic. D.) The gas molecules are in rapid motion. E.) At a constant temperature, each molecule has the same kinetic energy. The correct answer is E
Which of the following statements is correct?
A.) The internal energy of a system decreases when work is done on the system and heat is flowing into the system. B.) The system does work on the surroundings when an ideal gas expands against a constant external pressure. C.) The internal energy of a system increases when more work is done by the system than heat was flowing into the system. D.) All statements are false. E.) All statements are true THE CORRECT ANSWER IS B
At a given temperature and pressure, a sample of gas A is observed to diffuse twice as fast as a sample of a different gas, B. Based on this:
A.) The molar mass of B is four times that of A B.) The molar mass of B is 1.414 times that of A C.) The molar mass of A is 0.707 times that of B D.) The molar mass of B is one half that of A E.) The molar mass of A is four times that of B The correct answer is A
Which of the following is not a postulate of the kinetic molecular theory?
A.) The moving particles undergo perfectly elastic collisions with the walls of the container. B.) The forces of attraction and repulsion between the particles are insignificant. C.) The average kinetic energy of the particles is directly proportional to the absolute temperature. D.) All of the above are postulates of the kinetic molecular theory. E.) Gas particles have most of their mass concentrated in the nucleus of the atom. The Correct answer is E
Which of the following statements about quantum theory is incorrect?
A.) When filling orbitals of equal energy, two electrons will occupy the same orbital before filling a new orbital. B.) No two electrons can have the same four quantum numbers. C.) Lower energy orbitals are filled with electrons before higher energy orbitals. D.) Two electrons of the same spin cannot be in the same orbital. E.) The energy and position of an electron cannot be determined simultaneously. The correct answer is A
Which of the following reactions does NOT involve oxidation-reduction?
A.) Zn + 2HCl → ZnCl2 + H2 B.) 2Na + 2H2O → 2NaOH + H2 C.) MnO2 + 4HCl → Cl2 + 2H2O + MnCl2 D.) CH4 + 3O2 → 2H2O + CO2 E.) All of the given choices are oxidation-reduction reactions THE CORRECT ANSWER IS E
Which of the following best describes an orbital?
A.) a single space within an atom that contains all electrons of that atom B.) the space in an atom where an electron is most likely to be found C.) small, walled spheres that contain electrons D.) space which may contain electrons, protons, and/or neutrons E.) space where electrons are unlikely to be found in an atom THE CORRECT ANSWER IS B
Which of the following names of compounds is incorrect?
A.) cobalt (II) chloride B.) aluminum (III) oxide C.) diphosphorus pentoxide D.) magnesium oxide THE CORRECT ANSWER IS B
Which of the following elements does not have a Latin name
A.) potassium B.) iron C.) sodium D.)titanium E.) gold correct answer is D
Consider the ionization energy (IE) of the magnesium atom. Which of the following is INCORRECT?
A.)The IE of Mg is lower than that of sodium. B.) The IE of Mg is lower than that of Mg+. C.) The IE of Mg is lower than that of neon. D.) The IE of Mg is higher than that of calcium. E.) The IE of Mg is lower than that of beryllium. the correct answer is A
Which substance can be described as cations bonded together by mobile electrons?
Ag(s)
Aqueous solutions of barium chloride and silver nitrate are mixed to form solid silver chloride and aqueous barium nitrate. The net ionic equation contains which of the following terms?
Ag+(aq)
Consider the reaction between 15.0 mL of a 1.00 M aqueous solution of AgNO3 and 10.0 mL of a 1.00 M aqueous solution of K2CrO4. When these react, a precipitate is observed. What is the formula of the precipitate?
Ag2CrO4
Which element in each pair has the larger atomic radii? Pair i) Al and Si Pair ii) Ar and Br Pair iii) F and I
Al , Br , I
Consider three 1-L flasks at STP. Flask A contains NH3 gas, flask B contains NO2 gas, and flask C contains N2 gas. Which contains the largest number of molecules?
All have the same number of molecules
Rutherford's experiment was important because it showed that:
An atom is mostly empty space
For the elements Ba, F, and P, the order of increasing electronegativity is:
Ba < P < F
Choose the member of each set that best matches the label. Be or Ba Which one is more metallic? N2O(g), MgO(s) Which one is more covalent? O, S, Br Which one has the highest electronegativity?
Ba, N2O, O
Nuclides with too many neutrons to be in the band of stability are most likely to decay by what mode?
Beta emission
Which gas law best describes the situation given below? A packet of chips gets fully inflated when taken to the mountain top from a valley
Boyle's Law
Choose the correct equation for the standard enthalpy of formation of CO(g), where ΔHf° for CO = -110.5 kJ/mol (gr indicates graphite).
C(gr) + 1/2 O2(g) → CO(g), ΔH° = -110.5 kJ
Using the following electronegativity values: C = 2.5 Cl = 3.0 H = 2.1 O = 3.5 Which of the polarity order is correct?
C-H < C-Cl < C-O < H-O
A compound contains 49.32% C, 43.84% O, and 6.85% H by mass. Calculate the empirical formula.
C3H5O2
The empirical formula of a hydrocarbon is CH; its molar mass is 104.1 g/mol. What is the molecular formula of that hydrocarbon?
C8H8
Which of the following ions is most likely to form an insoluble sulfate?
CA2+
Which of the following compounds is expected to have the HIGHEST boiling point?
CH3CH2OH
For which of the following compound does 0.256 mole weigh 12.8 g?
CH3Cl
Which of the following equations correctly describes the combustion of CH4 and O2 to produce water (H2O) and carbon dioxide (CO2)?
CH4 + 2O2 → CO2 + 2H2O
The rate of effusion of an unknown gas was measured and found to be 14.3 mL/min. Under identical conditions, the rate of effusion of pure oxygen (O2) gas is 16.8 mL/min. Based on this information, the identity of the unknown gas could be:
CO2
Which of the following ions is the most unlikely ion to form naturally?
C^4+
You are given a compound with the formula MCl2, in which M is a metal. You are told that the metal ion has 18 electrons. What is the identity of the metal?
Ca
Consider an aqueous solution of calcium nitrate added to an aqueous solution of sodium phosphate. What is the formula of the solid formed in the reaction?
Ca3(PO4)2 (s)
Based on comparative electronegativities from the periodic table, which of the following would you expect to be most ionic?
CaF2
The formula for calcium hydrogen phosphate is
CaHPO4
How many grams of H2O will be formed when 32.0 g H2 is mixed with 84.0 g of O2 and allowed to react to form water?
Feedback Step 1: Write the balanced equation 2H2 + O2 → 2H2O which says 2:1 ratio of H2 to O2 Step 2: Find the mole ratio for the given masses: 32.0/2.016 for H2 and 84.0/32.0 for O2. Obviously, O2 is the limiting reagent here. So you should start with O2 mass, not H2 mass. Step 3: change g O2 into moles i.e. 84.0/32.0 moles Step 4: 1 mol O2 is 2 mol H2O from the equation Step 5: change the mol water to grams water Step 6: multiply and divide the necessary numbers to get the answer.
Consider three 1-L flasks at STP. Flask A contains NH3 gas, flask B contains NO2 gas, and flask C contains N2 gas. In which flask do the molecules have the highest average velocity?
Flask A
For principal quantum number n = 4, how many d orbitals are possible?
For all the principal quantum numbers from 3 and up, the number of d orbitals are 5. n = 1 or 2 do not have any d orbital.
Hydrogen bonds account the for which of the following observation?
For its molar mass, water has a high boiling point.
Consider the following specific heats of metals: Aluminum = 0.897 J/(g°C) Magnesium = 1.02 J/(g°C) Lithium = 3.58 J/(g°C) Silver = 0.237 J/(g°C) Gold = 0.129 J/(g°C) If the same amount of heat is added to 25.0 g of each of these metals, which are all at the same initial temperature, which metal will have the highest temperature?
Gold Feedback: The one with the lowest specific heat has the least heat absorbing capacity raising the temperature highest for that metal.
Consider the compounds CH3OH, CCl4, and CH3Br. For each compound, list the strongest intermolecular force that operates within a sample of that compound.
H-bonding is the strongest intermolecular force in CH3OH, dispersion is the strongest intermolecular force in CCl4, and dipole-dipole is the strongest intermolecular force in CH3Br
Which of the following does not have a standard enthalpy of formation equal to zero at 25°C and 1.0 atm?
H20(l)
For each of the following pairs of substances, select the one expected to have the higher melting point: I. H2O, H2S II. HCl, NaCl III. CH4, C3H8
H2O, NaCl, C3H8
Phosphoric acid can be prepared by reaction of sulfuric acid with "phosphate rock" according to the equation: Ca3(PO4)2 + 3H2SO4 → 3CaSO4 + 2H3PO4 Suppose the reaction is carried out starting with 123 g of Ca3(PO4)2 and 90.2 g of H2SO4. Which substance is the limiting reactant?
H2SO4 Feedback: First, divide each mass by their respective molar masses to find their number of moles. From the equation, for each mole of Ca3(PO4)2 you need 3 moles of H2SO4 Since the moles of H2SO4 are not enough, they are the limiting reagent.
A line in the spectrum of atomic mercury has a wavelength of 256 nm. Calculate the frequency of this wave.
I1.17 × 1015 s-1
Steel is considered to be a(n) __________.
Interstitial Alloy
A 47.4 g sample of a metal is heated to 95.2°C and then placed in a calorimeter containing 120.0 g of water (c = 4.18 J/g°C) at 21.5°C. The final temperature of the water is 24.5°C. Which metal was used?
Iron (c = 0.45 J/g°C)
Which of the following statements best describes the Heisenberg uncertainty principle?
It is impossible to accurately know both the exact location and momentum of a particle
