Name:    CH 221 Practice Exam II

Multiple Choice
Identify the letter of the choice that best completes the statement or answers the question.

1.

The balanced equation for the complete combustion of benzene, C6H6, is
 a. C6H6(l) + 12 H2O → 6 CO2(g) + 15 H2(g) b. C6H6(l) → 6 C(s) + 3 H2(g) c. 2 C6H6(l) + 9 O2(g) → 12 CO (g) + 6 H2O(g) d. C6H6(l) + O2(g) → CO2(g) + H2O(g) e. 2 C6H6(l) + 15 O2(g) → 12 CO2(g) + 6 H2O(g)

2.

Iron reacts with hydrochloric acid to produce iron (II) chloride and hydrogen gas.

Fe(s) + 2 HCl(aq) FeCl2(aq) + H2(g)

How many moles of HCl will react with 3.5 moles of Fe?
 a. 1.0 mol b. 1.8 mol c. 2.0 mol d. 7.0 mol e. 8.5

3.

Copper reacts with nitric acid to produce copper nitrate, nitrogen dioxide gas, and water.

Cu(s) + 4 HNO3(aq) Cu(NO3)2(aq) + 2 NO2(g) + 2 H2O(l)

If you have 0.60 moles of Cu,
 a. you need at least 2.4 moles of HNO3 to produce 1.2 moles of NO2. b. you need at least 0.60 moles of HNO3 to produce 0.60 moles of Cu(NO3)2. c. you need at least 2.4 moles of HNO3 to produce 2.4 moles of NO2. d. you need at least 0.15 moles of HNO3 to produce 0.60 moles of Cu(NO3)2. e. you need at least 0.30 moles of HNO3 to produce 0.60 moles of NO2.

4.

The complete combustion of 2.0 moles of butane gas, C4H10, will
 a. consume 13 mol O2 and produce 8.0 mol H2O. b. consume 5.0 mol O2 and produce 13 mol CO2. c. consume 7.0 mol O2 and produce 8.0 mol CO2. d. produce 8 mol CO2 and 5.0 mol H2O. e. consume 13 mol O2 and produce 8.0 mol CO2.

5.

How many moles of Fe2O3(s) is produced from the reaction of 0.34 mol Fe(s) with 0.30 mol O2(g)?
 a. 0.17 mol b. 0.20 mol c. 0.34 mol d. 0.51 mol e. 0.68 mol

6.

Aspirin is produced by the reaction of salicylic acid (molar mass = 138.1 g/mol) and acetic anhydride (molar mass = 102.1 g/mol).

C7H6O3(s) + C4H6O3(l) C9H8O4(s) + C2H4O2(l)

If you mix 10.0 grams of each reactant, how many grams of aspirin (molar mass = 180.2 g/mol) can theoretically by obtained?
 a. 7.30 g b. 7.66 g c. 9.32 g d. 12.7 g e. 13.0 g

7.

Nitroglycerine decomposes violently according to the unbalanced chemical equation below. How many total moles of gases are produced from the decomposition of 1.00 mol C3H5(NO3)3?

C3H5(NO3)3(l) CO2(g) + N2(g) + H2O(g) + O2(g)
 a. 4.00 mol b. 7.25 mol c. 16.5 mol d. 26.0 mol e. 29.0 mol

8.

Aspirin is produced by the reaction of salicylic acid (molar mass = 138.1 g/mol) and acetic anhydride (molar mass = 102.1 g/mol).

C7H6O3(s) + C4H6O3(l) C9H8O4(s) + C2H4O2(l)

If 1.02 g of C9H8O4 (molar mass = 180.2 g/mol) is produced from the reaction of 3.00 g C7H6O3 and 5.40 g C4H6O3, what is the percent yield?
 a. 7.11% b. 11.6% c. 15.9% d. 26.1% e. 43.1%

9.

Which one of the following compounds is a weak electrolyte when dissolved in water?
 a. CH3CO2H b. NaCH3CO2 c. KNO3 d. Na2SO4 e. sugar

10.

Which of the following compounds are likely to be soluble in water: Ni(OH)2, ZnCl2, CuS, Fe2(CO3)3, AgCl, and Pb(NO3)2?
 a. ZnCl2 b. ZnCl2 and Pb(NO3)2 c. CuS and AgCl d. Fe2(CO3)3 and Ni(OH)2 e. none of the compounds are soluble

11.

A precipitate will form when an aqueous solution of iron(III) chloride is added to ________.
 a. Ca(NO3)2 b. NaOH c. HCl d. NaCH3CO2 e. KClO4

12.

What is the net ionic equation for the reaction of calcium carbonate with a strong acid?
 a. Ca(s) + 2 H+(aq) → Ca2+(aq) + H2(g) b. CaO(s) + 2 H+(aq) → Ca2+(aq) + H2O(l) c. CaCO3(s) + 2 HCl(aq) → CaCl2(aq) + H2CO3(aq) d. CaCO3(s) + 2 H+(aq) → Ca2+(aq) + H2CO3(s) e. CaCO3(s) + 2 H+(aq) → Ca2+(aq) + CO2(g) + H2O(l)

13.

Sulfuric acid is the product of the reaction of ________ and H2O.
 a. SO2 b. SO3 c. SO32- d. SO4- e. SO42-

14.

A major use of calcium oxide (lime. is in pollution control at coal burning power plants. Which reaction below occurs in the smokestack of a power plant?
 a. CaO(s) + SO3(g) → CaSO4(s) b. CaO(s) + SO3(g) → Ca(s) + SO2(g) + O2(g) c. CaO(s) + SO2(g) → CaS(s) + O2(g) d. 2 CaO(s) + C(s) → Ca2C(s) + O2(g) e. CaO(s) + C(s) → CaCO(s)

15.

Which compound is the reducing agent in the reaction below?

I-(aq) + ClO-(aq) IO-(aq) + Cl-(aq)
 a. I- b. ClO- c. H2O d. IO- e. Cl-

16.

Classify the reaction below.

FeCl3(aq) + 3 NaOH(aq) Fe(OH)3(s) + 3 NaCl(aq)
 a. gas forming b. oxidation-reduction c. acid-base d. precipitation e. decomposition

17.

What is the mass, in grams, of solute in 0.175 L of 3.17 × 10-2 M KCl?
 a. 0.00555 g b. 0.181 g c. 0.255 g d. 0.414 g e. 13.5 g

18.

The pH of 6.0 M KOH is 14.78. What is the hydrogen ion concentration of this solution?
 a. 1.7 × 10-15 M b. 2.2 × 10-14 M c. 6.0 × 10-14 M d. 1.0 × 10-6 M e. 1.3 × 10-1 M

19.

Specific heat capacity is
 a. the quantity of heat required to melt 1.00 g of a substance. b. the mass of a substance 1.00 J of energy will heat by 1.00 K. c. the mass of a substance 1.00 cal of energy will heat by 1.00 K. d. the temperature change undergone when 1.00 g of a substance absorbs 1.00 cal. e. the quantity of heat needed to change 1.00 g of a substance by 1.00 K.

20.

Heat capacity is defined as
 a. the amount of heat required to raise the temperature of a substance by 1 K. b. the amount of heat required to raise the temperature of 1 gram of substance by 1 K. c. 4.18 J/g·K. d. 4.18 J/K. e. 4.18 cal/g·K.

21.

Calculate ΔE of a gas for a process in which the gas evolves 27 J of heat and does 24 J of work on the surroundings (i.e. the gas expands)?
 a. -51 J b. -3 J c. +3 J d. 24 J e. +51 J

22.

Commercial cold packs consist of solid ammonium nitrate and water. NH4NO3 absorbs 330. J of heat per gram dissolved in water. In a coffee-cup calorimeter, 3.00 g NH4NO3 is dissolved in 100.0 g of water at 24.0ºC. What is the final temperature of the solution? Assume that the solution (whose total mass is 103.0 g) has a specific heat capacity of 4.18 J/g·K.
 a. 11.0 °C b. 15.9 °C c. 19.1 °C d. 21.6 °C e. 35.9 °C

23.

Determine the heat of vaporization of titanium(IV) chloride given the enthalpies of reaction below.

 Ti(s) + 2 Cl2(g) → TiCl4(l) ΔH = -804.2 kJ Ti(s) + 2 Cl2(g) → TiCl 4(g) ΔH = -763.2 kJ
 a. -1567.4 kJ b. 0.949 kJ c. 41.0 kJ d. 61.3 kJ e. 1567.4 kJ

24.

The standard enthalpy change for the combustion of propane is -2219.9 kJ.

C3H8(g) + 5 O2(g) 3 CO2(g) + 4 H2O(l)

Calculate the standard molar enthalpy of formation for propane based on the following standard enthalpies of formation.

 molecule ΔHfº (kJ) CO2(g) -393.5 H2O(l) -285.8
 a. -103.8 kJ b. -102.8 kJ c. -74.8 kJ d. +52.1 kJ e. +1540.6 kJ

25.

The standard enthalpy of formation of CO2(g) is -393.5 kJ. What is the enthalpy change if 4.49 g C(s) reacts with 9.21 g O2(g) to form CO2(g)?
 a. -113 kJ b. -92.8 kJ c. -87.6 kJ d. -42.7 kJ e. -27.8 kJ

Completion
Complete each sentence or statement.

26.

The percent yield of a chemical reaction is calculated by dividing the actual yield by the __________.

27.

A ________ agent loses electrons in an oxidation-reduction reaction.

28.

________ acid is produced in a larger quantity than any other chemical in the United States. This chemical is used in the production of fertilizers, pigments, alcohol, paper and detergents.

29.

The net ionic equation for the reaction of silver nitrate and sodium chloride is as follows.

Ag+(aq) + Cl-(aq) AgCl(s)

Sodium and nitrate ions are referred to as ________ ions because they are not involved in the reaction.

Essay

30.

Give the name of an acidic oxide and write a balanced chemical equation for the reaction of the oxide with water.

31.

The pH of a sodium hydroxide solution gradually decreases if the solution is left in contact with air. In fact, the process can be hastened if a person exhales over a sodium hydroxide solution. Write a balanced chemical equation that describes the process by which the sodium hydroxide concentration decreases.

32.

You can remove a piece of aluminum foil from a hot oven without using an oven mitt to protect your hand. Why do you not get burned?

33.

What is one advantage and one disadvantage of using hydrogen gas as fuel?