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General, Organic & Biological Chemistry, 5e (Timberlake)Chapter 7 Chemical Reactions and Quantities
7.1 Multiple-Choice Questions
1) A chemical equation is balanced whenA) the total number of molecules is the same in reactants and products.B) the total number of ions is the same in reactants and products.C) the sum of the coefficients of the reactants is equal to the sum of the coefficients of the products.D) the number of atoms of each element is the same in reactants and products.E) the charge on each atom is the same in reactants and products.Answer: DObjective: 7.1Global Outcomes: GO2
2) In any balanced chemical equation, the number of each type of atom on both sides of the equation isA) doubled.B) the same.C) decreased by one.D) increased by one.E) dependent on the temperature.Answer: BObjective: 7.1Global Outcomes: GO2
3) Which of the following gives the balanced equation for this reaction?
10) In the following reaction, when the equation is correctly balanced, what is the correct coefficient for aluminum chloride?
Al(s) + Cl2(g) → AlCl3(s)
A) 1B) 2C) 3D) 4E) 5Answer: BObjective: 7.1Global Outcomes: GO2
Pentane (C5H12) reacts with oxygen (O2) to form carbon dioxide (CO2) and water (H2O) according to the following reaction. Answer the question(s) that follow about this reaction.
C5H12 + ? O2 → ? CO2 + ? H2O
11) What is the coefficient for oxygen in the balanced equation?A) 2 B) 4C) 5D) 6E) 8Answer: EObjective: 7.1Global Outcomes: GO2
12) What is the coefficient for carbon dioxide in the balanced equation?A) 2B) 4C) 5D) 6E) 8Answer: CObjective: 7.1Global Outcomes: GO2
13) What is the coefficient for water in the balanced equation?A) 2B) 4C) 5D) 6E) 8Answer: DObjective: 7.1Global Outcomes: GO2
14) In a ________ reaction, two or more elements or compounds form one product.A) decompositionB) single replacementC) dehydrationD) double replacementE) combinationAnswer: E
20) Which of the following is an oxidation-reduction reaction?A) CaCl2 + Na2SO4 → CaSO4 + 2NaClB) KOH + HNO3 → H2O + KNO3C) N2 + O2 → 2NOD) AgNO3 + NaCl → AgCl + NaNO3E) Al2(SO4)3 + 6KOH → 2Al(OH)3 + 3K2SO4Answer: CObjective: 7.3Global Outcomes: GO2
21) What is oxidized and what is reduced in the following reaction?
2Al(s) + 3Br2(g) → 2AlBr3(s)
A) Al is oxidized and Br2 is reduced.B) AlBr3 is reduced and Br2 is oxidized.C) Al is reduced and Br2 isoxidized.D) AlBr3 is reduced and Al is oxidized.E) AlBr3 is oxidized and Al is reduced.Answer: AObjective: 7.3Global Outcomes: GO2
22) Which of the following describes an oxidation reaction?A) loss of electrons or loss of oxygenB) loss of electrons or gain of oxygenC) loss of electrons or gain of hydrogenD) gain of electrons or gain of oxygenE) gain of electrons or loss of HAnswer: BObjective: 7.3Global Outcomes: GO2
23) In an oxidation-reduction reaction, the substance oxidized alwaysA) takes on oxygen atoms.B) shows a loss of electrons.C) gives up hydrogen atoms.D) shows a gain of electrons.E) becomes a charged species.Answer: BObjective: 7.3Global Outcomes: GO2
25) In an oxidation-reduction reaction, the substance reduced alwaysA) takes on oxygen atoms.B) shows a loss of electrons.C) gives up hydrogen atoms.D) shows a gain of electrons.E) becomes a charged species.Answer: DObjective: 7.3Global Outcomes: GO2
26) How many moles of iron are present in 3.15 × 1024 atoms of iron?A) 5.23 molesB) 1.90 molesC) 292 molesD) 0.523 molesE) 1.90 × 1048 moles Answer: AObjective: 7.4Global Outcomes: GO4
27) How many atoms of neon are present in 1.30 moles of neon?A) 3.15 × 1023
28) One mole of particles of any substance contains how many particles?A) 106
B) 3 × 10-10
C) 3 × 1010
D) 6.02 × 1023
E) 6.02 × 10-23
Answer: DObjective: 7.4Global Outcomes: GO4
29) Avogadro's number is the number ofA) particles in 1 mole of a substance.B) amu in 1 mole of a substance.C) grams in 1 mole of a substance.D) moles in 6.02 × 1023
grams of an element.
E) moles in 6.02 × 1023 amu of an element.
Answer: AObjective: 7.4Global Outcomes: GO4
30) How many molecules of water, H2O, are present in 75.0 g of H2O?A) 75.0 moleculesB) 4.17 moleculesC) 7.53 × 1024 molecules D) 2.51 × 1024
molecules
E) 5.02 × 1024 molecules
Answer: DObjective: 7.5Global Outcomes: GO4
31) How many hydrogen atoms are present in 75.0 g of H2O?A) 75.0 atomsB) 4.17 atomsC) 7.53 × 1024
33) One mole of helium gas has a mass ofA) 1.00 g.B) 2.00 g.C) 3.00 g.D) 4.00 g.E) 8.00 g.Answer: DObjective: 7.5Global Outcomes: GO4
34) How many moles of water, H2O, are present in 75.0 g of H2O?A) 4.41 molesB) 4.16 molesC) 75.0 molesD) 7.50 molesE) 1.35 × 103 moles Answer: BObjective: 7.5Global Outcomes: GO4
35) 0.100 mole of lithium has a mass of A) 3.00 g.B) 0.300 g.C) 6.94 g.D) 0.694 g.E) 0.700 g.Answer: DObjective: 7.5Global Outcomes: GO4
36) Calculate the molar mass of potassium chloride, KCl.A) 74.6 gB) 54.5 gC) 6.74 gD) 67.4 gE) 19.0 gAnswer: AObjective: 7.5Global Outcomes: GO4
37) What is the molar mass of copper(II) sulfate, CuSO4?A) 16.0 gB) 63.6 gC) 111.6 gD) 159.6 gE) 319.2 g
38) Calculate the molar mass of magnesium chloride, MgCl2. A) 24.3 gB) 95.2 gC) 125.9 gD) 59.8 gE) 70.0 gAnswer: BObjective: 7.5Global Outcomes: GO4
39) What is the molar mass of sodium phosphate, Na3PO4?A) 119 gB) 308 gC) 164 gD) 226 gE) 354 gAnswer: CObjective: 7.5Global Outcomes: GO4
40) How many moles of carbon atoms are there in 0.500 mole of C2H6?A) 0.500 molesB) 1.00 molesC) 3.00 molesD) 6.02 × 1023 molesE) 4.00 molesAnswer: BObjective: 7.5Global Outcomes: GO4
45) What is the molar mass of Mg3(PO4)2, a substance formerly used in medicine as an antacid?A) 71.3 gB) 118 gC) 150. gD) 214 gE) 263 gAnswer: EObjective: 7.5Global Outcomes: GO4
46) 4.00 moles of sodium have a mass ofA) 4.60 g.B) 11.0 g.C) 23.0 g.D) 44.0 g.E) 92.0 g.Answer: EObjective: 7.5Global Outcomes: GO4
47) How many moles of K2SO4 are in 15.0 g of K2SO4?A) 0.172 molesB) 2.61 × 103 molesC) 0.111 molesD) 0.0861 molesE) 0.119 molesAnswer: DObjective: 7.5Global Outcomes: GO4
48) 3.00 moles of NO2 have a mass ofA) 138 g.B) 46.0 g.C) 30.0 g.D) 90.0 g.E) 45.0 g.Answer: AObjective: 7.5Global Outcomes: GO4
49) 1.25 moles of PbO2 have a mass ofA) 191 g.B) 279 g.C) 178 g.D) 239 g.E) 299 g.Answer: EObjective: 7.5Global Outcomes: GO4
50) How many grams of Fe2O3 are there in 0.500 mole of Fe2O3?A) 79.9 gB) 35.9 gC) 63.8 gD) 51.9 gE) 160. gAnswer: AObjective: 7.5Global Outcomes: GO4
51) How many grams of glucose (C6H12O6) are in 3.55 moles of glucose?A) 180. gB) 639 gC) 103 gD) 426 gE) 50.7 gAnswer: BObjective: 7.5Global Outcomes: GO4
52) Given the following equation, what is the correct form of the conversion factor needed to convert the number of moles of O2 to the number of moles of Fe2O3
produced?
4Fe(s) + 3O2 (g) → 2Fe2O3(s)
A)
B)
C)
D)
E)
Answer: EObjective: 7.6Global Outcomes: GO4
For the question(s) that follow, consider the following equation.
2Mg + O2 → 2MgO
53) The number of moles of oxygen gas needed to react with 4.0 moles of Mg isA) 1.0 mole.B) 2.0 moles.C) 3.0 moles.D) 4.0 moles.E) 6.0 moles.Answer: BObjective: 7.6Global Outcomes: GO4
54) The number of moles of MgO produced when 0.20 mole of O2 reacts completely is
55) How many moles of magnesium are needed to react with 0.50 mole of O2?A) 0.50 moleB) 1.0 molesC) 2.0 molesD) 3.0 molesE) 4.0 molesAnswer: BObjective: 7.6Global Outcomes: GO4
56) When 4 moles of aluminum are allowed to react with an excess of chlorine gas, Cl2, how many moles of aluminum chloride are produced? A) 1 moleB) 2 molesC) 3 molesD) 4 molesE) 5 molesAnswer: DObjective: 7.6Global Outcomes: GO4
57) In the reaction of nitrogen gas, N2, with hydrogen gas, H2, to form ammonia gas, NH3 , how many moles of hydrogen are needed to react with two moles of nitrogen?A) 2 molesB) 4 molesC) 6 molesD) 8 molesE) 10 molesAnswer: CObjective: 7.6Global Outcomes: GO4
For the question(s) that follow, consider the following balanced equation.
Mg3N2(s) + 6H2O(l) → 3Mg (OH)2(s) + 2NH3(g)
58) What is the correct form of the conversion factor needed to convert the number of moles of H2O to the number of moles of NH3
produced?
A)
B)
C)
D)
E)
Answer: AObjective: 7.6Global Outcomes: GO4
59) When 2 moles of Mg3N2 are allowed to react, how many moles of H2O also react?A) 1 moleB) 4 molesC) 6 molesD) 8 molesE) 12 molesAnswer: EObjective: 7.6Global Outcomes: GO4
For the question(s) that follow, consider the following equation.
2Mg + O2 → 2MgO
60) How many grams of MgO are produced when 40.0 grams of O2 react completely with Mg?A) 30.4 g B) 50.4 gC) 60.8 gD) 101 gE) 201 gAnswer: DObjective: 7.7Global Outcomes: GO4
For the question(s) that follow, consider the following balanced equation.
Mg3N2(s) + 6H2O(l) → 3Mg (OH)2(s) + 2NH3(g)
61) How many grams of H2O are needed to produce 150 g of Mg(OH)2?A) 46 gB) 18 gC) 130 gD) 93 gE) 23 g Answer: DObjective: 7.7Global Outcomes: GO4
62) When 36.0 g of H2O react, how many grams of NH3 are produced? A) 34.0 gB) 10.0 gC) 5.67 gD) 11.3 gE) 102 gAnswer: DObjective: 7.7Global Outcomes: GO4
63) How many grams of hydrogen are needed to produce 1.80 g of water according to this equation?
64) In the reaction of silver nitrate with sodium chloride, how many grams of silver chloride will be produced from 100. g of silver nitrate when it is mixed with an excess of sodium chloride? The equation for the reaction is below.
75) What type of reaction is: CH4 + 2O2 → CO2 + 2H2O + 218 kcal?A) an endothermic reactionB) an exothermic reactionC) a single replacement reactionD) a combination reactionE) a decomposition reactionAnswer: BObjective: 7.9Global Outcomes: GO2
76) How many kcal are produced when 32.0 g of CH4 react?
78) For the reaction: 2H2O(l) + 137 kcal → 2H2 (g) + O2 (g), how many kcal are needed to react 50.0 g H2O(l)?A) 380. kcalB) 137 kcalC) 274 kcalD) 190. kcalE) 760. kcalAnswer: DObjective: 7.9Global Outcomes: GO4
79) If the reaction shown below is exothermic, the energy level of the reactants is
H2 + O2 → 2H2O
A) lower than that of the products.B) higher than that of the products.C) the same as that of the products.D) possibly lower, possibly higher than that of the products.E) higher than the activation energy of the reaction.Answer: BObjective: 7.9Global Outcomes: GO2
80) In an endothermic reactionA) heat flows out of the system.B) energy is absorbed by the system.C) the temperature of the system increases.D) the products have less energy that the reactants.E) the products have the same energy that the reactants.Answer: BObjective: 7.9Global Outcomes: GO2
81) Any reaction that absorbs 150 kcal of energy can be classified asA) endothermic.B) exothermic.C) activated.D) reduction.E) oxidation.Answer: AObjective: 7.9Global Outcomes: GO2
82) The ________ is the energy difference between reactants and products in a chemical reaction.A) transition energyB) activation energyC) product energyD) overall energyE) heat of reactionAnswer: EObjective: 7.9Global Outcomes: GO2
83) The ________ is the minimum energy needed for a chemical reaction to begin.A) reaction energyB) activation energyC) energy of reactantsD) energy of productsE) heat of reactionAnswer: BObjective: 7.9Global Outcomes: GO2
84) A reaction that releases energy as it occurs is classified as a(n)A) endothermic reaction.B) exothermic reaction.C) oxidation-reduction reaction.D) catalyzed reaction.E) decomposition reaction.Answer: BObjective: 7.9Global Outcomes: GO2
1) In this reaction, what is the correct coefficient for hydrogen gas?
? H2 + ? O2 → ? H2O
A) 1B) 2C) 3D) 4E) 5Answer: BObjective: 7.1Global Outcomes: GO4
Barium chloride and sodium sulfate react according to the following equation.
BaCl2 + Na2SO4 → BaSO4 + 2NaCl
Answer the question(s) that follow about this reaction.
2) How many moles of barium sulfate are produced from 0.100 mole of barium chloride?A) 0.0100 moleB) 0.100 moleC) 0.200 moleD) 1.00 moleE) 2.00 molesAnswer: BObjective: 7.6Global Outcomes: GO4
3) How many grams of barium sulfate can be produced from 20.8 g of barium chloride?A) 1.37 gB) 2.33 gC) 23.3 gD) 137 gE) 233 gAnswer: CObjective: 7.7Global Outcomes: GO4
4) How many grams of barium chloride are needed to make 100. grams of barium sulfate?A) 44.9 gB) 89.2 gC) 208.3 gD) 233.3 gE) 46.6 gAnswer: BObjective: 7.7Global Outcomes: GO4
Answer the question(s) that follow about the following reaction.
2H2O2 → 2H2O + O2
5) How many moles of oxygen gas can 0.88 mole of hydrogen peroxide (H2O2) produce, if decomposition is complete?A) 0.50 moleB) 0.88 moleC) 1.8 molesD) 2.0 molesE) 0.44 moleAnswer: EObjective: 7.6Global Outcomes: GO4
6) How many grams of water will 100. grams of hydrogen peroxide (H2O2) produce?A) 3600 gB) 360. gC) 5.88 gD) 52.9 gE) 106 gAnswer: DObjective: 7.7Global Outcomes: GO4
7) How many grams of hydrogen peroxide (H2O2) are needed to produce 25.0 g of oxygen?A) 106 gB) 26.6 gC) 5.88 gD) 25.0 gE) 53.1 gAnswer: EObjective: 7.7Global Outcomes: GO4
8) How many moles of hydrogen peroxide (H2O2) are needed to produce 5.0 moles of water?A) 1.0 moleB) 2.0 molesC) 4.0 molesD) 5.0 molesE) 8.0 molesAnswer: DObjective: 7.6Global Outcomes: GO4
6) The molar mass of copper(II) nitrate, Cu(NO3)2 is ________.Answer: 187.6 gObjective: 7.5Global Outcomes: GO4
7) What is the mass of 1 mole of argon gas?Answer: 40.0 gObjective: 7.5Global Outcomes: GO4
8) What is the mass of 1 mole of helium gas?Answer: 4.00 gObjective: 7.5Global Outcomes: GO4
9) Acetylene gas, C2H2, reacts with oxygen according to the following equation. If 1.00 mole of acetylene reacts completely with sufficient oxygen, how many moles of carbon dioxide are produced?
2C2H2 + 5O2 → 4CO2 + 2H2OAnswer: 2.00 moles of CO2 Objective: 7.6Global Outcomes: GO4
7) The mass of one mole of water is 18.0 g.Answer: TRUEObjective: 7.5Global Outcomes: GO4
8) The molar mass of chlorine gas is 35.5 g.Answer: FALSEObjective: 7.5Global Outcomes: GO4
9) The molar mass of copper(II) chloride is 134.5 g.Answer: TRUEObjective: 7.5Global Outcomes: GO4
10) In the reaction of hydrogen gas with oxygen gas to produce water, 1 mole of oxygen gas can produce 2 moles of water, given sufficient hydrogen available.Answer: TRUEObjective: 7.6Global Outcomes: GO4
11) In the reaction of hydrogen gas with oxygen gas to produce water, 16.0 g of oxygen gas can produce 9.00 g of water, given sufficient hydrogen available.