Deck 5: Chemical Reactions

Question 1

Aspartic acid is an amino acid used to synthesize proteins. What is the molar mass of aspartic acid shown below?

A)121.09 g/mol
B)133.11 g/mol
C)117.0 g/mol
D)126.04 g/mol
E)132.09 g/mol

Answer 1

B

Question 2

Suppose the theoretical yield in a reaction is 10.5 g and the percent yield is 75.5%. What is the actual yield of product obtained?

A)793 g
B)7.93 g
C)13.9 g
D)0.139 g

Answer 2

B

Question 3

How many moles of carbon dioxide are in 211 g of carbon dioxide?

A)929 mol of CO₂
B)4.79 mol of CO₂
C)167 mol of CO₂
D)0.209 mol of CO₂

Answer 3

B

Question 4

Write a balanced chemical equation for the reaction of acetone (C₃H₆O)with oxygen (O₂)to form carbon dioxide (CO₂)and water (H₂O).

A)C₃H₆O + O₂ $\rightarrow$ CO₂ + H₂O
B)C₃H₆O + 4 O₂ $\rightarrow$ 3 CO₂ + 3 H₂O
C)3 CO₂ + 3 H₂O $\rightarrow$ C₃H₆O + 4 O₂
D)6 C₃H₆O + 8 O₂ $\rightarrow$ 6 CO₂ + 6 H₂O

Question 5

Consider the oxidation of sodium metal to sodium oxide described by the balanced equation: 4 Na + O₂ $\rightarrow$ 2 Na₂O. What is the theoretical yield of Na₂O in grams from 9.0 mol of O₂?

A)11 g of Na₂O
B)410 g of Na₂O
C)1, 100 g of Na₂O
D)280 g of Na₂O
E)560 g of Na₂O

Question 6

The law of conservation of mass states that

A)atoms cannot be created or destroyed in a chemical reaction.
B)molecules cannot be created or destroyed in a chemical reaction.
C)compounds cannot be created or destroyed in a chemical reaction.
D)heat cannot be created or destroyed in a chemical reaction.

Question 7

What is the formula weight of KCl?

A)74.55 amu
B)66.42 amu
C)36.00 amu
D)1386 amu

Question 8

In the chemical equation 2 Co(NO₃)₃ + 3 (NH₄)₂S $\rightarrow$ Co₂S₃ + 6 NH₄NO₃ , how many nitrogen atoms are on each side of the equation?

A)2
B)3
C)6
D)12
E)16

Question 9

Which sample contains the largest number of molecules?

A)100 g of CO₂
B)100 g of CH₄
C)100 g of CBr₄
D)100 g of CHBr₃

Question 10

How many moles of sulfur trioxide are formed from 3 moles of oxygen using the given balanced equation? 2 SO₂ + O₂ $\rightarrow$ 2 SO₃

A)1 mol of SO₃
B)2 mol of SO₃
C)3 mol of SO₃
D)5 mol of SO₃
E)6 mol of SO₃

Question 11

What is the mass of 3.81 mol of PH₃?

A)34.0 g
B)3.81 g
C)8.92 g
D)130. g
E)0.112 g

Question 12

Consider the reaction: 2 Al(OH)₃ + 3 H₂SO₄ $\rightarrow$ Al₂(SO₄)₃ + 6 H₂O. How many grams of Al₂(SO₄)₃ are generated when 152 g of H₂SO₄ reacts?

A)530. g of Al₂(SO₄)₃
B)1590 g of Al₂(SO₄)₃
C)177 g of Al₂(SO₄)₃
D)43.6 g of Al₂(SO₄)₃
E)131 g of Al₂(SO₄)₃

Question 13

The Greek letter delta ( $\Delta$ )may be written over the reaction arrow in a chemical equation to indicate that

A)heat is generated when the reaction occurs.
B)a catalyst is needed for the reaction to occur.
C)water is needed for the reaction to occur.
D)heat is needed for the reaction to occur.

Question 14

How many moles of chloroethylene (C₂H₃Cl)contain 5.47 × 10²⁶ molecules?

A)3.29 × 10⁵⁰ mol of C₂H₃Cl
B)5.47 × 10²⁶ mol of C₂H₃Cl
C)909 mol of C₂H₃Cl
D)5450 mol of C₂H₃Cl

Question 15

What is the formula weight of Co(NO₃)₃?

A)88.94 amu
B)244.96 amu
C)216.94 amu
D)148.96 amu
E)196.96 amu

Question 16

A balanced chemical equation tells the number of _____ of each reactant that combine and the number of _____ of each product formed.

A)grams, grams
B)grams, moles
C)moles, grams
D)moles, moles

Question 17

How many carbon atoms are in 3.85 mol of carbon?

A)3.85 carbon atoms
B)23.2 carbon atoms
C)6.02 × 10²³ carbon atoms
D)2.32 × 10²⁴ carbon atoms
E)6.40 × 10^-24 carbon atoms

Question 18

Which chemical equation is properly balanced?

A)SO₂ + O₂ + H₂O $\rightarrow$ H₂SO₄
B)2 SO₂ + O₂ + 2 H₂O $\rightarrow$ 2 H₂SO₄
C)SO₂ + O₂ + 4 H₂O $\rightarrow$ 2 H₂SO₄
D)4 SO₂ + O₂ + 4 H₂O $\rightarrow$ 4 H₂SO₄

Question 19

How many iron atoms are in 0.32 mol of Fe₂O₃?

A)3.9 × 10²³ iron atoms
B)3.9 iron atoms
C)6.02 × 10²³ iron atoms
D)1.9 × 10²³ iron atoms
E)1.1 × 10^-24 iron atoms

Question 20

How many moles of sulfur trioxide are formed from 3 moles of sulfur dioxide using the given balanced equation? 2 SO₂ + O₂ $\rightarrow$ 2 SO₃

A)1 mol of SO₃
B)2 mol of SO₃
C)3 mol of SO₃
D)5 mol of SO₃
E)6 mol of SO₃

Question 21

The conversion factor shown below was obtained from the balanced chemical equation: 4 KO₂(s)+ 2 CO₂(g) $\rightarrow$ 2 K₂CO₃(s)+ 3 O₂(g). This conversion factor would be used to calculate which of the following?

A)the amount of KO₂ required to react with a certain amount of O₂
B)the amount of O₂ that can react with a certain amount of KO₂
C)the amount of O₂ that can be produced from a certain amount of KO₂
D)the amount of KO₂ that is required to produce a certain amount of O₂

Question 22

How many grams of oxygen gas are required to completely react with 77.28 g of ethane (C₂H₆)in the balanced redox reaction: 2 C₂H₆(g)+ 7 O₂(g) $\rightarrow$ 4 CO₂(g)+ 6 H₂O(g)?

A)77.28 g of O₂(g)
B)23.50 g of O₂(g)
C)143.9 g of O₂(g)
D)8.995 g of O₂(g)
E)287.8 g of O₂(g)

Question 23

Tin (II)fluoride can be made by the following reaction: Sn(s)+ 2 HF(g) $\rightarrow$ SnF₂(s)+ H₂(g). What is the maximum amount of SnF₂ that can be produced when 0.480 moles of Sn are mixed with 0.720 moles of HF?

A)0.360 moles of SnF₂
B)0.480 moles of SnF₂
C)0.600 moles of SnF₂
D)0.720 moles of SnF₂
E)1.20 moles of SnF₂

Question 24

The chemical equation: KClO₃(s) $\rightarrow$ KCl(s)+ O₂(g)is not balanced. Balance this equation, then select the statement that best describes the balanced equation.

A)The balanced equation will have six atoms of oxygen on each side of the equation.
B)The balanced equation will have one atom of chlorine on each side of the equation.
C)The balanced equation will have an O₃ on the product side of the equation.
D)The balanced equation will have a coefficient of 1 in front of KCl.

Question 25

In the balanced redox reaction: 2 C₂H₆(g)+ 7 O₂(g) $\rightarrow$ 4 CO₂(g)+ 6 H₂O(g), which species is oxidized?

A)C₂H₆(g)
B)O₂(g)
C)CO₂(g)
D)H₂O(g)

Question 26

What is the molar mass of the compound show below?

A)90.13 amu
B)90.13 g/mol
C)93.13 amu
D)93.13 g/mol
E)91.14 g/mol

Question 27

Identify the species that is oxidized and the species that is reduced in the reaction: 2 I^- + Cl₂ $\rightarrow$ 2 Cl^- + I₂

A)I^- is oxidized and Cl₂ is reduced.
B)Cl₂ is oxidized and I^- is reduced.
C)I₂ is oxidized and Cl^- is reduced.
D)Cl₂ is oxidized and Cl^- is reduced.
E)I₂ is oxidized and I^- is reduced.

Question 28

How many moles of sodium chloride (table salt, NaCl, molar mass 58.44 g/mol)are contained in a 1.00 lb box of table salt?

A)26, 500 mol of NaCl
B)4.68 × 10²⁴ mol of NaCl
C)58.44 mol NaCl
D)7.77 mol of NaCl
E)0.129 mol of NaCl

Question 29

In the balanced redox reaction: 2 C₂H₆(g)+ 7 O₂(g) $\rightarrow$ 4 CO₂(g)+ 6 H₂O(g), which species is reduced?

A)C₂H₆(g)
B)O₂(g)
C)CO₂(g)
D)H₂O(g)

Question 30

Potassium metal (K)reacts violently when added to water according to the balanced equation: 2 K(s)+ 2 H₂O(l) $\rightarrow$ 2 KOH(aq)+ H₂(g). How many moles of H₂O are needed to react completely with 7.54 mol of K?

A)2 mol of H₂O
B)7.54 mol of H₂O
C)15.1 mol of H₂O
D)3.77 mol of H₂O

Question 31

Which quantity has the greatest mass?

A)2.0 mol of Na
B)2.0 mol of Na₂O
C)2.0 mol of NaCl
D)2.0 mol of O₂
E)All of these quantities have the same mass.

Question 32

Consider the oxidation of sodium metal to sodium oxide described by the balanced equation: 4 Na + O₂ $\rightarrow$ 2 Na₂O. If 2.55 mol of sodium reacts, and 75.0 g of Na₂O is produced, what is the percent yield?

A)94.9% yield
B)34.0% yield
C)47.5% yield
D)190.% yield

Question 33

How many carbon atoms are in 77.28 g of ethane (C₂H₆)?

A)2.570 carbon atoms
B)5.140 carbon atoms
C)3.094 × 10²⁴ carbon atoms
D)1.548 × 10²⁴ carbon atoms
E)1.238 × 10²⁵ carbon atoms

Question 34

Blimps are essentially very large helium filled balloons. If a blimp contains 536 kg of helium, how many helium atoms are present inside the blimp?

A)134, 000 He atoms
B)8.9 x 10^-19 He atoms
C)8.06 x 10²⁸ He atoms
D)3.23 x 10²⁶ He atoms

Question 35

In the balanced redox reaction: 2 Cu(s)+ S(s) $\rightarrow$ Cu₂S(s), how many electrons are gained or lost by each copper atom?

A)each copper atom gains two (2)electrons
B)each copper atom gains one (1)electron
C)each copper atom loses one (1)electron
D)each copper atom loses two (2)electrons

Question 36

Consider the mixture of Cl₂ and F₂ in a closed container as illustrated below. What will the contents of the container look like if the molecules undergo the reaction: Cl₂(g)+ 3 F₂(g) $\rightarrow$ 2 ClF₃(g)?

A)
B)
C)
D)

Question 37

If a synthesis has four steps and each step has a 75% yield (0.75 written as a decimal), what is the overall percent yield?

A)75%
B)19%
C)56%
D)32%
E)42%

Question 38

Sodium fluoride can be produced from the reaction between sodium metal and fluorine gas. Which of the following represents the balanced chemical equation for this reaction?

A)2 Na(s)+ F₂(g) $\rightarrow$ 2 NaF(s)
B)Na⁺(s)+ F^-(g) $\rightarrow$ NaF(s)
C)Na(s)+ F₂(g) $\rightarrow$ NaF₂(s)
D)2 Na(s)+ F₂(g) $\rightarrow$ Na₂F₂(s)

Question 39

What is the mass of 3.4 × 10²⁰ molecules of ethanol (C₂H₆O)expressed in milligrams?

A)0.026 mg of ethanol
B)26, 000 mg of ethanol
C)0.012 mg of ethanol
D)26 mg of ethanol

Question 40

What are the two half reactions that show how many electrons are gained or lost by each species in the reaction:
Ni²⁺(aq)+ Mg(s) $\rarr$ Ni(s)+ Mg²⁺(aq)?

A)Ni²⁺(aq)+ e^- $\rarr$ Ni(s)and Mg(s) $\rarr$ Mg²⁺(aq)+ e^-

B)Ni²⁺(aq)+ 2 e^- $\rarr$ Ni(s)and Mg(s) $\rarr$ Mg²⁺(aq)+ 2 e^-

C)Ni²⁺(aq) $\rarr$ Ni(s)+ 2 e^- and Mg(s)+ 2 e^- $\rarr$ Mg²⁺(aq)

D)Ni²⁺(aq) $\rarr$ Ni(s)+ e^- and Mg(s)+ e^- $\rarr$ Mg²⁺(aq)

E)Ni²⁺(aq)+ 2 e^- $\rarr$ Ni(s)and Mg(s)+ 2 e^- $\rarr$ Mg²⁺(aq)

Question 41

The subscripts in chemical formulas are changed in order to balance a chemical equation.

Question 42

A student runs the reaction: LiOH + CO₂ $\rightarrow$ LiHCO₃. The reaction consumes 45.0 g LiOH and produces 72.8 g of LiHCO₃. Which of the statements concerning this reaction is true?

A)The actual yield of the product is 72.8 g LiHCO₃.
B)The theoretical yield of the product is 72.8 g LiHCO₃.
C)The theoretical yield of the product is 117.8 g LiHCO₃.
D)The percent yield of the reaction is 61.8%.

Question 43

In the reaction: Ni²⁺(aq)+ Mg(s) $\rightarrow$ Ni(s)+ Mg²⁺(aq), the species that undergoes reduction is Mg(s).

Question 44

The molar mass of CaCO₃ is greater than the molar mass of Ca(NO₃)₂.

Question 45

Combustion reactions are redox reactions.

Question 46

In the reaction: Ni²⁺(aq)+ Mg(s) $\rightarrow$ Ni(s)+ Mg²⁺(aq), the oxidizing agent is Ni²⁺(aq).

Question 47

All chemical reactions convert one substance into another.

Question 48

The balanced reaction: 4 NO₂ + O₂ + 2 H₂O $\rightarrow$ 4 HNO₃ states that four grams of nitrogen dioxide reacts with each gram of oxygen.

Question 49

Oxidation is the gain of electrons by an atom.

Question 50

In calculating the percent yield, both the actual yield and theoretical yield must be in units of grams.

Question 51

The actual yield is the amount of product expected from a given amount of reactant based on the coefficients in the balanced chemical equation.

Question 52

A chemical equation is balanced by adding coefficients in front of some formulas so that the number of atoms of each element is equal on both sides of the equation.

Question 53

A mole of copper atoms has more atoms than a mole of lead atoms.

Question 54

One mole of oxygen molecules contains more atoms than one mole of lead atoms.

Question 55

Assume that the mixture of substances in Figure 1 undergoes a chemical reaction. Which diagram represents a product mixture that is consistent with the Law of Conservation of Mass?

A)
B)
C)
D)It is impossible to predict based on the information given.

Question 56

The balanced reaction: 4 Fe(s)+ 3 O₂(g) $\rightarrow$ 2 Fe₂O₃(s)is an oxidation-reduction reaction.

Question 57

The balanced reaction: 4 NO₂ + O₂ + 2 H₂O $\rightarrow$ 4 HNO₃ states that four moles of nitrogen dioxide react with each mole of oxygen.

Question 58

Beaker A contains 1 mole of iron atoms, and Beaker B contains 1 mole of lead atoms. Which statement concerning these two samples is known with certainty?

A)Beakers A and B contain samples with the same molar mass.
B)Beakers A and B contain an equal number of atoms.
C)Beakers A and B contain an equal volume of atoms.
D)Beakers A and B contain equal masses of atoms.

Question 59

A mole is a quantity that contains 6.02 × 10^-23 atoms, molecules, or ions.

Question 60

The formula weight of a compound is the sum of the atomic weights of all the atoms in a compound, reported in atomic mass units.

Question 61

Consider the unbalanced chemical equation: NH₃ + O₂ $\rightarrow$ NO + H₂O. It requires 55.4 g of NH₃ to completely react with 156 g of O₂.

Question 62

The reaction: Mg(s)+ 2 HBr(aq) $\rightarrow$ MgBr₂(s)+ H₂(g)is an oxidation-reduction reaction.

Question 63

To multiply two numbers in scientific notation, multiply the coefficients together and multiply the exponents in the powers of 10.

Question 64

A chemical equation is an expression that uses chemical formulas and other symbols to illustrate what _____ constitute the starting materials in a reaction and what _____ are formed.

Question 65

A 100-g sample of the compound below contains less than 6.02 × 10²³ molecules.

Question 66

In the reaction: Ni²⁺(aq)+ Mg(s) $\rightarrow$ Ni(s)+ Mg²⁺(aq), two electrons are transferred from Ni² to Mg.

Question 67

Consider the balanced reaction: 2 A + B $\rightarrow$ C, where the molar mass of B is less than the molar mass of A. It requires a smaller mass of A to completely react with given mass of B.

Question 68

The actual yield of a product in a chemical reaction should not exceed its theoretical yield.

Question 69

The molar mass of dibromomethane (CH₂Br₂)is larger than the molar mass of dichloromethane (CH₂Cl₂).

Question 70

One term in a balanced chemical equation contains the coefficient 4 in front of the formula Mg₃(PO₄)₂. This term represents that there are 12 Mg atoms, 4 P atoms and 16 O atoms in this term.

Question 71

The mass of one ethanol (C₂H₆O)molecule is 7.65 × 10^-23 grams.

Question 72

A chemical change alters the chemical composition of a substance, and therefore a new substance is produced.

Question 73

The electric current generated in batteries used for portable electronic devices and pacemakers results from redox reactions.

Question 74

A 100-g sample of the compound below contains greater than one mole of molecules.

Question 75

In a chemical reaction, the actual yield of a product may be reduced by side reactions.

Question 76

In redox reactions, metals tend to undergo oxidation.

Question 77

Consider the balanced reaction: 4 NO₂ + O₂ + 2 H₂O $\rightarrow$ 4 HNO₃. If 100. g of NO₂ is placed in a reaction vessel the theoretical yield of nitric acid (HNO₃)collected will be 137 g.

Question 78

To determine the overall percent yield in a synthesis that has more than one step, subtract the percent yield for each step from 100% yield.

Question 79

A 200.-mg ibuprofen (C₁₃H₁₈O₂)tablet contains greater than one mole of ibuprofen molecules.

Question 80

When the mass of a substance produced in a reaction must be calculated, first its number of moles is determined using mole ratios, and then Avogadro's number is used to convert moles to grams.