Deck 4: Calculations, Chemical Changes, and the Chemical Equation

Question 1

Which statement best describes the Law of Conservation of Mass?

A)The masses of the reactants in a chemical reaction are always equal.
B)The mass of the product formed in a chemical reaction is determined by the limiting reactant.
C)The mass of the product formed in a chemical reaction is equal to the mass of the reactant in the smallest amount.
D)Matter is neither gained nor lost in a chemical reaction.
E)When two or more products are formed in a chemical reaction, their masses will always be equal.

Answer 1

Matter is neither gained nor lost in a chemical reaction.

Question 2

The unbalanced equation for the combustion of octane, a component of gasoline, is shown below.What would be the coefficient of carbon dioxide once the equation is balanced? C₈H₁₈(l) + O₂(g) → CO₂(g) + H₂O(l)

A)8
B)25
C)16
D)18
E)No coefficient would be shown.

Answer 2

16

Question 3

Which notation properly indicates how two molecules of diatomic oxygen would be represented in a chemical equation?

A)(O₂)₂
B)O₄
C)2O₂
D)O₂O₂
E)All of the choices are correct.

Answer 3

2O₂

Question 4

The chemical equation below is not balanced.Balance the equation, then determine which statement concerning the balanced equation is TRUE. KClO₃(s) → KCl(s) + O₂(g)

A)The balanced equation will have an equal number of moles of reactants and products.
B)The balanced equation will have three atoms of oxygen on each side.
C)The balanced equation will have one atom of potassium on each side.
D)The balanced equation will have two atoms of chlorine on each side.
E)The balanced equation will contain a substance whose coefficient is 1.

Question 5

Hydrogen fluoride will react with glass (silicon dioxide, SiO₂) according to the equation below.What mass of HF is required to react completely with 16.0 g of glass?[Molar masses: Si, 28.09 g/mol; F, 19.00 g/mol; H, 1.01 g/mol; O, 16.00 g/mol] 4HF(g) + SiO₂(s) → SiF₄(g) + 2H₂O(g)

A)5.33 g
B)21.3 g
C)64.0 g
D)80.0 g
E)320 g

Question 6

How many molecules of water are present in a 5.65 mole sample of water?

A)4.00 × 10²⁴ molecules
B)1.07 × 10²³ molecules
C)3.40 × 10²⁴ molecules
D)9.39 × 10⁻²⁴ molecules
E)4.00 × 10²⁵ molecules

Question 7

Consider the chemical equation shown below.How many moles of oxygen gas are needed to react with hydrogen to form one mole of water? 2H₂(g) + O₂(g) → 2H₂O(l)

A)0.5 mol
B)1 mol
C)3 mol
D)4 mol
E)5 mol

Question 8

What is the mass of 4.00 moles of helium, the gas commonly used to fill party balloons and lighter-than-air ships?

A)4 amu
B)4.00 g
C)8.00 g
D)16.0 g
E)2.41 × 10²⁴ g

Question 9

Aluminum metal and oxygen gas are produced when aluminum oxide is heated at high temperature.Which statement concerning this chemical change is true?

A)Aluminum oxide is the product in this reaction.
B)This reaction is a combustion reaction.
C)Aluminum and oxygen are the reactants in this reaction.
D)This reaction is a decomposition reaction.
E)The chemical equation for this reaction is: AlO₂(s) → Al(s) + O₂(g).

Question 10

Which symbol, often found in chemical equations, indicates that a substance is dissolved in water?

A)(w)
B)(l)
C)(aq)
D)(d)
E)(_∆)

Question 11

The fluoride rinse in dental offices usually contains sodium fluoride.Sodium fluoride can be prepared from the reaction between sodium metal and fluorine gas.Which of the following properly represents the balanced chemical equation for this reaction?

A)Na(s) + F₂(g) → NaF₂(s)
B)Na(s) + F(g) → NaF(s)
C)7Na(s) + F(g) → Na₇F(s)
D)2Na(s) + F₂(g) → 2Na₂F(s)
E)2Na(s) + F₂(g) → 2NaF(s)

Question 12

A sample of aluminum contains 2.91 × 10²² atoms of aluminum.What is the mass of this sample? [Molar mass: Al, 26.98 g/mol]

A)0.767 g
B)1.30 g
C)558 g
D)1.08 × 10²¹ g
E)7.85 × 10²³g

Question 13

What is the mass of one mole of diatomic hydrogen, H₂?

A)1.01 amu
B)2.02 amu
C)1.01 g
D)2.02 g
E)6.022 × 10²³ g

Question 14

The chemical equation below is unbalanced.What is the coefficient of water when the equation is balanced? Mg(OH)₂(s) + HCl(g) → MgCl₂(s) + H₂O(l)

A)1
B)2
C)3
D)4
E)No coefficient would be shown.

Question 15

Glucose (C₆H₁₂O₆) is an important energy-rich compound produced by photosynthesis according to the equation below.What mass of glucose can be produced from 2.61 mol of CO₂ and the necessary water? [Molar masses: C, 12.01 g/mol; H, 1.01 g/mol; O, 16.00 g/mol] 6CO₂(g) + 6H₂O(l) → C₆H₁₂O₆(l) + 6O₂(g)

A)0.0128 g
B)0.0869 g
C)69.0 g
D)78.4 g
E)414 g

Question 16

Which has the greatest mass, one atom of carbon, one atom of hydrogen, or one atom of lithium?

A)one atom of carbon
B)one atom of hydrogen
C)one atom of lithium
D)All three atoms have the same mass.
E)It is impossible to determine.

Question 17

The mass of one atom of oxygen is 16.00 amu.What is the mass of one mole of elemental oxygen (O₂)?

A)32.00 amu
B)32.00 g
C)9.64 × 10²⁴ g
D)1.93 × 10²⁵ g
E)1.88 × 10²² g

Question 18

Which of the following statements concerning a voltaic cell is FALSE?

A)The oxidation half reaction occurs at the cathode.
B)A voltaic cell uses an oxidation-reduction reaction to produce electrical energy.
C)The cell consists of two half cells.
D)The anode and the cathode are separated by a salt bridge.
E)At the anode a substance will lose electrons.

Question 19

Upon mixing a clear colorless BaCl₂ solution with a clear, colorless Na₂SO₄ solution according to the reaction below, a student observes a white cloudiness form.What is responsible for the cloudiness that is observed? BaCl₂(aq) + Na₂SO₄(aq) → BaSO₄(s) + 2NaCl(aq)

A)NaCl
B)BaSO₄
C)BaCl₂
D)Na₂SO₄
E)It is impossible to tell without doing the reaction oneself.

Question 20

What is the general term for the process in which a chemical species loses electrons?

A)oxidation
B)reduction
C)condensation
D)Lewis base
E)decomposition

Question 21

What mass of sodium hydroxide is necessary to react with a solution containing 73.00 g HCl, according to the chemical equation below? [Molar masses: NaOH, 39.99 g/mol; HCl, 36.45 g/mol] NaOH(aq) + HCl(aq) → NaCl(aq) + H₂O(l)

A)80.09 g
B)66.54 g
C)39.99 g
D)1.850 g
E)7.445 g

Question 22

How many iron atoms are present in 0.552 mol of iron?

A)2.798 × 10²⁴
B)6.02 × 10²³
C)27.98
D)3.32 × 10²³
E)55.85

Question 23

How is the reaction shown below best classified? Ca(s) + 2HCl(aq) → CaCl₂(g) + H₂(g)

A)decomposition
B)combination
C)single-replacement
D)double-replacement
E)precipitation

Question 24

How many moles of Au atoms are present in one ounce of pure gold? [1 oz = 28.4 g]

A)1.97 × 10² mol
B)6.94 mol
C)0.144 mol
D)0.0721 mol
E)5.08 × 10^-3 mol

Question 25

A sample of sulfur contains 1.81 × 10²⁴ atoms of sulfur.How many moles of sulfur does this represent?

A)1.81 mol
B)3.01 mol
C)0.333 mol
D)1.09 mol
E)1.77 mol

Question 26

How is the reaction shown below best classified? 2HgO(s) → 2Hg(l) + O₂(g)

A)decomposition
B)combination
C)single-replacement
D)double-replacement
E)combustion

Question 27

Diamond is a pure form of the element carbon.If a 2 carat diamond has a mass of 0.396 g, how many carbon atoms are contained in this diamond?

A)3.97 × 10²² atoms
B)6.58 × 10⁻²⁵ atoms
C)1.99 × 10²³ atoms
D)1.99 × 10²² atoms
E)2.38 × 10²³ atoms

Question 28

Dinitrogen monoxide, or laughing gas (N₂O), is used as a dental anesthetic and as an aerosol propellant.How many molecules of N₂O are present in a 12.6 g sample of the compound?

A)1.72 × 10²³ molecules
B)1.289 molecules
C)3.34 × 10²⁶ molecules
D)7.59 × 10²⁴ molecules
E)5.14 × 10²³ molecules

Question 29

When the equation below is balanced with the lowest possible whole number coefficients, what is the sum of the coefficients? Ca(s) + HCl(g) → CaCl₂(s) + H₂(g)

A)2
B)4
C)5
D)8
E)10

Question 30

Magnesium hydroxide, Mg(OH)₂, as "Milk of Magnesia" can be used to neutralize excess stomach acid, represented by HCl(aq) according to the chemical equation below. Mg(OH)₂(s) + 2HCl(aq) → MgCl₂(aq) + 2H₂O(l)
When 5.00 g of HCl are combined with an excess of Mg(OH)₂, what mass of MgCl₂ can be produced? [Molar masses: H, 1.01 g/mol; O, 16.00 g/mol; Mg, 24.31 g/mol; Cl, 35.45 g/mol]

A)13.1 g
B)6.53 g
C)0.957 g
D)2.50 g
E)70.5 g

Question 31

To convert a given number of moles into the number of atoms, one would multiply by which of the following factors?

A)6.022 × 10²³ atoms/1 mol
B)1 mol/6.022 × 10²³ atoms
C)1.66 × 10^-24 atoms/1 mol
D)1 mol/1.66 × 10^-24 atoms
E)molar mass

Question 32

How many atoms of sulfur are present in a 155 g sample of sulfur? [Molar mass: S, 32.06 g/mol]

A)2.91 × 10²⁴ atoms
B)6.02 × 10²³ atoms
C)3.01 × 10²³ atoms
D)2.91 × 10²³ atoms
E)2.01 × 10²³ atoms

Question 33

What is the mass of a 0.150 mole sample of sulfur?

A)5.17 g
B)4.68 g
C)214 g
D)0.208 g
E)4.81 g

Question 34

Cis-platin is a chlorine-containing chemotherapy agent with the formula Pt(NH₃)₂Cl₂.What is the mass of one mole of cis-platin?

A)283.02 g/mol
B)286.05 g/mol
C)300.06 g/mol
D)488.91 g/mol
E)492.37 g/mol

Question 35

What is the mass of 3.01 mol of sulfur atoms?

A)1.81 × 10²⁴ g
B)32.06 g
C)3.01 g
D)0.150 g
E)96.5 g

Question 36

How is the reaction shown below best classified? 2NaCl(s) + F₂(g) → 2NaF(s) + Cl₂(g)

A)decomposition
B)combination
C)single-replacement
D)double-replacement
E)precipitation

Question 37

What is the mass of one mole of carbon atoms?

A)6.022 g
B)12.01 g
C)7.232 g
D)6.022 × 10²³ g
E)7.232 × 10²⁴ g

Question 38

Iron reacts with oxygen to form iron(III) oxide according to the chemical equation below.What is the theoretical yield of product when 5.00 grams of Fe react with excess O₂? [Molar masses: Fe, 55.85 g/mol; O, 16.00g/mol] 4Fe(s) + 3O₂(g) → 2Fe₂O₃(s)

A)13.1 g
B)6.53 g
C)7.15 g
D)2.50 g
E)70.5 g

Question 39

The average mass of one atom of copper is 63.55 amu.What is the mass of Avogadro's number of copper atoms?

A)3.827 × 10²⁵ amu
B)63.55 g
C)3.827 × 10²⁵ g
D)63.55 atoms
E)63.55 formula units

Question 40

Lithium oxide can be produced by the reaction shown below.If a manufacturing company wants to make 25.0 g of Li₂O, what mass of Li is necessary? [Molar masses: Li, 6.94 g/mol; O, 16.00 g/mol] 4Li(s) + O₂(g) → 2Li₂O(s)

A)0.0861 g Li
B)2.903 g Li
C)11.6 g Li
D)12.5 g Li
E)23.2 g Li

Question 41

Aspirin is the common name for acetyl salicylic acid, C₉H₈O₄.One tablet contains 0.325 g of aspirin.How many moles of aspirin is this?

A)1.80 × 10^-6 mol
B)1.80 × 10^-3 mol
C)0.554 mol
D)554 mol
E)1.96 × 10²³ mol

Question 42

Classify the following reaction: Ce⁴⁺(aq) + Fe²⁺(aq) → Ce³⁺(aq) + Fe³⁺(aq)

A)precipitation
B)acid - base
C)oxidation - reduction
D)decomposition
E)combustion

Question 43

Methanol (CH₃OH) is the fuel used by racecars in the Indianapolis 500.It burns in the engine according to the equation below.How many moles of oxygen gas are necessary to react completely with 425 moles of methanol? 2CH₃OH(l) + 3O₂(g) → 2CO₂(g) + 4H₂O(g)

A)3 mol
B)255 mol
C)283 mol
D)638 mol
E)1275 mol

Question 44

The chemical equation below is not balanced.What is the coefficient of iron when the equation is balanced with smallest whole number coefficients? Fe(s) + O₂(g) → Fe₂O₃(s)

A)1
B)2
C)3
D)4
E)8

Question 45

How many moles of hydrogen gas are needed to react with oxygen to form one mole of water? 2H₂(g) + O₂(g) → 2H₂O(l)

A)0.5 mol
B)1 mol
C)2 mol
D)4 mol
E)6 mol

Question 46

Choose the best classification of the reaction represented by the following equation: C₆H₁₂O₆(s) + 6O₂(g) → 6CO₂(g) + 6H₂O(l)

A)combustion
B)acid-base
C)precipitation
D)decomposition
E)combination

Question 47

Which of the choices is the correctly balanced form of the following equation? C₆H₁₄(l) + O₂(g) → CO₂(g) + H₂O(l)

A)C₆H₁₄(l) + 13O₂(g) → 6CO₂(g) + 7H₂O(l)
B)C₆H₁₄(l) + 19O(g) → 6CO₂(g) + 7H₂O(l)
C)C₆H₁₄(l) + 19O₂(g) → 6CO₂(g) + 7H₂O(l)
D)2C₆H₁₄(l) + 19O₂(g) → 12CO₂(g) + 14H₂O(l)
E)C₁₂H₂₈(l) + 38O(g) → 12CO₂(g) + 14H₂O(l)

Question 48

Methanol (CH₃OH) is the fuel used by racecars in the Indianapolis 500.It burns in the engine according to the equation below.How many moles of oxygen gas are necessary to react completely with 12.5 L of methanol? [Density: CH₃OH, 0.7910g/mL; Molar mass: CH₃OH, 32.05 g/mol] 2CH₃OH(l) + 3O₂(g) → 2CO₂(g) + 4H₂O(g)

A)0.462 mol
B)2.16 mol
C)463 mol
D)740 mol
E)1850 mol

Question 49

Prozac, a drug prescribed to treat depression, has the formula C₁₇H₁₈F₃NO.If a patient was administered 15.0 mg of Prozac, how many moles of Prozac did he receive? [Molar mass: Prozac, 309.36 g/mol]

A)4.85 × 10⁻⁵ mol
B)48.5 mol
C)20.6 mol
D)4640 mol
E)2.92 × 10¹⁹ mol

Question 50

Consider the hypothetical reaction: 3A₂ + 2B → C + 2D If 6.0 moles of A are mixed with 2.0 moles of B, what is the maximum amount of C that can be formed?

A)1.0 mol
B)2.0 mol
C)5.0 mol
D)6.0 mol
E)8.0 mol

Question 51

Consider the following precipitation reaction.Which of the following correctly identifies the spectator ions in this reaction? Na₂S(aq) + CuSO₄(aq) → Na₂SO₄(aq) + CuS(s)

A)Na²⁺, S^2-, Cu²⁺, and SO₄2-
B)Na⁺, S^2-, Cu²⁺, and SO₄2-
C)Na⁺ and SO₄2-
D)Cu²⁺ and S^2-
E)There are no spectator ions present.

Question 52

What is the formula mass of carbon dioxide? [Atomic masses: C, 12.01 amu; O, 16.00 amu]

A)28.01 amu
B)28.01 g
C)44.01 amu
D)44.01 g
E)44.01 mol

Question 53

Choose the best classification of the reaction represented by the following equation: Na₂SO₄(aq) + Ba(OH)₂(aq) → BaSO₄(s) + 2NaOH(aq)

A)decomposition
B)combination
C)single-replacement
D)double-replacement
E)None of the choices are correct.

Question 54

Choose the best classification of the reaction represented by the following equation: 2KClO₃(s) → 2KCl(s) + 3O₂(g)

A)decomposition
B)combination
C)single-replacement
D)double-replacement
E)None of the choices are correct.

Question 55

Classify the following reaction: H₂SO₄(aq) + 2KOH(aq) → K₂SO₄(aq) + 2H₂O(aq)

A)precipitation
B)acid - base
C)oxidation - reduction
D)decomposition
E)combustion

Question 56

Incomplete combustion occurs when there is insufficient oxygen to react with a compound.The suffocating gas carbon monoxide is a product of incomplete combustion.How many moles of oxygen gas are required for the complete combustion of 11.0 moles of C₆H₁₄, a component of gasoline? C₆H₁₄(l) + 19O₂(g) → 12CO₂(g) + 14H₂O(l)

A)1.16 mol O₂
B)28.0 mol O₂
C)105 mol O₂
D)209 mol O₂
E)418 mol O₂

Question 57

When solutions of sodium sulfide and copper(II) sulfate are mixed, a precipitate of copper(II) sulfide is formed.What is the net ionic equation for this reaction?

A)Na₂S(aq) + CuSO₄(aq) → Na₂SO₄(aq) + CuS(s)
B)Na₂S(aq) + CuSO₄(aq) → CuS(s)
C)Cu²⁺(aq) + S^2-(aq) → Cu(s) + S(s)
D)Cu²⁺(aq) + S^2-(aq) → CuS(s)
E)2Na⁺(aq) + S^2-(aq) + Cu²⁺(aq) + SO₄^2-(aq) → 2Na⁺(aq) + SO₄^2-(aq)

Question 58

How many molecules are present in a 0.0200 mol sample of nicotine?

A)0.0400 molecules
B)1.20 × 10²² molecules
C)2.41 × 10²² molecules
D)6.02 × 10²³ molecules
E)1.20 × 10²³ molecules

Question 59

What is the mass of a 0.0200 mol sample of nicotine? [Formula mass: nicotine, 162.2 amu]

A)1.23 × 10^-4 g
B)0.308 g
C)3.24 g
D)32.4 g
E)8.11 × 10³ g

Question 60

How many aspirin molecules are present in a 0.325 g sample of aspirin? [Molar mass: aspirin, 180.2 g/mol]

A)1.09 × 10²¹ molecules
B)1.80 × 10⁻³ molecules
C)1.96 × 10²³ molecules
D)3.91 × 10²³ molecules
E)58.57 molecules

Question 61

Calculate the number of moles of BaF₂ in a 10.0 g sample of BaF₂.

A)9.77 mol
B)0.115 mol
C)17.4 mol
D)0.0631 mol
E)0.0570 mol

Question 62

One mole of iron contains 6.022 × 10²³ grams of Fe.

Question 63

Choose the best classification of the reaction represented by the following equation: HBr(aq) + KOH(aq) → KBr(aq) + H₂O(l)

A)combustion
B)combination
C)precipitation
D)decomposition
E)acid-base

Question 64

What is the mass of 4.35 moles of aluminum?

A)0.163 g
B)117 g
C)2.62 × 10²⁴ g
D)9.78 × 10²² g
E)27.8 g

Question 65

Choose the best classification of the reaction represented by the following equation: BaCl₂(aq) + K₂SO₄(aq) → BaSO₄(s) + 2KCl(aq)

A)single-replacement
B)double-replacement
C)combination
D)decomposition
E)oxidation-reduction

Question 66

Select the ionic compound that is insoluble in water.

A)Na₂CO₃
B)Fe(NO₃)₃
C)KBr
D)MgS
E)NH₄Br

Question 67

Which statement correctly describes what is happening in the reaction shown below? 2Mg(s) + S₂(g) → MgS(s)

A)Mg is oxidized.
B)S₂ loses electrons.
C)MgS is the reducing agent.
D)Mg is the oxidizing agent.
E)MgS gains electrons.

Question 68

One gram of gold (atomic mass 197 amu) contains more atoms than one gram of copper (atomic mass 63.55 amu).

Question 69

Choose the best classification of the reaction represented by the following equation: 2Fe³⁺(aq) + Fe(s) → 3Fe²⁺(aq)

A)combustion
B)decomposition
C)acid-base
D)oxidation-reduction
E)precipitation

Question 70

Choose the best classification of the reaction represented by the following equation: Pb(NO₃)₂(aq) + CaCl₂(aq) → PbCl₂(s) + Ca(NO₃)₂(aq)

A)combustion
B)acid-base
C)decomposition
D)precipitation
E)oxidation-reduction

Question 71

What is the mass of 3.5 × 10²² molecules of CO₂?

A)5.9 × 10^-2 g
B)2.6 g
C)1.8 × 10²⁴ g
D)1.5 × 10^-3 g
E)3.9 g

Question 72

During an oxidation-reduction reaction, the oxidizing agent loses electrons.

Question 73

The term "molecular mass" is appropriately used for covalent compounds, but not ionic compounds.

Question 74

In an acid-base reaction, what is transferred from the acid to the base?

A)an electron
B)a hydrogen cation, H⁺
C)an oxidizing agent
D)an oxygen atom
E)an OH^- ion

Question 75

The conversion of Fe²⁺ to Fe³⁺ is an oxidation reaction.

Question 76

In electrolysis, electrical energy is used to drive a non-spontaneous oxidation-reduction reaction to occur.

Question 77

One atomic mass unit is the same as one gram.

Question 78

Choose the best classification of the reaction represented by the following equation: MgO(s) + CO₂(g) → MgCO₃(s)

A)single-replacement
B)double-replacement
C)combination
D)decomposition
E)precipitation

Question 79

The formula mass of a compound is calculated by adding together the number of atoms that make up the compound.

Question 80

What is the precipitate that forms when solutions of Na₃PO₄ and Fe(NO₂)₃ are mixed?

A)NaNO₃
B)NaFe
C)FePO₄
D)PO₄NO₃
E)Fe₃PO₄