Question 1

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

Accepted Answer

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

Question 2

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]

Accepted Answer

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

Question 3

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

Accepted Answer

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

Question 4

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

Accepted Answer

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

Question 5

One mole of H2O contains a total of 6.022 × 1023 atoms.

Accepted Answer

A) True 
 B)False

Question 6

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?

Accepted Answer

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) 
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 7

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

Accepted Answer

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

Question 8

In a properly balanced equation, the number of moles of reactants and the number of moles of products may differ.

Accepted Answer

A) True 
 B)False

Question 9

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

Accepted Answer

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

Question 10

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)

Accepted Answer

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

Question 11

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

Accepted Answer

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

Question 12

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

Accepted Answer

A) Mg is oxidized. 
B) S2 loses electrons. 
C) MgS is the reducing agent. 
D) Mg is the oxidizing agent. 
E) MgS gains electrons. 
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 13

One atomic mass unit is the same as one gram.

Accepted Answer

A) True 
 B)False

Question 14

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

Accepted Answer

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

Question 15

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)

Accepted Answer

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 
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 16

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

Accepted Answer

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

Question 17

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

Accepted Answer

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

Question 18

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)

Accepted Answer

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

Question 19

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

Accepted Answer

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

Question 20

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

Accepted Answer

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

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

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

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

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

One mole of H2O contains a total of 6.022 × 1023 atoms.

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?

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

In a properly balanced equation, the number of moles of reactants and the number of moles of products may differ.

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

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)

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

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

One atomic mass unit is the same as one gram.

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

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)

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

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

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)

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

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

Chemistry:methods and Measurement

The Structure of the Atom and the Periodic Table

Structure and Properties of Ionic and Covalent Compounds

States of Matter- Gases, Liquids, and Solids

Solutions

Energy, Rate and Equilibrium

Acids and Bases

The Nucleus, Radioactivity, and Nuclear Medicine

An Introduction to Organic Chemistry- the Saturated Hydrocarbons

The Unsaturated Hydrocarbons- Alkenes, Alkynes, and Aromatics

Alcohols, Phenols, Thiols, and Ethers

Aldehydes and Ketones

Carboxylic Acids and Carboxylic Acid Derivatives

Amines and Amides

Carbohydrates

Lipids and Their Functions in Biochemical Systems

Protein Structure and Function

Enzymes

Introduction to Molecular Genetics

Carbohydrate Metabolism

Aerobic Respiration and Energy Production

Fatty Acid Metabolism

Filters

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

One mole of H₂O contains a total of 6.022 × 10²³ atoms.

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

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

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)

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

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

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

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)

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)

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