Question 1

The oxidation number of P in HPO42- is ________.

Accepted Answer

+5

Question 2

Coal is still a large part of the world's energy supply, but not all coal is the same. Some coal deposits contain high amounts of sulfur. Explain how burning coal with high sulfur content, in form of SO2,could be harmful to the environment.

Accepted Answer

The sulfur in the coal will form SO₂, which can further be oxidized to SO₃. In the atmosphere, SO₃ reacts with water to form H₂SO₄ which leads to acid rain. Acid rain has many harmful effects on the environment.

Question 3

What is the change in the oxidation number of carbon in the following? K2C2O4 $\rarr$ K2CO3

Accepted Answer

A) decrease by one unit 
B) decrease by two units 
C) decrease by three units 
D) increase by one unit 
E) increase by two units 
A) decrease by one unit 
B) decrease by two units 
C) decrease by three units 
D) increase by one unit 
E) increase by two units D

Question 4

What is the change in the oxidation number of sulfur in the following?
 K2SO3 $\rarr$ K2SO4

Accepted Answer

A) decrease by three units 
B) decrease by four units 
C) increase by two units 
D) increase by three units 
E) increase by four units 
A) decrease by three units 
B) decrease by four units 
C) increase by two units 
D) increase by three units 
E) increase by four units

Question 5

When concentrated nitric acid behaves as an oxidizing agent, how does the oxidation number of N change? Hint: An oxidizing agent is reduced.

Accepted Answer

The answer of When concentrated nitric acid behaves as an...

Question 6

Nitric acid reacts with copper metal according to the unbalanced equation,
 Cu(s)+ HNO3(aq)$\rarr$Cu(NO3)2(aq)+ NO2(g)+ H2O Which is correct?

Accepted Answer

A) The nitrate ion is the reducing agent, and it is reduced to water. 
B) The product of the reduction reaction is NO2. 
C) The product of the reduction reaction is Cu(NO3)2. 
D) Copper is the oxidizing agent, and it is reduced to Cu(NO3)2. 
E) Both water and copper are reduced. 
A) The nitrate ion is the reducing agent, and it is reduced to water. 
B) The product of the reduction reaction is NO2. 
C) The product of the reduction reaction is Cu(NO3)2. 
D) Copper is the oxidizing agent, and it is reduced to Cu(NO3)2. 
E) Both water and copper are reduced.

Question 7

The activity series of metals is Au < Ag < Cu < Sn < Cd < Zn < Al < Mg < Na < Cs Which reaction below occurs spontaneously upon mixing the reagents shown?

Accepted Answer

A) Ag(s)+ Zn2+(aq)$\rarr$ Ag+(aq)+ Zn(s) 
B) Ag(s)+ Cd2+(aq)$\rarr$ Ag+(aq)+ Cd(s) 
C) Zn(s)+ Mg2+(aq)$\rarr$ Zn2+(aq)+ Mg(s) 
D) Ag(s)+ Mg2+(aq)$\rarr$ Ag+(aq)+ Mg(s) 
E) Sn(s)+ Cu2+(aq)$\rarr$ Sn2+(aq)+ Cu(s) 
A) Ag(s)+ Zn2+(aq)$\rarr$ Ag+(aq)+ Zn(s) 
B) Ag(s)+ Cd2+(aq)$\rarr$ Ag+(aq)+ Cd(s) 
C) Zn(s)+ Mg2+(aq)$\rarr$ Zn2+(aq)+ Mg(s) 
D) Ag(s)+ Mg2+(aq)$\rarr$ Ag+(aq)+ Mg(s) 
E) Sn(s)+ Cu2+(aq)$\rarr$ Sn2+(aq)+ Cu(s)

Question 8

After balancing the following equation for the reaction in acidic media, 
H+ + HSO3-(aq)+ MnO4-(aq)$\rarr$ MnO2(s)+ HSO4-(aq)+ H2O what is the sum of ALL the coefficients in the equation? (Remember to include values of 1 in your summation.)Hint: Start by balancing each half-reaction.

Accepted Answer

A) 7 
B) 9 
C) 13 
D) 15 
E) 19 
A) 7 
B) 9 
C) 13 
D) 15 
E) 19

Question 9

Consider the oxidation states of hydrogen in the following compounds: LiH, NaH, KH, MgH2, CaH2, NiH, CuH, ZnH2, HF, HCl, HBr, HI, H2O, H2S, H2Se, and H2Te. What statement is true?

Accepted Answer

A) All of the metal compounds have H in the oxidation state of -1, while the nonmetal compounds have H in the oxidation state of +1. 
B) In general, metals form covalent compounds with hydrogen, whereas, nonmetals form molecular compounds with hydrogen. 
C) In general, metals form molecular compounds with hydrogen, whereas, nonmetals form ionic compounds with hydrogen. 
D) All of the metal compounds have H in the oxidation state of +1, while the nonmetal compounds have H in the oxidation state of -1. 
E) Hydrogen can only react with nonmetallic elements. 
A) All of the metal compounds have H in the oxidation state of -1, while the nonmetal compounds have H in the oxidation state of +1. 
B) In general, metals form covalent compounds with hydrogen, whereas, nonmetals form molecular compounds with hydrogen. 
C) In general, metals form molecular compounds with hydrogen, whereas, nonmetals form ionic compounds with hydrogen. 
D) All of the metal compounds have H in the oxidation state of +1, while the nonmetal compounds have H in the oxidation state of -1. 
E) Hydrogen can only react with nonmetallic elements.

Question 10

Ethanol, C2H5OH, is often found in gasoline. In these cases it is often produced from ethanol plants that turn corn into ethanol. The cost-benefit analysis of this process is often a topic of debate. Explain why some ethanol in gasoline could aid in the efficiency of your engine.

Accepted Answer

Ethanol contains oxygen and th

Question 11

Consider the redox equation, 
2VO43-(aq)+ SO2(g)+ 8H+(aq)$\rarr$ 2VO2+(aq)+ SO42-(aq)+ 4H2O(l) The oxidizing agent is

Accepted Answer

A) VO43-(aq) 
B) VO2+(aq) 
C) H+(aq) 
D) SO2(g) 
E) SO42-(aq) 
A) VO43-(aq) 
B) VO2+(aq) 
C) H+(aq) 
D) SO2(g) 
E) SO42-(aq)

Question 12

Magnesium metal reacts with aqueous sulfuric acid solution to produce aqueous magnesium sulfate and hydrogen gas. In the course of the reaction, which element undergoes an increase in oxidation number?

Accepted Answer

A) hydrogen 
B) magnesium 
C) oxygen 
D) sulfur 
E) both magnesium and hydrogen 
A) hydrogen 
B) magnesium 
C) oxygen 
D) sulfur 
E) both magnesium and hydrogen

Question 13

The activity series of metals is Au < Ag < Cu < Sn < Cd < Zn < Al < Mg < Na < Cs Which reaction below does not occur spontaneously upon mixing the reagents shown?

Accepted Answer

A) Al(s)+ Cd2+(aq)$\rarr$ Al3+(aq)+ Cd(s) 
B) Mg(s)+ Cu2+(aq)$\rarr$ Mg2+(aq)+ Cu(s) 
C) Zn(s)+ Ag+(aq)$\rarr$Zn2+(aq)+ Ag(s) 
D) Zn(s)+ Al3+(aq)$\rarr$Zn2+(aq)+ Al(s) 
E) Na(s)+ Au3+(aq)$\rarr$Na+(aq)+ Au(s) 
A) Al(s)+ Cd2+(aq)$\rarr$ Al3+(aq)+ Cd(s) 
B) Mg(s)+ Cu2+(aq)$\rarr$ Mg2+(aq)+ Cu(s) 
C) Zn(s)+ Ag+(aq)$\rarr$Zn2+(aq)+ Ag(s) 
D) Zn(s)+ Al3+(aq)$\rarr$Zn2+(aq)+ Al(s) 
E) Na(s)+ Au3+(aq)$\rarr$Na+(aq)+ Au(s)

Question 14

The reaction, Cl2(g)+ NaBr(aq)$\rarr$NaCl(aq)+ Br2(l), involves changes in oxidation number and is therefore classified as a redox reaction.

Accepted Answer

A) True 
 B)False

Question 15

It is proposed to measure the CO gas present in air samples by passing the gas through a solution of potassium permanganate. The reaction that occurs is,   In a trial run, it required 102 liters of air containing CO (no other substances that would react with permanganate were present)to completely decolorize 250 mL of 0.0150 M MnO4-(aq)solution in a scrubber. If air weighs 1.29 g/liter, what is the percent by weight of CO in the air? Hint: Make sure your equation is balanced and pay attention to your units throughout the problem.

Accepted Answer

Question 16

What is the oxidation number of sulfur in Rb2S2O4?

Accepted Answer

A) -2 
B) +1 
C) +3 
D) +5 
E) +6 
A) -2 
B) +1 
C) +3 
D) +5 
E) +6

Question 17

In a chemical reaction, one of the reactants is MnO2. It is transformed into MnSO4. What is the change in the oxidation number of the manganese?

Accepted Answer

A) There is no change in oxidation number. 
B) The oxidation number increases by one unit. 
C) The oxidation number increases by two units. 
D) The oxidation number decreases by one unit. 
E) The oxidation number decreases by two units. 
A) There is no change in oxidation number. 
B) The oxidation number increases by one unit. 
C) The oxidation number increases by two units. 
D) The oxidation number decreases by one unit. 
E) The oxidation number decreases by two units.

Question 18

After balancing the following equation for the reaction in acidic media, 
Fe2+(aq)+ Cr2O72(aq)+ H+(aq)$\rarr$ Cr3+(aq)+ Fe3+(aq)+ H2O(l)what is the sum of ALL the coefficients in the equation?(Remember to include values of 1 in your summation.)Hint: Start by balancing each half-reaction.

Accepted Answer

A) 6 
B) 22 
C) 30 
D) 32 
E) 36 
A) 6 
B) 22 
C) 30 
D) 32 
E) 36

Question 19

Fe2+(aq)reacts with MnO4-(aq)ion in acidic solution to yield Fe3+(aq)ions and Mn2+(aq)ions.5Fe2+(aq)+ MnO4-(aq)+ 8H+ $\rarr$ 5 Fe3+(aq)+ Mn2+(aq)+ 4H2O Melanterite is a greenish mineral, and can be found on the walls of mines. A sample of melanterite, FeSO4·7H2O, was analyzed for purity using this reaction by titration of an aqueous solution of the sample. One such sample required 47.35 mL of 0.0175350 M permanganate solution to completely titrate all the iron in the sample by the reaction shown above. How much did the sample weigh, if it was in fact pure melanterite? Hint: Watch your units carefully at each step of the problem.

Accepted Answer

A) 0.596 g 
B) 0.184 g 
C) 0.461 g 
D) 1.154 g 
E) 4.87 g 
A) 0.596 g 
B) 0.184 g 
C) 0.461 g 
D) 1.154 g 
E) 4.87 g

Question 20

Balance the redox reaction below in basic solution.Cl2(g)→ Cl-(aq)+ ClO-(aq)What is the coefficient of OH- in the final balanced equation? Hint: Consider your oxidation numbers when balancing redox reactions.

Accepted Answer

The oxidation number of P in HPO₄^2- is ________.

Coal is still a large part of the world's energy supply, but not all coal is the same. Some coal deposits contain high amounts of sulfur. Explain how burning coal with high sulfur content, in form of SO₂,could be harmful to the environment.

What is the change in the oxidation number of carbon in the following? K₂C₂O₄ $\rarr$ K₂CO₃

What is the change in the oxidation number of sulfur in the following? K₂SO₃ $\rarr$ K₂SO₄

When concentrated nitric acid behaves as an oxidizing agent, how does the oxidation number of N change? Hint: An oxidizing agent is reduced.

Nitric acid reacts with copper metal according to the unbalanced equation, Cu(s)+ HNO₃(aq) $\rarr$ Cu(NO₃)₂(aq)+ NO₂(g)+ H₂O Which is correct?

The activity series of metals is Au < Ag < Cu < Sn < Cd < Zn < Al < Mg < Na < Cs Which reaction below occurs spontaneously upon mixing the reagents shown?

After balancing the following equation for the reaction in acidic media, H⁺ + HSO₃^-(aq)+ MnO₄^-(aq) $\rarr$ MnO₂(s)+ HSO₄^-(aq)+ H₂O what is the sum of ALL the coefficients in the equation? (Remember to include values of 1 in your summation.)Hint: Start by balancing each half-reaction.

Consider the oxidation states of hydrogen in the following compounds: LiH, NaH, KH, MgH₂, CaH₂, NiH, CuH, ZnH₂, HF, HCl, HBr, HI, H₂O, H₂S, H₂Se, and H₂Te. What statement is true?

Ethanol, C₂H₅OH, is often found in gasoline. In these cases it is often produced from ethanol plants that turn corn into ethanol. The cost-benefit analysis of this process is often a topic of debate. Explain why some ethanol in gasoline could aid in the efficiency of your engine.

Consider the redox equation, 2VO₄^3-(aq)+ SO₂(g)+ 8H⁺(aq) $\rarr$ 2VO²⁺(aq)+ SO₄^2-(aq)+ 4H₂O(l) The oxidizing agent is

Magnesium metal reacts with aqueous sulfuric acid solution to produce aqueous magnesium sulfate and hydrogen gas. In the course of the reaction, which element undergoes an increase in oxidation number?

The activity series of metals is Au < Ag < Cu < Sn < Cd < Zn < Al < Mg < Na < Cs Which reaction below does not occur spontaneously upon mixing the reagents shown?

The reaction, Cl₂(g)+ NaBr(aq) $\rarr$ NaCl(aq)+ Br₂(l), involves changes in oxidation number and is therefore classified as a redox reaction.

What is the oxidation number of sulfur in Rb₂S₂O₄?

In a chemical reaction, one of the reactants is MnO₂. It is transformed into MnSO₄. What is the change in the oxidation number of the manganese?

Balance the redox reaction below in basic solution.Cl₂(g)→ Cl^-(aq)+ ClO^-(aq)What is the coefficient of OH^- in the final balanced equation? Hint: Consider your oxidation numbers when balancing redox reactions.

A Very Brief History of Chemistry

Scientific Measurements

Elements, Compounds, and the Periodic Table

The Mole and Stoichiometry

Molecular View of Reactions in Aqueous Solutions

Energy and Chemical Change

The Quantum Mechanical Atom

The Basics of Chemical Bonding

Theories of Bonding and Structure

Properties of Gases

Intermolecular Attractions and the Properties of Liquids and Solids

Mixtures at the Molecular Level: Properties of Solutions

Chemical Kinetics

Chemical Equilibrium

Acids and Bases, a Molecular Look

Acid-Base Equilibria in Aqueous Solutions

Solubility and Simultaneous Equilibria

Thermodynamics

Electrochemistry

Nuclear Reactions and Their Role in Chemistry

Metal Complexes

Organic Compounds, Polymers, and Biochemicals

Filters

Exam 6: Oxidation-Reduction Reactions

The oxidation number of P in HPO42- is ________.

Coal is still a large part of the world's energy supply, but not all coal is the same. Some coal deposits contain high amounts of sulfur. Explain how burning coal with high sulfur content, in form of SO2,could be harmful to the environment.

What is the change in the oxidation number of carbon in the following? K2C2O4 →\rarr→ K2CO3

What is the change in the oxidation number of sulfur in the following? K2SO3 →\rarr→ K2SO4

When concentrated nitric acid behaves as an oxidizing agent, how does the oxidation number of N change? Hint: An oxidizing agent is reduced.

Nitric acid reacts with copper metal according to the unbalanced equation, Cu(s)+ HNO3(aq) →\rarr→ Cu(NO3)2(aq)+ NO2(g)+ H2O Which is correct?

The activity series of metals is Au < Ag < Cu < Sn < Cd < Zn < Al < Mg < Na < Cs Which reaction below occurs spontaneously upon mixing the reagents shown?

After balancing the following equation for the reaction in acidic media, H+ + HSO3-(aq)+ MnO4-(aq) →\rarr→ MnO2(s)+ HSO4-(aq)+ H2O what is the sum of ALL the coefficients in the equation? (Remember to include values of 1 in your summation.)Hint: Start by balancing each half-reaction.

Consider the oxidation states of hydrogen in the following compounds: LiH, NaH, KH, MgH2, CaH2, NiH, CuH, ZnH2, HF, HCl, HBr, HI, H2O, H2S, H2Se, and H2Te. What statement is true?

Ethanol, C2H5OH, is often found in gasoline. In these cases it is often produced from ethanol plants that turn corn into ethanol. The cost-benefit analysis of this process is often a topic of debate. Explain why some ethanol in gasoline could aid in the efficiency of your engine.

Consider the redox equation, 2VO43-(aq)+ SO2(g)+ 8H+(aq) →\rarr→ 2VO2+(aq)+ SO42-(aq)+ 4H2O(l) The oxidizing agent is

Magnesium metal reacts with aqueous sulfuric acid solution to produce aqueous magnesium sulfate and hydrogen gas. In the course of the reaction, which element undergoes an increase in oxidation number?

The activity series of metals is Au < Ag < Cu < Sn < Cd < Zn < Al < Mg < Na < Cs Which reaction below does not occur spontaneously upon mixing the reagents shown?

The reaction, Cl2(g)+ NaBr(aq) →\rarr→ NaCl(aq)+ Br2(l), involves changes in oxidation number and is therefore classified as a redox reaction.

What is the oxidation number of sulfur in Rb2S2O4?

In a chemical reaction, one of the reactants is MnO2. It is transformed into MnSO4. What is the change in the oxidation number of the manganese?

After balancing the following equation for the reaction in acidic media, Fe2+(aq)+ Cr2O72(aq)+ H+(aq) →\rarr→ Cr3+(aq)+ Fe3+(aq)+ H2O(l)what is the sum of ALL the coefficients in the equation?(Remember to include values of 1 in your summation.)Hint: Start by balancing each half-reaction.

Balance the redox reaction below in basic solution.Cl2(g)→ Cl-(aq)+ ClO-(aq)What is the coefficient of OH- in the final balanced equation? Hint: Consider your oxidation numbers when balancing redox reactions.

A Very Brief History of Chemistry

Scientific Measurements

Elements, Compounds, and the Periodic Table

The Mole and Stoichiometry

Molecular View of Reactions in Aqueous Solutions

Energy and Chemical Change

The Quantum Mechanical Atom

The Basics of Chemical Bonding

Theories of Bonding and Structure

Properties of Gases

Intermolecular Attractions and the Properties of Liquids and Solids

Mixtures at the Molecular Level: Properties of Solutions

Chemical Kinetics

Chemical Equilibrium

Acids and Bases, a Molecular Look

Acid-Base Equilibria in Aqueous Solutions

Solubility and Simultaneous Equilibria

Thermodynamics

Electrochemistry

Nuclear Reactions and Their Role in Chemistry

Metal Complexes

Organic Compounds, Polymers, and Biochemicals

Filters

The oxidation number of P in HPO₄^2- is ________.

Coal is still a large part of the world's energy supply, but not all coal is the same. Some coal deposits contain high amounts of sulfur. Explain how burning coal with high sulfur content, in form of SO₂,could be harmful to the environment.

What is the change in the oxidation number of carbon in the following? K₂C₂O₄ $\rarr$ K₂CO₃

What is the change in the oxidation number of sulfur in the following? K₂SO₃ $\rarr$ K₂SO₄

Nitric acid reacts with copper metal according to the unbalanced equation, Cu(s)+ HNO₃(aq) $\rarr$ Cu(NO₃)₂(aq)+ NO₂(g)+ H₂O Which is correct?

After balancing the following equation for the reaction in acidic media, H⁺ + HSO₃^-(aq)+ MnO₄^-(aq) $\rarr$ MnO₂(s)+ HSO₄^-(aq)+ H₂O what is the sum of ALL the coefficients in the equation? (Remember to include values of 1 in your summation.)Hint: Start by balancing each half-reaction.

Consider the oxidation states of hydrogen in the following compounds: LiH, NaH, KH, MgH₂, CaH₂, NiH, CuH, ZnH₂, HF, HCl, HBr, HI, H₂O, H₂S, H₂Se, and H₂Te. What statement is true?

Ethanol, C₂H₅OH, is often found in gasoline. In these cases it is often produced from ethanol plants that turn corn into ethanol. The cost-benefit analysis of this process is often a topic of debate. Explain why some ethanol in gasoline could aid in the efficiency of your engine.

Consider the redox equation, 2VO₄^3-(aq)+ SO₂(g)+ 8H⁺(aq) $\rarr$ 2VO²⁺(aq)+ SO₄^2-(aq)+ 4H₂O(l) The oxidizing agent is

The reaction, Cl₂(g)+ NaBr(aq) $\rarr$ NaCl(aq)+ Br₂(l), involves changes in oxidation number and is therefore classified as a redox reaction.

What is the oxidation number of sulfur in Rb₂S₂O₄?

In a chemical reaction, one of the reactants is MnO₂. It is transformed into MnSO₄. What is the change in the oxidation number of the manganese?

Balance the redox reaction below in basic solution.Cl₂(g)→ Cl^-(aq)+ ClO^-(aq)What is the coefficient of OH^- in the final balanced equation? Hint: Consider your oxidation numbers when balancing redox reactions.