Question 1

When the hydrocarbon, C₈H₁₆, undergoes complete combustion, which is an oxidation-reduction reaction, a specific set of products is formed. If you write the equation for the reaction and balance it, the sum of the coefficients for the reagents in the balanced equation will be: Hint: Complete combustion of a hydrocarbon in oxygen always yields carbon dioxide and water vapor.

Accepted Answer

The answer of When the hydrocarbon, C₈H₁₆, undergoes complete combustion,...

Question 2

When the carbohydrate, C₁₂H₂₂O₁₁, undergoes complete combustion, which is an oxidation-reduction reaction, a specific set of products are formed. If you write the equation for the reaction and balance it, the sum of the coefficients for the reagents in the balanced equation will be: Hint: Complete combustion of a hydrocarbon in oxygen always yields carbon dioxide and water vapor.

Accepted Answer

The balanced equation for the complete combustion of C₁₂H₂₂O₁₁ is: C₁₂H₂₂O₁₁ + 12O₂ → 12CO₂ + 11H₂O. The sum of the coefficients for the reactants (1 for C₁₂H₂₂O₁₁ and 12 for O₂) is 1 + 12 = 13. The sum of the coefficients for the products (12 for CO₂ and 11 for H₂O) is 12 + 11 = 23. The total sum of coefficients is 13 + 23 = 36.

Question 3

When the carbohydrate, C₁₂H₂₂O₁₁, undergoes complete combustion, the reducing agent in the reaction is

Accepted Answer

The carbohydrate (C12H22O11) acts as the reducing agent because it donates electrons to oxygen during the combustion process, resulting in the formation of carbon dioxide and water.

Question 4

When glucose, C₆H₁₂O₆, undergoes complete combustion, the species that is reduced is

Accepted Answer

In the combustion of glucose, oxygen (O2) is reduced to form water (H2O).

Question 5

What is the equation that best describes the oxidation of iron by oxygen in the presence of moisture? Hint: Be sure to consider the oxidation numbers when determining the equation.

Accepted Answer

The equation C represents the formation of rust, which is hydrated iron(III) oxide, from iron, oxygen, and water.

Question 6

When hydrocarbons or coal contain sulfur what is formed during the complete combustion? Hint: Consider the products of a complete combustion reaction with something containing sulfur. What should always be produced?

Accepted Answer

During the complete combustion of sulfur-containing hydrocarbons or coal, sulfur dioxide (SO₂) is formed as sulfur reacts with oxygen.

Question 7

The oxidation of aluminum occurs slowly, due to the formation of which substance on the surface of the metal? Hint: Consider the reaction of aluminum and oxygen.

Accepted Answer

Aluminum reacts with oxygen to form aluminum oxide (Al₂O₃), which creates a protective layer on the surface, slowing further oxidation.

Question 8

When aluminum is exposed to the environment it does not corrode in the same way as iron. Which of the following best explains why? Hint: Look at the chemical properties of iron and aluminum.

Accepted Answer

Aluminum forms a thin layer of aluminum oxide when it oxidizes, which acts as a protective barrier preventing further corrosion.

Question 9

The amount of iron in a sample can be determined by a titration using dichromate ion, Cr₂O₇^2-, in acidic solution. The iron is first converted to Fe²⁺, which is then titrated by the dichromate ion. The reaction is: 6 Fe²⁺(aq)+ Cr₂O₇^2-(aq)+ 14 H⁺ $\rarr$ 6 Fe³⁺(aq)+ 2 Cr³⁺(aq)+ 7 H₂O How many grams of iron are present in a sample if it required 42.7 mL of 0.0180 M Na₂Cr₂O₇(aq)solution for the titration described by the redox equation above?

Accepted Answer

First, calculate moles of dichromate: 0.0427 L * 0.0180 mol/L = 0.0007686 mol. From the balanced equation, 1 mol of Cr2O7^2- reacts with 6 mol of Fe^2+. Therefore, moles of Fe^2+ = 0.0007686 mol * 6 = 0.0046116 mol. The molar mass of Fe is 55.85 g/mol, so mass of Fe = 0.0046116 mol * 55.85 g/mol = 0.2576 g, which rounds to 0.258 g.

Question 10

The strength of a hydrogen peroxide, H₂O₂, solution can be determined by titration with permanganate solution. The reaction is: 2 MnO₄^-(aq)+ 5 H₂O₂(aq)+ 6 H⁺$\rarr$ 5O₂(g)+ 2 Mn²⁺(aq)+ 8 H₂O If it required 80.0 mL of 0.0220 molar MnO₄^-(aq)solution to titrate 5.0 mL of a H₂O₂(aq)solution, what is the molarity of the H₂O₂(aq)solution?

Accepted Answer

The answer of The strength of a hydrogen peroxide, H₂O₂,...

Question 11

Zinc reacts with the permanganate ion to form Zn²⁺(aq)ions and Mn²⁺(aq)ions. The reaction is:5 Zn(s)+ 2 MnO₄^-(aq)+ 16 H⁺ $\rarr$ 5 Zn²⁺(aq)+ 2 Mn²⁺(aq)+ 8 H₂O How many grams of zinc are required to completely react with 100.0 mL of a 0.0150 M solution of KMnO₄(aq)?

Accepted Answer

The answer of Zinc reacts with the permanganate ion to...

Question 12

SO₂ is a dangerous air pollutant, which can harm human lungs. The quantity of SO₂ in air can be determined by the reaction, 2 MnO₄^-(aq)+ 5 SO₂(g)+ 2 H₂O $\rarr$ 5 SO₄^2-(aq)+ 2 Mn²⁺(aq)+ 4 H⁺ It required 185 mL of 0.0200 M MnO₄^-(aq)solution to completely react with all of the SO₂ in a sample of air. How many grams of SO₂ were in the sample?

Accepted Answer

The answer of SO₂ is a dangerous air pollutant, which...

Question 13

You can dissolve a penny using nitric acid, HNO₃. The reaction Cu(s)+ 4 HNO₃(aq)$\rarr$Cu(NO₃)₂(aq)+ 2 NO₂(g)+ 2 H₂O(l)is used to dissolve copper metal. If there is 1.000 g of copper to be dissolved, and instructions say to use four times as much acid as the required amount, how many mL (to the nearest mL)of 15.0 M nitric acid would be required to dissolve the copper? Hint: Don't forget the coefficients in the balanced reaction above when performing your calculations with nitric acid.

Accepted Answer

The balanced reaction shows that 1 mole of Cu reacts with 4 moles of HNO3. The molar mass of Cu is 63.55 g/mol, so 1.000 g of Cu is 1.000 g / 63.55 g/mol = 0.01575 mol of Cu. To dissolve this amount of Cu, we need 4 times as much HNO3, or 4 x 0.01575 mol = 0.063 mol of HNO3. The molarity of the HNO3 solution is 15.0 M, so we need 0.063 mol / 15.0 M = 0.0042 L = 4.2 mL of HNO3. To the nearest mL, this is 5 mL.

Question 14

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

The answer of Fe²⁺(aq)reacts with MnO₄^-(aq)ion in acidic solution to...

Question 15

Fe²⁺(aq)reacts with MnO₄^-(aq)ion in acidic solution to yield Fe³⁺(aq)ions and Mn²⁺(aq)ions. 5Fe²⁺(aq)+ MnO₄^-(aq)+ 8H⁺ $\rarr$ 5Fe³⁺(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 56.15 mL of 0.01301 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

The correct answer is A.The balanced chemical equation is:5Fe2+(aq) + MnO4-(aq) + 8H+(aq) → 5Fe3+(aq) + Mn2+(aq) + 4H2OThe molarity of the permanganate solution is 0.01301 M.The volume of the permanganate solution used is 56.15 mL, which is 0.05615 L.The number of moles of permanganate used is:0.01301 M × 0.05615 L = 0.000730 molThe number of moles of Fe2+ in the sample is:0.000730 mol × 5 = 0.00365 molThe mass of Fe2+ in the sample is:0.00365 mol × 55.845 g/mol = 0.203 gThe mass of the sample is:0.203 g / 0.558 = 0.364 gTherefore, the sample weighs 0.364 g, if it was in fact pure melanterite.

Question 16

What is the compound formed in the reaction between hydrogen sulfide and silver metal, which is responsible for the dull film on the silver metal when it tarnishes in air?

Accepted Answer

The compound formed is silver sulfide (Ag2S), which is responsible for the tarnishing of silver when it reacts with hydrogen sulfide in the air.

Question 17

Which metal(s)can be used to reduce compounds of silver to silver metal?

Accepted Answer

Aluminum (Al) is more reactive than silver and can reduce silver compounds to silver metal.

Question 18

Which is the most likely reaction to reduce silver ions to silver metal? Hint: Silver metal refers to silver (Ag)in the solid phase.

Accepted Answer

The answer of Which is the most likely reaction to...

Question 19

The oxidation number of N in HNO₃ is

Accepted Answer

The answer of The oxidation number of N in HNO₃...

Question 20

The oxidation number of V in VOCl₃ is ________.

Accepted Answer

The answer of The oxidation number of V in VOCl₃...

Quiz 6: Oxidation-Reduction Reactions

When the carbohydrate, C₁₂H₂₂O₁₁, undergoes complete combustion, the reducing agent in the reaction is

When glucose, C₆H₁₂O₆, undergoes complete combustion, the species that is reduced is

What is the equation that best describes the oxidation of iron by oxygen in the presence of moisture? Hint: Be sure to consider the oxidation numbers when determining the equation.

When hydrocarbons or coal contain sulfur what is formed during the complete combustion? Hint: Consider the products of a complete combustion reaction with something containing sulfur. What should always be produced?

The oxidation of aluminum occurs slowly, due to the formation of which substance on the surface of the metal? Hint: Consider the reaction of aluminum and oxygen.

When aluminum is exposed to the environment it does not corrode in the same way as iron. Which of the following best explains why? Hint: Look at the chemical properties of iron and aluminum.

Zinc reacts with the permanganate ion to form Zn²⁺(aq) ions and Mn²⁺(aq) ions. The reaction is:5 Zn(s) + 2 MnO₄^-(aq) + 16 H⁺ $\rarr$ 5 Zn²⁺(aq) + 2 Mn²⁺(aq) + 8 H₂O How many grams of zinc are required to completely react with 100.0 mL of a 0.0150 M solution of KMnO₄(aq) ?

What is the compound formed in the reaction between hydrogen sulfide and silver metal, which is responsible for the dull film on the silver metal when it tarnishes in air?

Which metal(s) can be used to reduce compounds of silver to silver metal?

Which is the most likely reaction to reduce silver ions to silver metal? Hint: Silver metal refers to silver (Ag) in the solid phase.

The oxidation number of N in HNO₃ is

The oxidation number of V in VOCl₃ is ________.

Quiz 6: Oxidation-Reduction Reactions

When the carbohydrate, C12H22O11, undergoes complete combustion, the reducing agent in the reaction is

When glucose, C6H12O6, undergoes complete combustion, the species that is reduced is

What is the equation that best describes the oxidation of iron by oxygen in the presence of moisture? Hint: Be sure to consider the oxidation numbers when determining the equation.

When hydrocarbons or coal contain sulfur what is formed during the complete combustion? Hint: Consider the products of a complete combustion reaction with something containing sulfur. What should always be produced?

The oxidation of aluminum occurs slowly, due to the formation of which substance on the surface of the metal? Hint: Consider the reaction of aluminum and oxygen.

When aluminum is exposed to the environment it does not corrode in the same way as iron. Which of the following best explains why? Hint: Look at the chemical properties of iron and aluminum.

Zinc reacts with the permanganate ion to form Zn2+(aq) ions and Mn2+(aq) ions. The reaction is:5 Zn(s) + 2 MnO4-(aq) + 16 H+ →\rarr→ 5 Zn2+(aq) + 2 Mn2+(aq) + 8 H2O How many grams of zinc are required to completely react with 100.0 mL of a 0.0150 M solution of KMnO4(aq) ?

What is the compound formed in the reaction between hydrogen sulfide and silver metal, which is responsible for the dull film on the silver metal when it tarnishes in air?

Which metal(s) can be used to reduce compounds of silver to silver metal?

Which is the most likely reaction to reduce silver ions to silver metal? Hint: Silver metal refers to silver (Ag) in the solid phase.

The oxidation number of N in HNO3 is

The oxidation number of V in VOCl3 is ________.

When the carbohydrate, C₁₂H₂₂O₁₁, undergoes complete combustion, the reducing agent in the reaction is

When glucose, C₆H₁₂O₆, undergoes complete combustion, the species that is reduced is

Zinc reacts with the permanganate ion to form Zn²⁺(aq) ions and Mn²⁺(aq) ions. The reaction is:5 Zn(s) + 2 MnO₄^-(aq) + 16 H⁺ $\rarr$ 5 Zn²⁺(aq) + 2 Mn²⁺(aq) + 8 H₂O How many grams of zinc are required to completely react with 100.0 mL of a 0.0150 M solution of KMnO₄(aq) ?

The oxidation number of N in HNO₃ is

The oxidation number of V in VOCl₃ is ________.