Chemistry Chapter 08 Quiz

Questions and Answers

Classify the following changes in each unbalanced chemical equation as oxidation or reduction:

Ti→TiO2 = Oxidation C2H6→C2H2 = Oxidation Ca→Ca2++2e− = Oxidation SiO2→SiO = Reduction C4H8O→C4H10O = Reduction Cr6++3e−→Cr3+ = Reduction

Give one reason why it can be difficult to design a long-lived oxidation catalyst.

The organic part of the catalyst is a target for oxidation.

Is SO2−4 the oxidizing agent, the reducing agent, both, or neither?

Oxidizing agent

Both

Neither (correct)

Reducing agent

During charging, is Pb2+ being oxidized, reduced, both, or neither?

Both Signup and view all the answers

What substance is oxidized?

C8H7ON Signup and view all the answers

What is the oxidizing agent?

O2 Signup and view all the answers

Why are TNT explosions so powerful?

TNT decomposes rapidly into several gaseous products. Signup and view all the answers

How does an alkaline cell differ from a zinc-carbon dry cell?

Alkaline cells contain potassium hydroxide instead of ammonium chloride. Signup and view all the answers

Why are alkaline cells preferred?

Alkaline cells provide consistent power over a longer period of time. Signup and view all the answers

Indicate whether the reactant in each of the following partial equations is being oxidized or reduced:

Fe→Fe3+ = Oxidized H2O→O2 = Oxidized Sr→Sr2+ = Oxidized CH4O→CH2O = Oxidized P4→4P3− = Reduced Signup and view all the answers

Explain for Fe→Fe3+.

Loss of electrons Signup and view all the answers

Explain for H2O→O2.

Loss of hydrogen atoms Signup and view all the answers

Explain for Sr→Sr2+.

Loss of electrons Signup and view all the answers

Explain for P4→4P3−.

Gain of electrons Signup and view all the answers

Explain for CH4O→CH2O.

Loss of hydrogen atoms Signup and view all the answers

If you breathe 15 times a minute, taking in and exhaling 0.50 L of air with each breath, what volume of air do you breathe each day?

1.1×10^4 L Signup and view all the answers

Air is 21% oxygen by volume. What volume of oxygen do you breathe each day?

2300 L Signup and view all the answers

Identify the oxidizing agent.

MnO2 Signup and view all the answers

Identify the reducing agent.

Zn Signup and view all the answers

For the reaction N2+6Li→2Li3N, identify the oxidizing and reducing agents.

N2 = Oxidizing agent Li = Reducing agent Signup and view all the answers

For the reaction 2H2S+SO2→3S+2H2O, identify the oxidizing and reducing agents.

SO2 = Oxidizing agent H2S = Reducing agent Signup and view all the answers

For the reaction O3+ClO2→O2+ClO3, identify the oxidizing and reducing agents.

O3 = Oxidizing agent ClO2 = Reducing agent Signup and view all the answers

For the reaction Ag++Ti3+→Ag+Ti4+, identify the oxidizing and reducing agents.

Ag+ = Oxidizing agent Ti3+ = Reducing agent Signup and view all the answers

Label each of the following half-reactions as oxidation or reduction:

2I−→I2+2e− = Oxidation SO2+2H2O→H2SO4+2H++2e− = Oxidation Cl2+2e−→2Cl− = Reduction HNO3+H++e−→NO2+H2O = Reduction Signup and view all the answers

Classify each metal treatment by its impact on the rate of corrosion:

Placing the metal object in a moist room = Increases corrosion rate Putting strain on the metal = Increases corrosion rate Exposing the metal to an electrolyte = Increases corrosion rate Coating the metals with varnish or grease = Decreases corrosion rate Painting the metal surface = Decreases corrosion rate Electroplating the metal surface = Decreases corrosion rate Signup and view all the answers

Identify the processes occurring at the anode and cathode during the rusting of iron.

Iron (Fe) loses electrons. Fe2+ is formed. = At anode Oxygen (O) gains electrons. OH− is formed. = At cathode Signup and view all the answers

What is the balanced chemical equation for the reaction that reverses silver sulfide back into silver?

6 Ag + Al2S3 Signup and view all the answers

Classify the reactants in these chemical equations based on whether they are oxidized or reduced:

Carbon in 2C2H6+7O2→4CO2+6H2O = Oxidized Tin in Hg22++Sn2+→2Hg+Sn4+ = Oxidized Aluminum in Fe2O3+2Al→2Fe+Al2O3 = Oxidized Mercury in Hg22++Sn2+→2Hg+Sn4+ = Reduced Oxygen in 2C2H6+7O2→4CO2+6H2O = Reduced Iron in Fe2O3+2Al→2Fe+Al2O3 = Reduced Signup and view all the answers

Write a balanced reduction half-reaction for F2.

F2+2e−→2F− Signup and view all the answers

Write a balanced reduction half-reaction for N2.

N2+6e−→2N^3− Signup and view all the answers

Write a balanced reduction half-reaction for S8.

S8+16e−→8S^2− Signup and view all the answers

Combine the half-reactions to obtain a balanced overall redox reaction: 2I−→I2+2e− and Cl2+2e−→2Cl−

2I−+Cl2→I2+2Cl− Signup and view all the answers

Combine the half-reactions to obtain a balanced overall redox reaction: HNO3+H++e−→NO2+H2O and SO2+2H2O→H2SO4+2H++2e−

2HNO3+SO2→2NO2+H2SO4 Signup and view all the answers

Study Notes

Oxidation and Reduction Classification

Oxidation involves the loss of electrons or hydrogen, and gain of oxygen.
Reduction involves the gain of electrons or hydrogen, and loss of oxygen.
Examples: Ti → TiO2 is oxidation; SiO2 → Si is reduction.

Oxidation Catalyst Challenges

Organic components of catalysts are vulnerable to oxidation, complicating the design of long-lived catalysts.

Redox Agents

SO2−4 is classified as neither an oxidizing nor reducing agent.
During charging in a battery, Pb2+ can be oxidized and reduced.

Oxidized and Reducing Substances

C8H7ON is identified as the oxidized substance.
O2 is the main oxidizing agent in biological energy processes.

TNT Explosions

TNT explosions are powerful due to rapid decomposition into gaseous products.

Alkaline Cell Features

Alkaline cells use potassium hydroxide, offering improved performance over zinc-carbon cells with better power consistency.

Corrosion Influence

Corrosion is accelerated by moisture, strain on metals, and exposure to electrolytes.
Applying protective coatings (varnish, paint, electroplating) effectively reduces corrosion rates.

Rusting Process

Iron rusts in moist air, producing Fe2+ at the anode through electron loss and forming OH− at the cathode via oxygen gain.

Silver Tarnish Reversal

Silver sulfide forms from silver oxidation and can revert back to silver using aluminum in sodium bicarbonate solution, demonstrating a redox reaction where silver sulfide is reduced.

Redox Reactions

Identifying elements oxidized or reduced in reactions: Carbon and Tin are oxidized in their respective reactions, while Mercury and Oxygen are reduced.

Balanced Half-Reactions

Various half-reactions yield different products, e.g., F2 gains electrons to form F−, and N2 gains electrons to produce N^3−.

Combining Half-Reactions

Combining half-reactions facilitates the creation of balanced overall redox reactions, crucial for stoichiometric calculations in chemical equations:
- 2I− + Cl2 → I2 + 2Cl−
- 2HNO3 + SO2 → 2NO2 + H2SO4

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Description

Test your understanding of oxidation and reduction concepts in chemical reactions from Chapter 08. This quiz includes classification tasks and reasoning for the challenges in catalyst design. Perfect for reinforcing your knowledge on these essential topics in chemistry.