Oxidation-Reduction Equations

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This is a 7 point assignment.

OBJECTIVES: After having completed this unit, students should be able to:

1. Identify oxidation-reduction (redox) reactions
2. Define the terms oxidation and reduction in terms of loss or gain of electrons and impact on oxidation state
3. Identify which element is oxidized and which element is reduced in a redox reaction
4. Assign oxidation states to the elements in a compound or ion.
5. Predict the products for the single replacement reaction of a metal with an acid, water, or salt and use the activity series to predict whether a reaction will occur
6. Identify oxidizing and reducing agents in redox reactions.
7. Balance oxidation-reduction reactions using the half-reaction method in both acidic and basic solutions.

Reading and Homework Exercises

Table of Contents from: OpenStax Chemistry 2e: Chapter 4, section 4.2  (Oxidation-Reduction Reactions only)

4.2 Classifying Chemical Reactions (Oxidation-Reduction Reactions Only)

Assigning Oxidation Numbers: You should be able to assign an oxidation number to each element in any of the following in a formula:

• elements
• monatomic ions
• polyatomic ions
• molecular compounds
• ionic compounds

In Questions 1-12, you will be asked to assign oxidation states of each element in the chemical formulas.

Question 1: Fe

Question 2: Cl₂

Question 3: Fe²⁺

Question 4: Cl^1-

Question 5: CaBr₂

Question 6: Mg₃P₂

Question 7: NO₂

Question 8: N₂O₅

Question 9: NO₃^1-

Question 10: Na₂S₂O₃

Question 11: IO₄^1-

Question 12: Ba(IO₃)₂

In Questions 13-15, you can check your ability to identify whether a reaction is an oxidation/reduction (redox) reactions and identify  whether reactants are oxidized or reduced.  You are also asked to identify oxidizing and reducing agents.

Question 13:

Considering the following redox reaction answer the question below:

Li₂SO₄ + Zn → 2 Li + ZnSO₄

Question 14:

Considering following the redox reaction answer the question below:

3 Fe²⁺ + NO₃^–  + 4 H⁺→ 3 Fe³⁺ + NO  + 2 H2O 

Question 15:

Questions 16-18 cover a specific type of redox reactions known as Single Replacement Reactions.  See pages 17-23 in the Chemical Reactions Handout (located in the Unit 3 Folder in the course D2L site) for additional info on single replacement reactions (including the activity series of metals) and help with the following questions.

Question 16:

Mg + AgI→

Question 17:

Ni + H₃PO₄→

Question 18:

Cu + Al₂O₃→

Questions 19 and 20 give you practice on balancing redox reactions.  On a test or exam, you will be expected to balance the reaction without being coefficients to drag and drop.  Therefore, to get the maximum benefit from this homework practice it is recommended that you balance the equation on paper (as you would be required to do on the exam) then drag and drop to check your resulting balanced equation.

Question 19: A redox reaction between dichromate ion and hydrogen sulfide is carried out in acidic solution.

Cr₂O₇^2- + H₂S → Cr³⁺ + S

Answer the following question:

Question 20: A redox reaction between aluminum ion and nitrogen monoxide is carried out in basic solution.

Al³⁺ + NO → HNO₂ + Al

Answer the following question: