AP Chemistry Unit 4.9: Redox Equations

Practice AP Chemistry Unit 4.9 questions on constructing oxidation half-reactions and combining them into balanced net ionic redox equations with conserved atoms and charge.

Exam points

Use molecular and particle models to explain solubility, intermolecular forces, and solution behavior in water.
Interpret concentration, polarity, and equilibrium data to predict dissolution, precipitation, and species changes.

Covered syllabus points

4.9.A—Represent a balanced redox reaction equation using half-reactions

[Maximum number: 2]

A scientist constructs a galvanic cell as shown in the diagram. As the cell operates, the $\mathrm{Zn}(s)$

electrode increases in mass and the $\mathrm{Al}(s)$ electrode decreases in mass. A data table with the

standard reduction potentials for the substances follows the diagram.

Figure for Question 4.9 Oxidation-Reduction (Redox) Reactions question 1 — AP Chemistry

Table for Question 4.9 Oxidation-Reduction (Redox) Reactions question 1 — AP Chemistry

(a)

Write the half-reaction for the oxidation that occurs at the anode.

[ 1 ]

A For the correct equation (state symbols not required):

Point 01

$\mathrm{Al}(s) \rightarrow \mathrm{Al}^{3+}(a q)+3 e^{-}$

(b)

Write the balanced net ionic equation for the overall reaction that occurs in the galvanic cell.

[ 1 ]

B For the correct balanced net ionic equation (state symbols not required):

Point 02

$2 \mathrm{Al}(s)+3 \mathrm{Zn}^{2+}(a q) \rightarrow 2 \mathrm{Al}^{3+}(a q)+3 \mathrm{Zn}(s)$

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Covered syllabus points

4.9 Oxidation-Reduction (Redox) Reactions question 1

Question (a)

Question (b)