BRAINCAKEExam-style Question 4
Question (3 marks): Copper reacts with concentrated nitric acid to give copper(II) nitrate, nitrogen dioxide and water. Use oxidation numbers to balance the equation:
Cu + HNO3 → Cu(NO3)2 + NO2 + H2O
Step 1: find the changes. Copper goes from 0 to +2, an increase of 2. In HNO3, nitrogen is +5 (1 + x + 3(−2) = 0). In NO2 it is +4 (x + 2(−2) = 0), a decrease of 1. The nitrogen in Cu(NO3)2 stays at +5.
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Key terms in this lesson
- oxidising agent
- A substance that accepts electrons from another species, causing it to be oxidised, while it is itself reduced.
- reducing agent
- A substance that donates electrons to another species, causing it to be reduced, while it is itself oxidised.
More in Oxidation and Reduction
- Example Question 1
- Example Question 2
- Ionic Equations
- Exam-style Question 1
- Exam-style Question 2
- Exam-style Question 3
- Exam-style Question 5
- Exam-style Question 6
All 14 lessons in Oxidation and Reduction · All Edexcel AS-level Chemistry topics