Question 1
Is Cu²⁺ + 2e⁻ → Cu oxidation or reduction? Explain.
Need a hint for Question 1?
Give the oxygen definition first, then ask which side of the half-equation contains electrons.
Check Question 1
Reduction: Cu²⁺ gains electrons.
STUDENT SPACE · TOPIC 1
Oxygen and electron transfer
Explain oxidation and reduction using oxygen and electrons.
The essentials
- Oxidation is gain of oxygen. Reduction is loss of oxygen.
- Oxidation is loss of electrons; reduction is gain of electrons.
- In Mg + Cl₂ → MgCl₂, magnesium loses two electrons and chlorine gains them.
Key vocabulary
| English | Chinese |
|---|---|
| oxidation | 氧化 |
| reduction | 还原 |
| electron transfer | 电子转移 |
| half-equation | 半方程式 |
Quick practice
Try each question before opening its hint or answer. Use paper for calculations and diagrams.
Question 2
For CuO + H₂ → Cu + H₂O, identify the substance oxidised and the substance reduced.
Need a hint for Question 2?
Follow the gain and loss of oxygen.
Check Question 2
H₂ is oxidised by gaining oxygen. CuO is reduced by losing oxygen.
Question 3
Complete: Zn → Zn²⁺ + __ ; Br₂ + __ → 2Br⁻.
Need a hint for Question 3?
Balance charge by adding electrons to the appropriate side.
Check Question 3
Zn → Zn²⁺ + 2e⁻; Br₂ + 2e⁻ → 2Br⁻.
Use Lesson 1 in your worksheet for written practice. Your teacher will discuss those answers in class.