CIE iGCSE Co-Ordinated Science C2.6 Giant covalent structures Exam Style Questions Paper 1
▶️ Answer/Explanation
Each carbon atom is covalently bonded to three others within its layer, leaving weak forces between separate layers.
The diagram showing this layered hexagonal sheet structure, rather than a 3D tetrahedral lattice, represents graphite.
✅ Answer: (A)
Question
Which row describes the volatility and electrical conductivity of liquid covalent compounds?
| volatility | electrical conductivity | |
|---|---|---|
| A | high | high |
| B | high | low |
| C | low | high |
| D | low | low |
▶️Answer/Explanation
Answer: B. high, low
Explanation: Liquid covalent compounds are generally volatile (high volatility) because they have weak intermolecular forces. They also have low electrical conductivity because they do not contain free ions or electrons to carry charge.
Question
Which statements describe carbon?
1. It forms basic oxides.
2. It is used as an electrode in electrolysis.
3. It is used to extract iron from its ore.
A. 1, 2 and 3
B. 1 and 2 only
C. 1 and 3 only
D. 2 and 3 only
▶️Answer/Explanation
Answer: D
Explanation: Carbon is used as an electrode in electrolysis (statement 2) and is used in the extraction of iron from its ore (statement 3). However, carbon does not form basic oxides (statement 1 is incorrect).