These eight questions cover every lesson in SPM Chemistry manufactured materials. Write a full answer on paper before opening each block.
Questions
Question 1. State two properties of a ceramic. [2 marks]
Answer
Any two of: hard, brittle, resists heat, does not conduct electricity, chemically unreactive. For example, “hard and does not conduct electricity”.
Question 2. Name the main substance in all types of glass, and state one extra substance in soda-lime glass. [2 marks]
Answer
The main substance is silica (silicon dioxide). Soda-lime glass also contains sodium carbonate and calcium oxide, so either of these earns the second mark.
Question 3. Pewter is an alloy of tin with small amounts of antimony and copper. Explain why pewter is harder than pure tin. [3 marks]
Answer
Pure tin has atoms of the same size in orderly layers, and the layers slide easily. In pewter, the antimony and copper atoms have different sizes and disrupt the orderly arrangement of tin atoms. The layers are harder to slide, so pewter is harder.
Question 4. A chemistry teacher wants beakers that can be heated strongly and cooled quickly. Choose a glass and explain. [3 marks]
Answer
Borosilicate glass. It contains boron oxide, which gives it a low thermal expansion, so it does not crack when heated or cooled quickly. It also resists chemical attack, which suits repeated use with reagents.
Question 5. Explain why a plug casing is made from a thermosetting polymer and not a thermoplastic. [3 marks]
Answer
A plug warms up when current flows, so the casing must not soften. A thermosetting polymer has cross-links between its chains, so it stays hard when heated and keeps its shape. It is also an electrical insulator, which keeps the user safe.
Question 6. Why is lead crystal glass used for decorative glasses but not for windows? Give one reason for each. [2 marks]
Answer
Lead crystal glass has a high refractive index, so it sparkles, which suits decoration. It is heavy and more costly than soda-lime glass, which is why ordinary windows use soda-lime glass instead.
Question 7. A reinforced concrete beam contains steel bars. State what concrete and steel each contribute. [2 marks]
Answer
Concrete resists pressing forces (compression) and is cheap. Steel bars resist pulling forces (tension), so together the beam does not crack when it bends.
Question 8. A drone body must be light, strong, rust-free in rain and easy to mould into curves. Choose aluminium alloy, ceramic or carbon fibre composite and justify it. [4 marks]
Answer
Carbon fibre composite meets all four requirements. The fibres give strength and the polymer gives shape, so it is light and strong. It does not corrode in rain, and it can be moulded into curves.
Ceramic is brittle and heavy, so it would shatter in a crash. Aluminium alloy is light and strong but harder to shape into complex curves, so the composite fits the requirements better.
If you got these wrong
Questions 1, 2 and 6 test recall of glass and ceramics. Return to comparing glass and ceramic applications.
Question 3 needs the layer-sliding frame from explaining alloy properties using structure. Questions 5 and 7 are covered in relating polymer and composite properties to uses. Question 8 uses the method in evaluating a material choice using given requirements.
To build a timed session from your weakest questions, use the timed original practice session builder. For help with written explanations, see online one-to-one Chemistry tuition.