Question

The diagram in Figure below shows the change of phase of a substance on a temperature time graph on heating the substances at a constant rate.

1. What do the parts AB, BC, CD and DE represent?
2. What is the melting points of the substance?
3. What is the boiling points of the substance?

Answer 1

1. AB part shows rise in temperature of solid from 0°C to t₁°C, BC part shows melting at temperature t₁°C, CD part shows rise in temperature of liquid from t₁°C to t₃°C, DE part shows boiling at temperature t₃°C.
2. t₁°C is the melting point of a substance.
3. t₃°C is the boiling point of a substance.