Question

The diagram below shows a cooling curve for a substance:

1. State the temperatures at which the substance condenses.
2. The temperature range in which the substance is in liquid state.
3. Why do we prefer ice to ice-cold water for cooling a drink?

Answer 1

1. The substance condenses at 150°C.
2. 150°C to 60°C.
3. At 0°C, melting 1 g of ice into water requires 336 J of heat energy from the drink. As a result, the drink releases 336 J more heat energy than 1 g ice at 0°C. As a result, 1 g of ice at 0°C produces significantly more cooling than 1 g of water at 0°C.