When the temperature of a liquid increases, the kinetic energy of its particles increases and the liquid expands.

1. (a)Explain, by referring to particles, why a liquid expands when heated.[2]
2. (b)(i)State the name of the method of thermal energy transfer that causes energy to be transferred to the water that is touching the heater.[1]
3. (b)(ii)Explain how thermal energy is transferred through all of the water in the kettle.[3]
4. (b)(iii)State the boiling temperature of water at standard atmospheric pressure. Include the unit in your answer.[1]
5. (b)(iv)The kettle contains 2.5 kg of water at standard atmospheric pressure. The specific heat capacity of water is 4200 J/(kg °C). When the water reaches its boiling temperature, the kettle switches off. Calculate the increase in the internal energy of the water. increase in internal energy = ........................................................................ J[3]