A pan containing ice at –15°C is placed on a gas heater as shown in Fig. 3.1. [Figure 3.1]

1. (a)Thermal conduction occurs in the metal from which the pan is made. By referring to particles, describe the process of thermal conduction in a metal.[2]
2. (b)(i)State the melting temperature of ice in kelvin. melting temperature = ........................................................... K[1]
3. (b)(ii)Explain why the temperature of the water is constant as the ice melts.[2]
4. (b)(iii)The initial mass of ice in the pan is 1.5kg and the initial temperature is –15°C. The specific heat capacity of ice is 2100J/(kg°C). Calculate the energy required to warm the ice to its melting temperature. energy = ........................................................... J[2]
5. (b)(iv)All the energy transferred to the pan comes from the heater. Using your answer to (iii) and Fig. 3.2, determine the power of the heater used to warm the ice. power = ........................................................... W[2]
6. (b)(v)The graph in Fig. 3.2 has a smaller gradient when the water is liquid than when it is solid. Suggest one reason why.[1]

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