Physics 5054 · O Level · Transfer of thermal energy

Transfer of thermal energy — practice question

Fig. 3.1 shows a small block of ice at 0^{\circ}C together with a plastic cup containing 0.24 kg of water. Diagram labels: block of ice, plastic cup, water. At the start, the water in the cup is 22.0^{\circ}C. The block of ice is placed into the water.
(a)[2]

Describe, in terms of molecules, how energy is passed by conduction from the water to the ice.

(b(i))[2]

All the ice melts and, once equilibrium is reached, the water in the cup is at 6.0^{\circ}C. The specific heat capacity of water is $4200\,\text{J}/(\text{kg}\,^{\circ}\text{C})$. Calculate the energy lost by the 0.24 kg of water as it cools.

(b(ii))[2]

Describe how the molecular structure of water at 6.0^{\circ}C is different from the molecular structure of ice at 0^{\circ}C.

(b(iii))[1]

The plastic cup containing water at 6.0^{\circ}C is left in a room where the room temperature is 22.0^{\circ}C. The temperature of the water in the cup rises slowly until it reaches room temperature. When the water at 6.0^{\circ}C is left in a metal cup, the temperature of the water rises to room temperature more quickly. State why the water returns to room temperature more quickly when the cup is made from metal.

Worked solution & mark scheme

This 7-mark question has a full step-by-step worked solution and mark scheme. One marking point: Collisions occur between water molecules and molecules in the ice

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