Physics 9702 · AS & A Level · Specific heat capacity and specific latent heat

Specific heat capacity and specific latent heat — practice question

(a)[2]

With a simple kinetic model of matter, describe the arrangement of particles in a solid.

(b)[1]

The specific latent heat of vaporisation is much greater than the specific latent heat of fusion for the same substance. Explain this in terms of the spacing of molecules.

(c)

A heater provides energy at a constant rate to $0.045\,\text{kg}$ of a substance. The change in the substance's temperature with time is shown in Fig. 3.1. The substance is perfectly insulated from its surroundings.

(c(i))[1]

Determine the temperature at which the substance melts.

(c(ii))[3]

The heater has a power of $150\,\text{W}$. Use data from Fig. 3.1 to calculate, in $\text{kJ kg}^{-1}$, the specific latent heat of vaporisation $L$ of the substance.

(c(iii))[1]

Suggest what conclusion can be drawn from the fact that section $Q$ on the graph is less steep than section $P$.

Worked solution & mark scheme

This 8-mark question has a full step-by-step worked solution and mark scheme. One marking point: Particles are extremely close together or in contact

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