A solid block of a substance is heated. Thermal energy is supplied to the solid by a heater. The temperature of the solid increases until it reaches its melting point. The solid then starts to melt and change into a liquid.
Describe, in terms of molecules and their arrangement or motion, how a solid differs from a liquid.
Describe what happens to the molecules of the solid as its temperature begins to increase.
Explain, in terms of molecules, why a supply of thermal energy is needed to change the solid into a liquid at its melting point.
The density of the solid is 1.25 g/cm31.25\text{ g/cm}^31.25 g/cm3. The volume of the solid block is 80 cm380\text{ cm}^380 cm3.
The solid reaches its melting point. It now absorbs 34000 J34000\text{ J}34000 J of thermal energy and all of the solid changes into a liquid.
Calculate the specific latent heat of fusion of this substance.
specific latent heat of fusion=……………………………… \text{specific latent heat of fusion} = \dots\dots\dots\dots\dots\dots\dots\dots\dots\dots\dots\dots specific latent heat of fusion=………………………………528 exam-style questions on CIE IGCSE Physics 2.2 Thermal properties and temperature, covering 2.2.1 Thermal expansion of solids, liquids and gases, 2.2.2a Internal energy and temperature, 2.2.2b Specific heat capacity, 2.2.3a Melting, boiling, condensation and solidification, 2.2.3b Evaporation, and 2.2.3c Cooling by evaporation. Each one has a worked solution and a mark scheme showing where the marks go.