Steam at 100 ∘C100\ ^{\circ}\text{C}100 ∘C causes a more serious burn than the same mass of water at 100 ∘C100\ ^{\circ}\text{C}100 ∘C.
The specific latent heat of vaporisation of water is 2 260 000 J/kg2\,260\,000\ \text{J/kg}2260000 J/kg.
The specific heat capacity of water is 4200 J/kg ∘C4200\ \text{J/kg}\ ^{\circ}\text{C}4200 J/kg ∘C.
Name the change of state when steam turns into water.
Calculate the energy released when 0.0020 kg of steam at 100 ∘C100\ ^{\circ}\text{C}100 ∘C turns into water at 100 ∘C100\ ^{\circ}\text{C}100 ∘C.
Use the equation
Q=m×LQ = m \times LQ=m×L
Calculate the energy released when 0.0020 kg of water cools from 100 ∘C100\ ^{\circ}\text{C}100 ∘C to 40 ∘C40\ ^{\circ}\text{C}40 ∘C.
Use the equation
ΔQ=m×c×Δθ\Delta Q = m \times c \times \Delta \thetaΔQ=m×c×Δθ
Use your answers to (b) and (c) to explain why steam at 100 ∘C100\ ^{\circ}\text{C}100 ∘C causes a more serious burn than water at 100 ∘C100\ ^{\circ}\text{C}100 ∘C.
110 exam-style questions on Edexcel GCSE Physics 14.2 Specific heat capacity and latent heat, covering 14.2.1 Heating, temperature and changes of state, 14.2.2 Specific heat capacity and specific latent heat, 14.2.3 Specific heat capacity calculation, 14.2.4 Specific latent heat calculation, and 14.2.5 Reducing energy transfer through thermal insulation. Each one has a worked solution and a mark scheme showing where the marks go.