Exam Focus

🎯 Exam Focus

Frequently Examined

Specific latent heat is a popular calculation topic. Examined in Edexcel 1PH0/2 (Paper 2). Edexcel uses context-based questions around material properties and industrial processes — refrigeration cycles, cooking, industrial drying — so be ready to apply E = mL to unfamiliar contexts. Edexcel 1PH0/2 may provide the latent heat value in the question or require you to select between Lf and Lv for a given scenario.

• Calculation: E = mL (2-3 marks): Given mass and L, find energy. Or rearrange to find mass. Always show working and include units (J).
• Explain why L_v > L_f (3 marks): Link to bond-breaking — melting loosens bonds (particles stay close), boiling completely breaks all bonds (particles separate fully).
• Explain why temperature stays constant (3 marks): Energy → breaking bonds → potential energy increases, kinetic energy unchanged → temperature unchanged.
• Steam vs boiling water context question (2 marks): Steam releases latent heat of vaporisation when it condenses, giving more total energy transfer to skin.
• "Suggest" questions (Edexcel): Given an unusual state change scenario, suggest which latent heat value applies (fusion vs vaporisation) and calculate the energy involved.