๐ฏ Common Question Types:
- Calculate energy needed to change state using E = mL (2-3 marks)
- Explain why temperature stays constant during state change (3 marks)
- Explain why Lv is greater than Lf (3 marks)
- Interpret heating/cooling curve with latent heat sections (2-3 marks)
๐ Key Command Words:
- Calculate: Use E = mL, show each step, give correct units (J)
- Explain: Must link energy โ bonds โ kinetic/potential energy โ temperature
- Compare: State values and explain the difference in terms of bond-breaking
- Suggest: May ask why steam is more dangerous than boiling water
โ ๏ธ Common Mistakes to Avoid:
- Confusing E = mcฮT (temperature change) with E = mL (state change) โ different equations for different situations
- Saying latent heat increases temperature โ it does NOT; temperature stays constant
- Forgetting units โ L is in J/kg, E is in J, m is in kg
- Saying Lf > Lv โ vaporisation always needs more energy than fusion
Quick Check: How much energy is released when 0.5 kg of steam condenses to water at 100ยฐC? (Lv = 2,260,000 J/kg)
E = m ร L = 0.5 ร 2,260,000 = 1,130,000 J (1130 kJ). This energy is released into the surroundings when bonds form during condensation โ this is why steam releases so much more energy than hot water.
This exam tips covers Exam Tips for Specific Latent Heat within Specific Latent Heat for GCSE Physics. Revise Specific Latent Heat in Particle Model for GCSE Physics with 13 exam-style questions and 30 flashcards. This is a high-frequency topic, so it is worth revising until the explanation feels precise and repeatable. It is section 11 of 12 in this topic. Treat this as a marking guide for what examiners are looking for, not just a fact list.
Practice questions for Specific Latent Heat
What is specific latent heat?
During a state change, energy is being supplied to a substance but the temperature does not change. Explain where this energy goes.