Study Notes
Specific heat capacity and specific latent heat are concepts related to the energy required to change the temperature or state of a substance.
- Specific Heat Capacity — the energy required to raise the temperature of 1 kg of a substance by 1 °C or 1 K. Example: Water has a high specific heat capacity, meaning it heats up and cools down slowly.
- Latent Heat — the energy required to change the state of 1 kg of a substance without changing its temperature. Example: The specific latent heat of fusion is the energy needed to change ice to water without temperature change.
- Specific Latent Heat of Fusion — energy required to convert 1 kg of solid to liquid without temperature change. Example: Melting ice into water.
- Specific Latent Heat of Vaporisation — energy needed to convert 1 kg of liquid to gas without temperature change. Example: Boiling water into steam.
Exam Tips
Key Definitions to Remember
- Specific heat capacity is the energy required to raise the temperature of 1 kg of a substance by 1 °C or 1 K.
- Latent heat is the energy required to change the state of 1 kg of a substance without altering its temperature.
Common Confusions
- Confusing specific heat capacity with latent heat.
- Forgetting that during a change of state, temperature does not change.
Typical Exam Questions
- What is specific heat capacity? The energy required to raise the temperature of 1 kg of a substance by 1 °C or 1 K.
- What is the specific latent heat of fusion? The energy required to convert 1 kg of solid to liquid without temperature change.
- Why is more energy required for vaporisation than fusion? Because vaporisation involves breaking intermolecular forces completely.
What Examiners Usually Test
- Understanding of the difference between specific heat capacity and latent heat.
- Ability to calculate energy changes using the formulas for specific heat capacity and latent heat.