3.1 – Thermal concepts

• • • Understandings:

• Molecular theory of solids, liquids and gases

• Temperature and absolute temperature

• Internal energy

• Specific heat capacity

• Phase change

• Specific latent heat

Applications and skills:

• Describing temperature change in terms of internal energy

• Using Kelvin and Celsius temperature scales and converting between them

• Applying the calorimetric techniques of specific heat capacity or specific latent heat experimentally

• Describing phase change in terms of molecular behaviour

• Sketching and interpreting phase change graphs

• Calculating energy changes involving specific heat capacity and specific latent heat of fusion and vaporization

Guidance:

• Internal energy is taken to be the total intermolecular potential energy + the total random kinetic energy of the molecules

• Phase change graphs may have axes of temperature versus time or temperature versus energy

• The effects of cooling should be understood qualitatively but cooling correction calculations are not required

Data booklet reference:

• Q=mCΔT

• Q=mL