Below you can read exactly what AQA want you to know for this module. You can also find the relevant section from the specification on each page of this site. You should be aware of both what you need to know, and (just as importantly) what you DO NOT need to know. It is also important to remember that you need to be able to apply these statements to a wide range of different contexts, so you must practise this by attempting lots of different questions and reading around the subject.

3.6.2.1 Thermal energy transfer

Internal energy is the sum of the randomly distributed kinetic energies and potential energies of the particles in a body.

The internal energy of a system is increased when energy is transferred to it by heating or when work is done on it (and vice versa), eg a qualitative treatment of the first law of thermodynamics.

For a change of temperature:

$Q=mcΔθ$ where *c* is specific heat capacity.

Calculations including continuous flow.

Appreciation that during a change of state the potential energies of the particle ensemble are changing but not the kinetic energies. Calculations involving transfer of energy.

For a change of state $Q = ml$ where *l* is the specific latent heat.

3.6.2.2 Ideal gases

Gas laws as experimental relationships between *p, V, T* and the mass of the gas.

Concept of absolute zero of temperature.

Ideal gas equation: $pV = nRT$ for *n* moles and $pV = NkT$ for *N* molecules.

$$Work\; done = pΔV$$

Avogadro constant *N _{A}*, molar gas constant

Molar mass and molecular mass.

3.6.2.3 Molecular kinetic theory model

Brownian motion as evidence for existence of atoms.

Explanation of relationships between *p, V* and *T* in terms of a simple molecular model.

Students should understand that the gas laws are empirical in nature whereas the kinetic theory model arises from theory.

Assumptions leading to $$pV=\frac{1}{3}Nm\left ( c_{\mathrm{rms}} \right )^{2}$$ including derivation of the equation and calculations.

A simple algebraic approach involving conservation of momentum is required.

Appreciation that for an ideal gas internal energy is kinetic energy of the atoms.

Use of *average molecular kinetic energy =*

$$\frac{1}{2}m\left ( c_{\mathrm{rms}} \right )^{2}=\frac{3}{2}kT=\frac{3RT}{2N_{\mathrm{A}}}$$

Appreciation of how knowledge and understanding of the behaviour of a gas has changed over time.