3.5.1 (8) Thermodynamics - Entropy

Front 1

Entropy (S) is:

- Its units are?

Back 1

A measure of disorder in a system.

- J K^-1 mol^-1

Front 2

Absolute entropy is:

Back 2

The entropy measured under standard conditions.

Front 3

Entropy is affected by 4 things:

Back 3

1) The temperature.

2) The dissolution.

3) The number of particles.

4) The structure of the molecule.

Front 4

Temperatures affect on entropy:

- A phase change?

Back 4

As the temperature increases, entropy gradually increases also.

- When a phase change occurs, e.g. from a solid to a liquid, there is a sudden large entropy change.

Front 5

Physical states and entropy:

1) Solids?

2) Liquids?

3) Gasses?

Back 5

1) Solids are entropically weak because the particles are in fixed positions so disorder is low.

2) Liquids are entropically average as their particles can slide around.

3) Gasses are entropically strong because the particles are free to 'whiz around' wherever.

Front 6

Dissolutions affect on entropy:

Back 6

Dissolving a solid increases the entropy as the particles go from being fixed (low disorder) to being able to slide around (average disorder).

Front 7

The particle numbers affect on entropy:

Back 7

More particles = more entropy as their are more particle arrangements possible.

Front 8

The structures impact on entropy:

- Giant covalent Vs Simple covalent?

Back 8

Giant covalent structures are entropically weak whereas simple covalent structures are entropically strong.

Front 9

Formula for ∆S:

Back 9

∆S = ∑S(products) - ∑S(reactants)