Define spontaneous change

Spontaneous change is change that requires no work to bring about. The mixing of gases in an isolated system

Define entropy, S

Entropy, S, is a measure of molecular disorder

Give the second law of thermodynamics

The total entropy (ie the entropy of the system, ΔS, + the entropy of the surroundings, ΔS_{Sur}) increases in the course of a spontaneous change.

Note: ΔS can be negative as long as ΔS_{Sur} is positive enough so that overall S_{total} > 0

Give the equation for dS_{total}, taking temperatures of the system and the surroundings into account

Define T_{h}, the higher temperature, as the temperature of the system and T_{c}, the lower temperature, as the temperature of the surroundings. dq is the heat transfer.

Give the equation linking dS and dq^{reversible}

Give the equation of ΔS as a state function

Derive the equation of ΔS for the isothermal expansion of an ideal gas

Derive the equation for Δ_{Trs}S at constant temperature and pressure

(Trs = phase transition)

Remember that reversible phase transitions of pure substances take place at constant temperatures, and dq = dH at constant pressure

Describe Trouton's rule

Trouton observed that the standard molar entropy of vaporisation. Δ_{vap}S^{0}m _{~ }85JK^{-1}mol^{-1} for a wide range of liquids.

This is due to similar changes in disorder when going from a liquid to a gas. Water is an exception due to the structural order (ie lower entropy) of hydrogen bonds.

Derive the equation of ΔS when a material is heated at constant pressure

Note that C_{p} is assumed to be independent of temperature

State the third law of thermodynamics

The entropy of all perfect crystalline substances is zero at T = 0

Derive an equation to work out the entropy for any given temperature

Combining entropy changed upon heating and during phase transitions, we can calculate the entropy for any given temperature

Give the equation for standard reaction entropy

Give the equation for the standard reaction enthalpy at T_{2} if we know the quantity at T_{1}

Describe the total entropy change for any irreversible reaction

Describe the total entropy change for any reversible reaction

Give and describe the Clausius inequality

This is a criterion for irreversible/ spontaneous change. It is very useful in judging the spontaneity of chemical reactions

Define G, the Gibbs free energy

G = H - TS

dG = dH - TdS

Temperature and pressure are constant

Give dG for spontaneous processes

dG < 0

Derive dG = Vdp - SdT by combining the first and second laws of thermodynamics

Note: use the product rule

Derive the equation of the Gibb's free energy at pressure p, where T is held constant.

Denote G^{0} as the standard Gibbs free energy

Modify the equation for G(p) for a mixture of gasses, denoting p_{A} and p_{B} as the partial pressures of reactants