the factors determining the relative solubility of a solute in aqueous and non-aqueous solvents

Intermolecular bonds, ion-dipole bonds and ionic bonds should be considered.

the terms hydrated ions, enthalpy change of solution (∆_solH), lattice enthalpy (∆_LEH) and enthalpy change of hydration of ions (∆_hydH), and:

(i) the solution of an ionic solid in terms of enthalpy cycles and enthalpy level diagrams involving these terms
(ii) use of these enthalpy cycles to perform calculations
(iii) techniques and procedures for measuring the energy transferred in experiments involving enthalpy changes in solution

Lattice enthalpy defined as an exothermic quantity.

the dependence of the lattice enthalpy of an ionic compound and the enthalpy change of hydration of ions on the charge density of the ions

The greater the charge density of the ions:
- the greater the electrostatic attraction and the more exothermic the lattice enthalpy
- the greater the attraction of water molecules and the more exothermic the hydration enthalpy.

qualitative entropy changes (of the system);
entropy as a measure of the number of ways that molecules and their associated energy quanta can be arranged

qualitative predictions of the ∆_sysS for a reaction in terms of:

(i) the differences in magnitude of the entropy of a solid, a liquid and a gas
(ii) the difference in number of particles of gaseous reactants and products

the expressions: \(∆_{tot}S = ∆_{sys}S + ∆_{surr}S\) and \(∆_{surr}S = -\dfrac{∆H}{T}\);
calculations using these expressions;
the relation of the feasibility of a reaction to the sign of ∆_totS

calculation of ∆_sysS for a reaction given the entropies of reactants and products

the term solubility product for ionic compounds;
solubility product calculations;
techniques and procedures for determining solubility products

the Brønsted–Lowry theory of acids and bases:

(i) acids as proton donors and bases as proton acceptors
(ii) the identification of the proton donor and proton acceptor in an acid-base reaction
(iii) the terms conjugate acid and conjugate base

Theory of acids and bases

the terms strong acid, strong base;
equations for their ionisation in water

Strong and weak acids

the term weak acid and equations for its ionisation in water;
acidity constant (‘dissociation constant’) K_a, pK_a;
techniques and procedures to measure the pH of a solution

Strong and weak acids

the term pH, and pH calculations involving:

(i) strong acids
(ii) strong bases, using K_w
(iii) weak acids (including calculating any of the terms pH, K_a and concentration from any two others, being aware of the approximations made)

The value of K_w is given on the Data Sheet.
Quadratic equations are not required.

pH Strong and weak acids Strong and weak bases

buffer solutions based on solutions of weak acids and their salts:

(i) the meaning of the term buffer
(ii) how buffers work (including in everyday applications)
(iii) buffer solution calculations

Buffer solutions

the ‘greenhouse effect’, in terms of:

(i) solar energy reaching Earth mainly as visible and UV
(ii) Earth absorbing some of this energy, heating up and radiating IR
(iii) greenhouse gases (e.g. carbon dioxide and methane) in the troposphere absorbing some of this IR, in the ‘IR window’
(iv) absorption of IR by greenhouse gas molecules increases the vibrational energy of their bonds, the energy is transferred to other molecules by collisions, thus increasing their kinetic energy and raising the temperature
(v) greenhouse gas molecules also re-emitting some of the absorbed IR in all directions, some of which heats up the Earth
(vi) increased concentrations of greenhouse gases leading to an enhanced greenhouse effect.