Chemistry writing conventions + G10 Notes

Single arrows are required for:

• Half-reactions and redox reactions written from the standard electrode potential table, even though the SAGS elsewhere acknowledges these are technically reversible

• Ionisation equations for the strong acids — HCℓ, HNO₃, H₂SO₄

• Dissociation equations for strong bases — Group 1 metal hydroxides

• All organic reaction equations (substitution, addition, elimination, esterification, combustion)

Double/reversible arrows are required for:

• Ionisation equations for weak acids — HF, H₃PO₄, H₂SO₃, H₂CO₃, oxalic acid, ethanoic acid and other carboxylic acids.

• Ionisation of ammonia (the one weak base) in water.

• Hydrolysis equations for NH₄⁺ and the anions of weak acids.

• Any general chemical equilibrium reaction

Where does the solvent go if it is uninvolved in the reaction?

Above the arrow in a chemical calculation

Where does the catalyst / reaction condition go in a reaction?

Above the arrow as in textbooks OR in brackets on the side (SAGS). What gets marked is whether you identified the correct condition / catalyst.

What is Ionisation?

The reaction of a molecular substance with water to produce ions

What is Dissociation?

The splitting of an ionic compound into its ions

What is a Saturated Solution?

A solution which has the maximum quantity of solute per unit volume of solvent at a particular temperature

What is an Ion-Exchange Reaction

A reaction where the positive ions (the cations) exchange their respective negative ions (the anions) to form an insoluble salt. (Also known as a precipitation reaction.)