Understand C 4.2.3 and C 4.2.6 - Soluble Salts and Strong and Weak Acids
Channel: Hands on Chemistry
Date: 2020-07-10

AQA Specification Notes:
Soluble salts can be made from acids by reacting them with solid insoluble substances, such as metals, metal oxides, hydroxides or carbonates. The solid is added to the acid until no more reacts and the excess solid is filtered off to produce a solution of the salt.
Salt solutions can be crystallised to produce solid salts.

Students should be able to describe how to make pure, dry samples
of named soluble salts from information provided.

C 2.3.6 Strong and Weak Acids

A strong acid is completely ionised in aqueous solution. Examples of strong acids are hydrochloric, nitric and sulfuric acids.
A weak acid is only partially ionised in aqueous solution. Examples of weak acids are ethanoic, citric and carbonic acids.
For a given concentration of aqueous solutions, the stronger an acid, the lower the pH.
As the pH decreases by one unit, the hydrogen ion concentration of the solution increases by a factor of 10.

Students should be able to:
• use and explain the terms dilute and concentrated (in terms of amount of substance), and weak and strong (in terms of the degree of ionisation) in relation to acids