A student wanted to investigate how the pH of a solution changes as magnesium oxide is added to dilute hydrochloric acid.
They followed this method:
Step 1 Measure out 50.0 cm3 of dilute hydrochloric acid into a beaker using a measuring cylinder.
Step 2 Record the initial pH of the acid using a pH probe connected to a computer.
Step 3 Add a 0.20 g portion of magnesium oxide powder to the acid in the beaker and stir.
Step 4 Record the pH of the mixture.
Step 5 Repeat steps 3 and 4 until the pH of the mixture is constant.
Name a piece of apparatus which could be used to measure out 50.0 cm3 of dilute hydrochloric acid more accurately than the measuring cylinder.
276 exam-style questions on Edexcel GCSE Chemistry 4.1 Acids, covering 4.1.1 Acids, alkalis and the pH scale, 4.1.2 Hydrogen ion concentration and pH, 4.1.3 Dilute and concentrated, weak and strong acids, 4.1.4 Bases, alkalis and the reactions of acids, 4.1.5 Chemical tests for hydrogen and carbon dioxide, 4.1.6 Neutralisation as a reaction of acids with bases, 4.1.7 Preparing soluble salts, and 4.1.8 Solubility rules and preparing insoluble salts. Each one has a worked solution and a mark scheme showing where the marks go.