Limescale forms inside kettles in some areas. Limescale is mainly calcium carbonate.
A kettle descaler contains an acid. When the descaler is added to the kettle, the limescale fizzes and starts to disappear.
Name the gas that causes the fizzing.
The descaler has a pH of 2.
The descaler is left in the kettle until the fizzing stops. Some limescale is still left in the kettle.
Describe and explain how the pH of the solution in the kettle changes.
A student models this reaction using calcium carbonate and dilute hydrochloric acid.
Complete the balanced symbol equation for the reaction.
CaCO₃ + ...... HCl → CaCl₂ + H₂O + ......
The student then adds a piece of magnesium ribbon to dilute sulfuric acid.
Name the two products of this reaction.
The student adds black copper oxide powder to warm dilute sulfuric acid. The copper oxide reacts and a blue solution forms. No gas is given off.
Copper oxide is a base. Name the type of reaction between an acid and a base.
Complete the word equation for this reaction.
copper oxide + sulfuric acid → ...... + ......
112 exam-style questions on OCR GCSE Chemistry 3.3 Types of chemical reactions, covering 3.3.1 Oxidation and reduction in terms of oxygen, 3.3.2 Acids, alkalis and neutralisation, 3.3.3 The pH scale and measuring pH, 3.3.4 Oxidation and reduction in terms of electrons, 3.3.5 Dilute and concentrated, weak and strong acids, and 3.3.6 Hydrogen ion concentration and pH. Each one has a worked solution and a mark scheme showing where the marks go.