Limescale builds up inside kettles in hard-water areas. Limescale is mainly calcium carbonate, CaCO3\mathrm{CaCO_{3}}CaCO3. It can be removed with dilute hydrochloric acid. The reaction forms calcium chloride, water and carbon dioxide.
Write the word equation for the reaction.
Calcium chloride contains Ca2+\mathrm{Ca^{2+}}Ca2+ ions and Cl−\mathrm{Cl^{-}}Cl− ions. Give the formula of calcium chloride.
Balance the equation for the reaction: CaCO3+HCl→CaCl2+H2O+CO2\mathrm{CaCO_{3}} + \mathrm{HCl} \rightarrow \mathrm{CaCl_{2}} + \mathrm{H_{2}O} + \mathrm{CO_{2}}CaCO3+HCl→CaCl2+H2O+CO2
Calcium chloride dissolves in water. Rewrite the balanced equation with state symbols for every substance.
Describe the test for carbon dioxide and give the result.
A student carries out the reaction in an open beaker on a balance. The reading on the balance decreases during the reaction. Explain why.
47 exam-style questions on Edexcel GCSE Chemistry 1.1 Formulae, equations and hazards, covering 1.1.1 Formulae, word and balanced equations, 1.1.2 Balanced ionic equations, and 1.1.3 Hazard symbols and risk in practical work. Each one has a worked solution and a mark scheme showing where the marks go.