STUDENT SPACE · TOPIC 4

Carbon compounds and carbonates

Apply combustion, gas tests and carbonate equations to linked problems.

The essentials

Complete combustion: CH₄ + 2O₂ → CO₂ + 2H₂O. Limited oxygen may produce CO or carbon particulates.
Carbonate + acid produces salt, water and carbon dioxide. Confirm the gas using limewater.
Heating limestone decomposes calcium carbonate: CaCO₃ → CaO + CO₂. This also occurs in the blast furnace.
CO₂ + Ca(OH)₂ → CaCO₃ + H₂O. Insoluble calcium carbonate causes the milky appearance.

Try each question before opening its hint or answer. Use paper for calculations and diagrams.

Why does incomplete combustion require particular concern in an enclosed space?

Need a hint for Question 1?

Decide whether the carbonate is heated or reacts with acid. Write correct product formulae before balancing.

Check Question 1

Toxic carbon monoxide can form and accumulate. It prevents effective oxygen transport in the blood.

Write a balanced equation for calcium carbonate reacting with hydrochloric acid.

Need a hint for Question 2?

Acid plus carbonate makes a salt, water and a gas.

Check Question 2

CaCO₃ + 2HCl → CaCl₂ + H₂O + CO₂.

Write the thermal decomposition equation for calcium carbonate and name the solid product.

Need a hint for Question 3?

Heating a metal carbonate can form its oxide and carbon dioxide.

Check Question 3

CaCO₃ → CaO + CO₂. Calcium oxide.

Use Lesson 4 in your worksheet for written practice. Your teacher will discuss those answers in class.