Thermal decomposition

The list gives four experiments carried out with calcium carbonate.

1 acid added

2 alkali added

3 heated strongly

4 water added

Which experiments produce carbon dioxide?

• 1 and 2

• 1 and 3

• 2 and 3

• 2 and 4

Which metal carbonate does not produce carbon dioxide when it is heated with a Bunsen burner?

• copper(II) carbonate

• magnesium carbonate

• sodium carbonate

• zinc carbonate

Which process does not produce carbon dioxide?

• combustion of hydrocarbons

• photosynthesis

• respiration

• thermal decomposition of limestone

Information about the nitrates and carbonates of two metals, Q and R, is shown.

Which statement is correct?

• Q is calcium and R is magnesium.

• Q is magnesium and R is sodium.

• Q is potassium and R is copper.

• Q is sodium and R is calcium.

Calcium nitrate decomposes when it is heated.

What is the equation for the thermal decomposition of calcium nitrate?

• 2Ca(NO₃)₂ → 2CaO + O₂ + 4NO₂

• Ca(NO₃)₂ → Ca(NO₂)₂ + O₂

• Ca(NO₃)₂ → Ca + O₂ + 2NO₂

• Ca(NO₃)₂ → Ca + 3O₂ + N₂

Some metal nitrates and carbonates decompose when heated strongly.

Metal Q has a nitrate that decomposes to give a salt and a colourless gas only.

The carbonate of metal Q does not decompose when heated with a Bunsen burner.

What is metal Q?

• calcium

• copper

• sodium

• zinc