A teacher investigates the reactions of copper carbonate, CuCO3\text{CuCO}_3CuCO3.
The diagram shows the reactions the teacher does.

State the name of the soluble salt, X.
State the name of gas Y.
Gas Z bleaches damp litmus paper. State the name of gas Z.
The teacher performs a flame test of the copper made by the electrolysis of X. What colour flame does the teacher observe?
Lead metal is extracted from lead oxide by heating with carbon as shown in the equation:
lead oxide+carbon→lead+carbon dioxide\text{lead oxide} + \text{carbon} \rightarrow \text{lead} + \text{carbon dioxide}lead oxide+carbon→lead+carbon dioxide
Explain why lead can be extracted this way. Use ideas about the reactivity series.
Complete the table below by identifying the missing metals or uses.
| Alloy | Main metals | Uses |
|---|---|---|
| high carbon steel | iron and ......................... | cutting tools |
| stainless steel | iron, chromium, and ......................... | cutlery |
| brass | copper and zinc | ......................... |