If copper metal is heated over a flame, it develops a coating. What is the colour and composition of this coating?

Balance the following chemical equation:
$Fe(s) + H_2O(g) \rightarrow Fe_3O_4(s) + H_2(g)$

Which among the following statement$(s)$ is(are) true? Exposure of silver chloride to sunlight for a long duration turns grey due to:
$(i)$ The formation of silver by decomposition of silver chloride
$(ii)$ Sublimation of silver chloride
$(iii)$ Decomposition of chlorine gas from silver chloride
$(iv)$ Oxidation of silver chloride

What happens when a piece of aluminium metal is added to dilute hydrochloric acid?

$2 \, g$ of ferrous sulphate crystals are heated in a boiling tube.
$(i)$ State the colour of ferrous sulphate crystals both before heating and after heating.
$(ii)$ Name the gases produced during heating.
$(iii)$ Write the chemical equation for the reaction.

State what happens when:
$(a)$ Hydrated copper sulphate is heated.
Also,write the chemical equation for the reaction.