Zinc sulphate contains $22.65\%$ of zinc and $43.9\%$ of water of crystallization. If the law of constant proportions is true,then the weight of zinc required to produce $20\, g$ of the crystals will be ............. $g$.

$5.06 \ g$ of pure cupric oxide $(CuO)$ on complete reduction gives $4.04 \ g$ of metallic copper. In another experiment,$1.3 \ g$ of metallic copper is dissolved in nitric acid and the resulting solution is carefully dried to yield $1.63 \ g$ of $CuO$. Which law of chemical combination is illustrated by these results?

Identify the symbol used for water according to $\text{Dalton's}$ atomic theory?

$45.4 \ L$ of dinitrogen reacts with $22.7 \ L$ of dioxygen to form $45.4 \ L$ of nitrous oxide. For the reaction $2N_{2(g)} + O_{2(g)} \to 2N_2O_{(g)}$,identify the law followed and state the law.

Identify the law for which the following statement is true.
"Equal volume of all gases at same temperature and pressure should contain equal number of molecules".

$n_1 \ g$ of substance $X$ reacts with $n_2 \ g$ of substance $Y$ to form $m_1 \ g$ of substance $R$ and $m_2 \ g$ of substance $S$. The reaction is represented as $X + Y \rightarrow R + S$. What is the relationship between the mass of the reactants and the mass of the products?