Zinc sulfate crystals contain $22.65\%$ of zinc and $43.9\%$ of water. If it follows the law of definite proportions,how many grams of $Zn$ are required to obtain $20 \, g$ of crystals?

Statement $1$: Creation or destruction of atoms is not possible.
Statement $2$: Under identical conditions of temperature and pressure,the number of atoms/molecules in a given volume of gas is not the same.

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 ............. $g$.

Which of the following pairs of compounds demonstrates the law of multiple proportions?

Two elements $X$ and $Y$ have atomic weights of $14$ and $16$. They form a series of compounds $A, B, C, D$ and $E$ in which for the same amount of element $X$,the amounts of $Y$ are present in the ratio $1 : 2 : 3 : 4 : 5$. If the compound $A$ has $28$ parts by weight of $X$ and $16$ parts by weight of $Y$,then the compound $C$ will have $28$ parts by weight of $X$ and:

If element $A$ combines with element $B$ in a ratio of $1:2$ by mass,and element $A$ combines with element $C$ in a ratio of $6:4$ by mass,then by which law do elements $B$ and $C$ combine with each other?