$10 \, g$ of $CaCO_3$ contains

Chlorine exists in two isotopic forms $^{35}Cl$ and $^{37}Cl$. If the average atomic mass of chlorine is $35.5$,what is the percentage abundance of these isotopes respectively?

Among $10^{-9} \ g$ (each) of the following elements,which one will have the highest number of atoms?
Element: $Pb, Po, Pr$ and $Pt$

In $1 \ g$ of a metal oxide,the mass of metal precipitated is $0.68 \ g$. What is the equivalent weight of the metal?

If we consider that $1/6$ of the mass of a carbon atom,in place of $1/12$,is taken to be the relative atomic mass unit,the mass of one mole of a substance will

Statement $1$: The equivalent mass of $Cu$ in $CuO$ is $63.6$ and in $Cu_2O$ is $31.8$. Statement $2$: Equivalent mass = $\frac{\text{Molecular mass}}{\text{Valency}}$