The oxide of a metal contains $40 \%$ of oxygen. The valency of the metal is $2$. What is the atomic weight of the metal?

The equivalent weight of a divalent metal is $32.7$. The molecular weight of its chloride is .....

The relative abundances of two isotopes of rubidium with atomic masses $85$ and $87$ are $75\%$ and $25\%$ respectively. What is the average atomic mass of rubidium (in $.5$)?

In chlorine gas,the ratio of $Cl^{35}$ and $Cl^{37}$ is

The equivalent mass of a certain bivalent metal is $20$. The molecular mass of its anhydrous chloride is

When the weights of two elements combine with each other,their ratio is the ratio of their ......