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

In a copper sulfate solution,$3.2 \ g$ of copper is displaced by $2.8 \ g$ of iron. If the equivalent mass of iron is $28$,what is the equivalent mass of copper?

An element has two main isotopes of mass numbers $85$ and $87$. In nature,they occur in the ratio of $75\%$ and $25\%$ respectively. The atomic weight of the element will be approximately:

$0.126 \ g$ of an acid is needed to completely neutralise $20 \ mL$ of $0.1 \ N$ $NaOH$ solution. The equivalent weight of the acid is:

Oxygen contains $90\%$ of $^{16}O$ and $10\%$ of $^{18}O$. Its atomic mass is

If a metal oxide contains $32\%$ oxygen,what is the equivalent mass of the metal?