The simplest formula of a compound containing $50\%$ of element $X$ (at. wt. $= 10$) and $50\%$ of element $Y$ (at. wt. $= 20$) is

The empirical formula of a crystalline iron compound is $Fe_2(SO_4)_3$. It is used in water and sewage treatment to remove suspended impurities. The percentage composition of iron,sulfur,and oxygen in this compound is respectively......

If two compounds have the same empirical formula but different molecular formulas,which of the following do they possess?

Among the following,the compound with the highest percentage of chlorine is:

The molecular formula of feldspar is

If the percentage of $Se$ (atomic weight $78.4$) in a peroxidase anhydrous enzyme is $0.5\%$,what is the minimum molecular weight of the peroxidase anhydrous enzyme?