What is the percentage of carbon in urea (in $\%$)? $(At. mass C = 12, H = 1, N = 14, O = 16)$

The molecular formula of the chloride of a metal $M$ is $MCl_3$. The formula of its carbonate would be:

The sulphate of a metal $M$ contains $9.87\%$ of $M$. This sulphate is isomorphous with $ZnSO_4 \cdot 7H_2O$. The atomic weight of $M$ is (in $.3$)

How much copper can be obtained from $100 \, g$ of copper sulphate $(CuSO_{4})$?

$A$ compound of carbon,hydrogen,and nitrogen contains three elements in the respective ratio of $9 : 1 : 3.5$ grams. The empirical formula for the compound is

$A$ gaseous compound of nitrogen and hydrogen contains $12.5\%$ (by mass) of hydrogen. The density of the compound relative to hydrogen is $16$. The molecular formula of the compound is