$20$ carat gold contains ...... $(\%)$ percent gold.

An organic compound on analysis gives the following data: $C = 57.82 \%$,$H = 3.6 \%$ and the rest is oxygen. Its vapour density is $83$. Calculate its molecular formula.

$A$ gas is found to have a formula $[CO]_x$. If its vapour density is $70$,the value of $x$ is

Compound $A$ contains $8.7\,\%$ Hydrogen,$74\,\%$ Carbon and $17.3\,\%$ Nitrogen. The molecular formula of the compound is ....
Given : Atomic masses of $C$,$H$ and $N$ are $12$,$1$ and $14\, amu$ respectively.
The molar mass of the compound $A$ is $162\, g\, mol^{-1}$.

$60 \ g$ of a compound on analysis gave $C = 24 \ g$,$H = 4 \ g$ and $O = 32 \ g$. Its empirical formula is

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