$0.765 \ g$ of an acid gives $0.535 \ g$ of $CO_2$ and $0.13 \ g$ of $H_2O$. The ratio of the percentage of $C$ and $H$ is:

The empirical formula of a compound is $C_2H_5O$ and its vapour density is $45$. What is the molecular formula of the compound?

What is the percentage by mass of oxygen in $NaOH$? (Atomic mass of $Na=23 \ u, O=16 \ u, H=1 \ u$)

Determine the empirical formula of an oxide of iron which has $69.9 \%$ iron and $30.1 \%$ dioxygen by mass.

An organic compound has $C = 60\%$,$H = 13.3\%$ and $O = 26.7\%$. Its empirical formula will be

$1.25 \ g$ of a metal $(M)$ reacts with oxygen completely to produce $1.68 \ g$ of metal oxide. The empirical formula of the metal oxide is
[molar mass of $M$ and $O$ are $69.7 \ g \ mol^{-1}$ and $16.0 \ g \ mol^{-1}$,respectively]