Nickel steel is an alloy that typically contains $3-5 \%$ of nickel $(Ni)$. What is the minimum percentage of nickel present in this alloy (in $\%$)?

The empirical formula of an acid is $CH_2O_2$. The probable molecular formula of the acid may be:

In a substance,the number of atoms of $Cr$ and $O$ are $4.8 \times 10^{10}$ and $9.6 \times 10^{10}$ respectively. The empirical formula of the substance is .......

Find the empirical formula of the compound if $M = 68 \%$ (Atomic mass $= 34$) and the remaining $32 \%$ is oxygen:

By combustion of $0.2475 \ g$ of an organic compound,$0.4950 \ g$ of $CO_2$ and $0.2025 \ g$ of $H_2O$ are obtained. Calculate the percentage of $C, H,$ and $O$. Given atomic masses: $C = 12, H = 1, O = 16$.

If two compounds have the same empirical formula but different molecular formulae,they must have: