Question

Calculate the % composition of each element present in monosodium phosphate. Na = , H = , P = and O = .

Answer 1

Molecular formula = $Na{H}_{2}P{O}_4$
Molecular mass = $23+(2\times 1)+31+(4\times 16)=120\text{amu}$
% composition of $Na=\left(23/120\right)\times 100=19.17\%$
% composition of $H=\left(2/120\right)\times 100=1.67\%$
% composition of $P=\left(31/120\right)\times 100=25.83\%$
% composition of $O=\left(64/120\right)\times 100=53.33\%$