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Q.
The percentage of nitrogen by mass in ammonium sulphate is closest to (atomic masses of $H =1, N =14$, $O =16, S =32$ )
KVPYKVPY 2015
Solution:
Total mass of ammonium sulphate $\left( NH _{4}\right)_{2} SO _{4}$
$=2 \times 18+32+16 \times 4$
$=36+96=132$
Mass of nitrogen in $\left( NH _{4}\right)_{2} SO _{4}=28$
$\%$ of $N$ by mass in $\left( NH _{4}\right)_{2} SO _{4}=\frac{28}{132} \times 100$
$=21.2 \%$