Question

Question 28
Cinnabar (HgS) is a prominent ore of mercury. How many grams of mercury are present in 225 g of pure HgS? Molar mass Hg and S are $200.6gmo{l}^{-1}$ and $32gmo{l}^{-1}$ respectively.

Answer 1

Given,
Molar mass of Hg = $200.6gmo{l}^{-1}$
Molar mass ​​​​​​of ​S = $32gmo{l}^{-1}$
Molar mass of $\text{HgS}=200.6+32=232.6gmo{l}^{-1}$
Mass of Hg in $\text{232.6 g HgS}=200.6g$
Therefore, Mass of Hg in $225gof\text{HgS}=\frac{200.6}{232.6}\times 225=194.045g$