Q28 of 49 Page 22

Cinnabar (HgS) is a prominent ore of mercury. How many grams of mercury are present in 225 g of pure HgS? Molar mass of Hg and S are

200.6 g mol–1 and 32 g mol–1 respectively.

Molar mass of HgS = The molar mass of Hg + the molar mass of S

= 200.6 + 32 = 232.6 g mol–1


1molecule of HgS contains 1 atom of Hg


232.6 g of HgS contains 200.6 g of Hg


Therefore, Mass of Hg in 225 g of HgS =


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