What is the mass fraction of mercury and oxygen in bivalent mercury oxide?

Given:
mercury (II) oxide – HgO

Find:
ω (Hg in HgO) -?

Solution:
1) Using the periodic system of D.I.Mendeleev, calculate the relative molecular weight of mercury (II) oxide:
Mr (HgO) = Ar (Hg) * N (Hg) + Ar (O) * N (O) = 201 * 1 + 16 * 1 = 217;
2) Calculate the mass fraction of mercury in mercury (II) oxide:
ω (Hg in HgO) = N (Hg in HgO) * Ar (Hg) * 100% / Mr (HgO) = 1 * 201 * 100% / 217 = 92.63%.

Answer: The mass fraction of mercury in mercury (II) oxide is 92.63%.