Whats the answer to the following

Question

Calculate the percentage composition of the following:

A. HgO

B Na2S

Answer 1

HgO:

Hg atomic wt = 201

O atomic mass = 16

molar mass = 217

% Hg = 201/217 (x100%) = 93%

% O = 100-93 = 7.0

Na₂S:

do the same way as above.

Na = 23 x 2 = 46

S = 32

molar mass = 78

%Na = 46/78 (x100%) = 59%

%S = 100-59 = 41%

These values are given to 2 significant figures.