What is the percent composition of H_2S?

1 Answer
Apr 2, 2016

5.92% H, 94.08% S

Explanation:

Total mass of a compound is found by adding up the mass of all the atoms. Using mass numbers from the RSC periodic table, the total mass of the compound H_2S is

2 * 1.008gmol^-1 + 1 * 32.06gmol^-1 = 34.076gmol^-1

Percentage mass of an element in a compound is given by

M_e/M_t * 100%

where M_e is the mass of all the atoms of the element and M_t is the total mass of the compound.

Percentage mass of hydrogen therefore is

(2.016gmol^-1)/(34.076gmol^-1) * 100% = 5.92%

And, likewise, percentage mass of sulfur is

(32.06gmol^-1)/(34.076gmol^-1) * 100% = 94.08%