Why does Hydrogen sulfide have a greater gas density than air (by 18%)?

Answer 1

Hydrogen sulfide is 18% heavier than air because its molecular weight is 18% larger.

Hydrogen sulfide (H2S) has a higher molecular weight (34.1) than the molecular weight (28.8) of air which is mostly (80% N2 + 20% O2.)

34.1 / 28.8=1.184
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