Volcanoes spew off hydrogen sulfide, a poisonous, bad-smelling gas. A 100.00-g sample of hydrogen sulfide gas was obtained from some strange volcanic planet. Analysis showed that 94.08 g of it is the element sulfur. The rest of the sample consists of the element hydrogen.

(a) What are the percentages by mass of sulfur and hydrogen in this sample?

(b) Hydrogen sulfide from Earth has exactly the same percent compositions for S and H as hydrogen sulfide from the strange volcanic planet. Which law accounts for this?