Volcanoes spew off hydrogen sulfide, a poisonous, bad-smelling gas. A \(100.00-\mathrm{g}\) sample of hydrogen sulfide gas was obtained from some strange volcanic planet. Analysis showed that \(94.08 \mathrm{~g}\) 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 \(\mathrm{S}\) and \(\mathrm{H}\) as hydrogen sulfide from the strange volcanic planet. Which law accounts for this?

To find the mass of hydrogen in this \(100.00-\mathrm{g}\) sample of hydrogen sulfide, simply subtract the mass of sulfur from the total mass of the sample: Mass of hydrogen = Total mass of sample - Mass of sulfur = \(100.00 \mathrm{~g} - 94.08 \mathrm{~g}\).

To find the percentages by mass of sulfur and hydrogen, we'll divide the mass of each element by the total mass of the sample, and then multiply by 100. Percentage by mass of sulfur = (Mass of sulfur / Total mass of sample) × 100 Percentage by mass of hydrogen = (Mass of hydrogen / Total mass of sample) × 100

After calculating the percentages by mass of sulfur and hydrogen, we'll identify the law that accounts for the fact that hydrogen sulfide from Earth has the same percent compositions for S and H as hydrogen sulfide from the strange volcanic planet. Now, let's perform the calculations: Step 1: Calculate the mass of hydrogen in the sample Mass of hydrogen = \(100.00 \mathrm{~g} - 94.08 \mathrm{~g} = 5.92 \mathrm{~g}\) Step 2: Compute the percentages by mass of sulfur and hydrogen Percentage by mass of sulfur = \(\frac{94.08 \mathrm{~g}}{100.00 \mathrm{~g}} \times 100 = 94.08\%\) Percentage by mass of hydrogen = \(\frac{5.92 \mathrm{~g}}{100.00 \mathrm{~g}} \times 100 = 5.92\%\) Step 3: Identify the law that accounts for the same percent compositions The law that accounts for the fact that hydrogen sulfide from Earth has the same percent compositions for S and H as hydrogen sulfide from the strange volcanic planet is the Law of Definite Proportions (or Law of Constant Composition). This law states that a given compound always contains exactly the same proportion of elements by mass.