Question

Hydrogen sulfide gas (H2S) is a highly toxic gas that is responsible for the smell of rotten eggs. The volume of a container of hydrogen sulfide is 44.2mL. After the addition of more hydrogen sulfide, the volume increases to 98.5mL under constant pressure and temperature. The container now holds 1.97×10−3mol of the gas. How many grams of hydrogen sulfide were in the container initially? Give your answer in three significant figures.

Answer 1

`\boxed{\text{0.0301 g}}`

Step-by-step explanation:

1. Calculate the initial moles of H₂S

We can use Avogadro's law: the number of moles of a gas is directly proportional to the volume if the pressure and temperature are constant.

`(n_(1) )/(V_(1)) = (n_(2))/(V_(2))\\\\\frac{n_(1)}{\text{44.2 mL}} = \frac{1.97 * 10^(-3) \text{ mol}}{\text{98.5 mL }}\\\\(n_(1))/(44.2) = 2.00 * 10^(-5) \text{ mol}\\\\n_(1) = 44.2 * 2.00 * 10^(-5) \text{ mol} = 8.84 * 10^(-4) \text{ mol}`

2. Calculate the initial mass of H₂S

`\text{Mass of H$_(2)$S} = 8.84 * 10^(-4)\text{ mol H$_(2)$S} * \frac{\text{34.08 g H$_(2)$S}}{\text{1 mol H$_(2)$S}} = \text{0.0301 g H$_(2)$S}\\\\\text{The container initially held }\boxed{\textbf{0.0301 g H$_(2)$S}}`