Calculate the molar mass amount of substance volume and number of molecules: m (H2S) = 17 g.

1 The molar mass of a substance is numerically equal to the relative molecular mass of a substance.
M (H2S) = Mr (H2S) = 2 + 32 = 34 g / mol
2. To find the volume of 17 g of hydrogen sulphide, you need to calculate its amount, i.e. the mass of the substance must be divided by the molar mass.
n = m / M
n = 17g / 34g / mol = 0.5 mol
3. Then, knowing that the molar volume of any gas is 22.4 l / mol, we can find out the volume of 0.5 mol
V = 0.5 mol * 22.4 l / mol – 11.2 l
4.1 mol contains 6 * 10 (23 degrees) molecules, then:
N = 0.5 * 6 * 10 (23) = 3 * 10 (23) molecules.