Calculate the volume V of hydrogen that can be added to ethylene V = 3L

C2H4 + H2 = C2H6

Let’s calculate the amount of ethylene substance under normal conditions (0 ° C, 1 atmosphere).

n (C2H4) = V / Vm = 3 / 22.4 = 0.134 mol

According to the reaction equation, 1 mole of hydrogen interacts with 1 mole of ethylene, which means that 0.134 mole of hydrogen will interact with 0.134 moles of ethylene.

n (H2) = 0.134 mol

V (H2) = n * Vm = 0.134 * 22.4 = 3 liters.

In the case of solid or liquid substances, the mass must be converted to the amount of the substance. Since the molar volume Vm of different gases is the same, it makes no sense to go over to the amount of matter.