Avogadros Law Chemistry

Question

A sample of gas contains 0.120 mol of C₂H₄(g) and 0.120 mol of H₂O₂(g) and occupies a volume of 13.3 L. The following reaction takes place:

C₂H₄(g) + H₂O₂(g)CH₂OHCH₂OH(g)

Calculate the volume of the sample after the reaction takes place (assume temperature and pressure are constant).

Answer 1

From the balanced equation, we see that 1 mol of C2H4 reacts with 1 mol H2O2 to produce 1 mol CH2OHCH2OH. From this mol ratio, we can conclude that 0.120 mol of each gas will produce 0.120 mols of the product, CH2OHCH2OH. Thus, at constant pressure and constant temperature, only the volume will change and this will be dependent on the number of moles of gas that are present (Avogadro's Law).

n1 = initial number of moles of gas = 0.120 + 0.120 = 0.240 mols

n2 = final number of moles of gas = 0.120 mols

V1 = initial volume = 13.3 L

V2 = final volume = ?

Avogadro's Law:

V1/n1 = V2/n2

13.3 L / 0.240 mol = x L / 0.120 L

x = 6.65 L