C2H4(g) + H2(g)C2H6(g)

Question

A sample of gas contains 0.1100 mol of C₂H₄(g) and 0.1100 mol of H₂(g) and occupies a volume of 10.1 L. The following reaction takes place:

C₂H₄(g) + H₂(g)C₂H₆(g)

Calculate the volume of the sample after the reaction takes place, assuming that the temperature and the pressure remain constant.

Answer 1

Avogadro's Law states that if the temperature and pressure are constant, the volume is proportional to the number of moles of an ideal gas. Put another way, V1/n1 = V2/n2

V1 = initial volume = 10.1 L

n1 = initial number of moles of gas = 0.11 mol C2H4 + 0.11 mol H2 = 0.22 moles of gas

V2 = final volume = ?

n2 = final number of moles of gas = 0.11 moles of C2H6

10.1 L/0.22 mol = V2/0.11 mol

V2 = 5.05 L