A sample of gas contains 0.2000 mol of C2H4(g) and 0.2000 mol of Br2(g) and occupies a volume of 13.7 L. The following reaction takes place:
C2H4(g) + Br2(g) CH2BrCH2Br(g)
Calculate the volume of the sample after the reaction takes place, assuming that the temperature and the pressure remain constant.