p*V=nRT =>n=p*V/R*T=2*1.64/0.082*400=3.28/32.8=0.1 moli H2
1mol........1mol
CnH2n + H2 ----> CnH2n+2
0.1 mol..........0.1mol
n=m/M =>M=m/n=7/0.1=70g/mol
14n=70 ==>n=5 ==>C5H10-->1-pentena, 2-pentena, izomerii cis si trans..2 metil 1 butena, 2 metil 2 butena