Variable
benzene
ethylbenzene
2-methylpropane
n-pentane
2-2-dimethylbutane
isoprene
3-methylpentane
o-xylene
propane
ethane
n-butane
n-octane
propene
m-p-xylene
2-methylpentane
2-2-4-trimethylpentane
n-heptane
cyclo-hexane
toluene
n-hexane
ethene
2-methylbutane
1-butene
cis-2-butene
2-2-dimethylpropane
2-methylhexane