Butane and 2-methylpropane are both nonpolar and have the same . . .?

Question

molecular formula, yet butane has the higher boiling point (-0.5°C compared to -11.7°C). Explain.

Please help. I am not good with Chemistry.

Answer 1

Butane is quite different from 2-methyl propane,Butane has 4 carbon in the chain while 2-methyl propane has 3 carbon as the parent chain and the alkyl sidechain which is methyl & is attached to the 2nd carbon of the parent chain..

non polar compounds usually has higher BP because its interaction between the atoms is strong,i mean their bond is too hard to break making its system more stable and more energy is required for it to disrupt/disconnect..(heat is required,longer duration of heating to determine its BP)

as the carbon increase from methane,ethane-...octane and so on the more difficult to break its bond

the reason why butane has higher BP,in my opinion this is because it is stable and  no sidechain is in contact whereas from 2 methyl propane w/c has a methyl sidechain that'll be disrupt first and eventually disturbed the chain when methyl is disconnected making the parent chain unsaturated..

though somewhat they're the same having 4 carbons.,chemically they are not the same propane has 3 whilst butane has 4.,in 2 methyl propane the H in the 2nd carbon is replaced by an alkyl group.it does not necessarily mean that their boiling will be equal.

Answer 2

2-methylpropane is not a straight chain alkane, while n-butane is. Branched chain alkanes generally have higher boiling points due to their surface area being greater than linear chains, which causes stronger van der Waals forces. In order to disrupt the stronger van der Waals force, you need to put more energy into the system.