its boiling point. This is due to the long hydrocarbons being able to wrap around each other. It takes more energy to shake them apart to allow them to evapourate into a gas, hence the required higher temperature. The wrapping around of chains also affects the viscosity of the fraction. The longer the chain the longer it takes to pour the liquid.
Flammability is how easily something will burn or ignite. Small hydrocarbon chains have a higher degree of flammability - they are more flammable because they have a higher proportions of carbon-hydrogen bonds compared to carbon-carbon bonds, for the same number atoms. Carbon-hydrogen bonds are easier to break than carbon-carbon bonds and so short chains are easier to start the chemical reaction of combustion.
