"Alkanes must be vaporised before they will burn" - what does this mean? What does this sentence mean - I assumed that burning vaporised something? If something is vaporised, isn't that turning it into a gas? How can you burn a gas? This is a sentence in my AS Chemistry book and I am obviously missing something.

"Alkanes must be vaporised before they will burn"
Burning an alkane means reacting it with oxygen (in air). The larger the contact surface between the alkane phase and the air, the better the reaction. That's why cars have carburators: there's no larger "contact surface" than between the molecules in a gas mixture.