3.2 and 3.3 I can recall the general formula and displayed formulae of alkanes

What is the general formula for alkanes?      CnH2n+2
Describe and explain the trend in boiling point: A straight-chain alkane will have a boiling point higher than a branched-chain alkane due to the greater surface area in contact and the mass of the alkane increase the boiling point increases

Draw the displayed formula of the three isomers of pentane: