Physical Properties of Alkanes

Physical Properties of Alkanes 1. alkanes are insoluble in water Alkanes that are liquid are less dense and float on water Alkane molecules are nonpolar; water molecules are polar

2. alkanes have lower boiling points than other organic compounds of similar size and weight The greater the molecular surface area, the greater the attractive forces between molecules Boiling point increases as the number of carbons in the molecule increases Boiling point decreases as branching increases

To determine boiling point: 1. look at the molecular formula 2. draw the structure 3. determine the order of boiling points