What property is associated with larger hydrocarbons compared to smaller ones?

Larger hydrocarbons exhibit higher boiling points compared to smaller hydrocarbons due to an increase in molecular size and mass. As the number of carbon atoms in a hydrocarbon increases, the number of electrons also increases, which boosts the overall van der Waals forces — the weak intermolecular attractions that arise from temporary dipoles in molecules. Consequently, more energy (in the form of heat) is needed to overcome these intermolecular forces, resulting in a higher boiling point for larger hydrocarbons.

For smaller hydrocarbons, the intermolecular forces are weaker due to their smaller size and lower surface area, meaning that less energy is required for them to change from liquid to gas. Thus, the trend in boiling points is a direct result of the molecular size and the associated increase in van der Waals forces with larger hydrocarbons.