Experiment results show that butane has a higher boiling point than propane, explain why.

When simple molecular substances such as a hydrocrabons are boiled, the intermolecular forces between the molecules are broken down. Heat energy is required to break down these forces. Butane is larger than propane and the larger a molecule is, the more intermolecular forces there are between those molecules. If there are more intermolecular forces between molecules, more energy is needed to break those bonds down, resulting in the larger chained hydrocarbons (butane in this case) having higher boiling points.