Final answer:
Alkanes with one to four carbon atoms exist as gases at room temperature, while alkanes with more than four carbon atoms exist as liquids or solids. The intermolecular forces of attraction between molecules of alkanes are weak dispersion forces.
Step-by-step explanation:
Alkanes are nonpolar molecules that exist primarily as gases at room temperature, with alkanes containing one to four carbon atoms in the gas state. However, alkanes with more than four carbon atoms are either liquids (methanol, for example) or solids (larger alkanes). The intermolecular forces of attraction between molecules of alkanes are weak dispersion forces, also known as London forces.