I read on the textbook a sentence like this:

Question

"The melting and boiling points of alkanes increase as their molecular sizes increase. This is because as alkane molecules become bigger, the attractive forces between the alkane molecules become stronger."

Please tell me if my understanding of that is wrong!

So, are they trying to say that as the molecular size of alkanes increase, the molecular mass also increases. When the size of alkane molecules become bigger, the attractive forces, or the intermolecular forces (van der Waals force) between alkane molecules increase, and hence a greater amount of thermal energy is needed to overcome this stronger van der waals forces. Hence an increased melting and boiling point. Is my understanding about the intermolecular force parts correct?

Please help, thanks!