A is the same as B. Pronoun?

[peteryoung]

Thanks for viewing this thread.

In order for a balloon to float in air, its weight must be the same as the weight of an amount of air having the same volume as the balloon.

Is 'same' here an pronoun or an adjective? And is the 'as' immediately after it a preposition, meaning 'like'?

Thank you very much!

[Casiopea]

"the" is a clue. Only nouns take it.

In the context you provided, 'same' functions as a (pro)noun.

[peteryoung]

Thanks!