What is the number of moles in 500L of He gas at STP

Ah, this is actually a fairly simple chemistry question.

Recall that at STP, one mole is equivalent to 22.4 L. Knowing this, all you have to do is divide 500 L by 22.4 L to find the number of moles:

500/22.4 = 22.3 mol

-T. B.