How would you set this problem up: How many hydrogen molecules are in 44.8L H2(g) at STP?

Answer 1

from memory, so check my results.

AT STP 1 mole of ANY gas occupies 22.4 liters. A mole is 6.02 times 10 to the 23 molecules.

so your answer should be
1.204 times 10 to the 24th Hydrogen molecules