Answer:
Explanation:
molar volume at STP=22.4 L
given volume=50.0 L
number of moles=given volume/molar volume
number of moles=50.0/22.4
number of moles=2.2
1 mole of helium =6.023*10^23 atoms
2.2 moles of helium =6.023*10^23*2.2=1.3*10^24
therefore 50.0 L of helium contain 1.33*10^24 atoms
