How many atoms are present in one cc of helium gas at STP?

Explanation

At STP, 22400 cc `=6.022 xx 10^(23)` atoms
At STP, one cc=?
Number of atoms present in one cc at STP
`=(6.022 xx 10^(23))/(2.24 xx 10^(4))=2.69 xx 10^(19)`