Question

How many molecules are there in 77.6 L of helium at STP?

Answer 1

`(22.4"L "H)/(1"mol "H)=(77.6"L "H)/(x"mol "H)`

`x=3.46"mol "H`

`3.46"mol "Hxx(6.022xx10^(23)"molecules "H)/(1"mol "H)=2.09xx10^(24)"molecules "H`