How many molecules are in 30 liters of methane #CH_4# at STP?
Moles x Avogadro's number.
Pv=nrt is the equation to use, and as we have the excercise already giving us STP we can calculate it as we know that temperature is 273 Kelvin and Pressure is 100000 Pa. We want to find n so let's make it the subject of our formula.
The calculation becomes=
0.03 Is our volume because 30 liters is the same as
So then the amount of molecules is equal to that number times Avogadro's number.