Question

What is the volume of 1.2 moles of oxygen gas at STP?

Answer 1

At STP, 1.2 moles of `O_2` has a volume of 27 L.

Explanation:

Since we are at STP and are given only one set of conditions, we have to use the ideal gas law equation:

I should mention that the pressure does not always have units of atm, it depends on the units of pressure given in the gas constant.

List your known and unknown variables. Our only unknown is the volume of `O_2(g)`. Our known variables are P,n,R, and T.

At STP, the temperature is 273K and the pressure is 1 atm.

Now we have to rearrange the equation to solve for V:

`(nxxRxxT)/P`

`V = (1.2 cancel"mol"xx0.0821Lxxcancel(atm)/cancel(molxxK)xx273cancelK)/(1cancel(atm)`

`V = 27 L`