A 4.44 L container holds 15.4 g of oxygen at 22.55°C. What is the pressure?

1 Answer
Jun 18, 2017

We use the Ideal Gas Equation to get...........P=2.63atm

Explanation:

P=nRTV=15.4g32.00gmol1×0.0821LatmKmol×295.7K4.44L=

2.63atm.

Do the units cancel out to give an answer in atm? Do they? Don't assume that I haven't made a mistake!

How did I do this? Well for (i) I know that oxygen is a binuclear gas, i.e. O2; in fact all the elemental gases (save for the Noble Gases) are BINUCLEAR.....and thus I used a molecular mass of 32.00gmol1 for dioxygen gas.......

And (ii) I knew the gas constant was............... 0.0821LatmK1mol1.

And (iii) I knew the relationship between C and degrees Kelvin.

These data (well (ii) and (iii)) need not be remembered, as they should be provided (with various units) in a chemistry exam. You still need to know how to use the appropriate gas constant, R.