:confused: how would I find the volume of the following masses of gases at STP
80 grams O2
10 grams H2
14 grams N2
66 grams CO2
Can please some one explain me how to do it

Ideal Gas Law:


you can work out n, R is constant, T and P are given, V is all that's left and is what you want :)

Ask if you need further help :)

Agreed -- and you can shorten the amount of repetitive work you have to do by calculating the volume of 1 mol of a gas at STP. The number you get is the volume per mol of any gas that's at STP -- so if you do that calculation once (watch your units and perhaps convert the volume unit into something useful like cc or liters), then you'll only have to convert all your given gases (which are all at STP) from grams to moles, and then use the number you calculated above to convert from moles to volume.

Note: if you've never seen PV=nRT before, you were probably given the conversion between volume and moles as just a numerical constant (maybe in units of L/mol?). I would state what it is but that might be too close to doing the problem for you (not sure).

Yes, good call vrooje, the OP can always ask if he needs help with mass/mole conversion :)

That's why I left it out - as well as the definition of STP