Chemistry - Individual Gas Laws

Question

If 17.5 mols of Ar gas occupies 141.8 L, how many mL would occupy 33.5 mol occupy under the same temperature and pressure?

Answer 1

Hi Julia,

We know this is at STP (Standard Temperature & Pressure), so we can absolutely disregard pressure and temperature. We can also disregard the gas constant R. All we have is the moles (n) and the volume (V).

One way I would suggest is that we have the same gas and we have a ratio of 17.5 mol occupies 141.8 L. How many mL would occupy 33.5 mol of the same gas? Just set up two ratios, have them equal to each other, find the volume in L, and then convert that to mL.

17.5 mol/141.8 L = 33.5 mol/x L <-- Our x represent the unknown volume for the second fraction.

Do cross multiplication:

(17.5 mol)(x L) = (141.8L)(33.5 mol) <-- Divide 17.5 mol on both sides.

(x L) = (141.8L)(33.5 mol)/(17.5 mol) <-- If you have to keep sig figs, the total sig figs needed would be 3

x = 271.4457143 L <-- Convert L to mL by multiplying our new volume by 1000, and then if you need to apply sig figs, you can do so afterward.

x = 271.4457143 L x (1000 mL)/(1 L) = 271445.7143 mL

Hope this helps, and if you would like more help, just reply back to this response.