After 0.600 L of Ar at 1.40 atm and 210 "^oC is mixed with 0.200L of O_2 at 398 torr and 120 "^oC in a 400 -mL flask at 29 "^oC, what is the pressure in the flask?

1 Answer
Jul 2, 2018

Well, FIRST off we calculate the molar quantities of each gas...by means of the Ideal Gas equation...

n=(PV)/(RT)...

Explanation:

n_"Ar"=(1.40*atmxx0.600*L)/(0.0821*(L*atm)/(K*mol)xx483.15*K)=0.0212*mol

n_(O_2)=((398*mm)/(760*mm*Hg*atm^-1)xx0.200*L)/(0.0821*(L*atm)/(K*mol)xx393.15*K)=0.00325*mol

And now we ADD these molar quantities, and calculate the pressure expressed under the NEW given conditions...

P_"mixture"=(0.245*molxx0.0821*(L*atm)/(K*mol)xx302.15*K)/(400*mLxx10^-3*L*mL^-1)

I make this approx. 15*atm but do not trust my arithmetic...and there is a lot of rithmetick here...