Van der Waals Questions/Need help

Chemistry and homework help forum.

Organic Chemistry, Analytical Chemistry, Biochemistry, Physical Chemistry, Computational Chemistry, Theoretical Chemistry, High School Chemistry, Colledge Chemistry and University Chemistry Forum.

Share your chemistry ideas, discuss chemical problems, ask for help with scientific chemistry questions, inspire others by your chemistry vision!

Please feel free to start a scientific chemistry discussion here!

Discuss chemistry homework problems with experts!

Ask for help with chemical questions and help others with your chemistry knowledge!

Moderators: Xen, expert, ChenBeier

Post Reply
ricog
Newbie
Newbie
Posts: 1
Joined: Thu Jun 08, 2017 4:11 pm

Van der Waals Questions/Need help

Post by ricog »

Hello!

I am using the van der waals calculator to check my calculations but I seem to be getting very different numbers and im not sure why.

I am using this equation (P + a(n/v)^2)(v-nb) = nRT

My units are pressure in atm, volume in Liters and temp in kelvin. Im using R as atm L mol-1 k-1 . I am trying to isolate to solve for moles in a given container.

My Pressure is 3600 psi ~ 244.9655 atm
My internal volume is 41.9 L
My temperature is 294.2611111 K
The gas i am correcting for is oxygen.. My a is 1.362652 atm L^2 mol^-2 and my b is 0.03186 L/mol.

Calculating this out and solving for n i get 462.324 moles however the webqc calculator gives me 321.458....

I'm not sure if I am running into a conversion error or a simple mathematical error but if anyone could help that would be awesome!
Post Reply