Posted by Gweedo8 on Thursday, June 18, 2009 at 2:15pm.
(L2bar/mol2) (L/mol)
Acetylene 4.448 0.05136
Calculate the difference in pressure (in atm) when 100.0g of acetylene acts as an ideal gas versus as a real gas in a 100L tank at a temperature of 1000K.
1) Change 100.0g C2H2 to moles (n)
2) Calculate the ideal pressure using the Ideal Gas Law:
PV = nRT, P = nRT/V
3) Calculate the real pressure using the Van der Waals Equation. You can find the equation here:
http://hyperphysics.phy-astr.gsu.edu/Hbase/Kinetic/waal.html
Constants "a" and "b" for acetylene can be found here:
http://en.wikipedia.org/wiki/Van_der_Waals_constants_(data_page)
The difference between P(ideal) and P(real) can be found by subtracting the smaller from the larger one.
[Be prepared to spend some time on this problem]
HERE IS MY HOMEWORK:
I have been trying the real gases homework for hours and am completely stuck. This is what I have been attempting to make work. First I found the moles then plugged in all the other variables.
100gC2H2/26.0373g/mol=3.84mol C2H2=n
P=nRT/(V-nb)-an^2/V^2
P= n R T /(V - n b) - a n^2 / V^2
319.49=3.84x8.3145x1000/(100-3.84x.05136)-4.39x3.84^2/100^2
319.49 is not the correct answer and I have only confused myself further and further trying to understand this. At this point I am just pushing buttons on my calculator hoping for a miracle. Please release me from my torture:)