posted by Alicia .
I have a problem that states:
Find the pressure of a sample of carbon tetrachloride, CCl4 if 1.00 mol occupies 35.0L at 77.0 degress C (slightly above its normal boiling point). Assume that CCl4 obeys (a) the ideal gas law; (b) the van der Waals equation. The van der Waals constants for CCl4 are a= 20.39(L^2)(atm)/mol^2 and b= 0.1383L/mol.
I tried to do the problems and the answers I got are (a)=.814atm and (b)=.800atm but the back of the book is telling me that (a)=0.821atm an (b)=0.805. I'm not sure if i'm wrong or if the book is off.
Let's do the ideal gas law one.
P = nRT/V
n = 1 mole
T = 77.0 + 273.2 = 350.2 K
V = 35.0 L
R = 0.08206 L atm/mole K
P = 0.821 atm
It looks like the book is right. I suspect that you may be using the wrong value for R or are not carrying enough significant figures. Try it again with the van der Waals equation. If you don't recall it, use the second equation at
how to find the percent difference?