Question

can anyone explain to me about the Van Der Waals equation and its coefficients (a and b). Thanks a lot!

Answer 1

Van der Waals equation is an attempt to modify the ideal gas equation PV=nRT to take into account two factors that are different from the definition of an ideal gas.

Answer 2

Can you please clarify about the coefficients?

Answer 3

you want the meaning for coefficients

Answer 4

hello

Answer 5

yes sorry, I didn't understand it at all

Answer 6

Example: 6z means 6 times z, and "z" is a variable, so 6 is a coefficient. Sometimes a letter stands in for the number. Example: In ax2 + bx + c, "x" is a variable, and "a" and "b" are coefficients.

Answer 7

Van der Waals equation is an attempt to modify the ideal gas equation PV=nRT to take into account two factors that are different from the definition of an ideal gas.

1) There is some interaction between molecules so they will exert less pressure on the container
2) The molecules do take up some volume.

We therefore get (P + a/V^2) to alter the pressure and (v-b) to reduce the total volume

Thus a large molecule will have a high value of 'b' as it takes up more space.
A large molecule will also have more interaction between it and other molecules (Van der Waals forces increase with molecular size generally)
Thus Propane should have the largest 'b' value

(If interested: for propane a= 8.779 and b = 0.08445 and toluene (for comparison a much bigger molecule) 24.38 0.1463 respectively

Answer 8

Thanks for the detailed explanation!