Question

Two liquids, A and B, have vapor pressures at a given temperature of 24
mmHg and 36 mmHg, respectively. We prepare solutions of A and B
at a given temperature and measure the total pressures above the solutions. We obtain the following data:
Solution Amount A (mole) amount b (mole) P (mmHg)
1 1 1 30
2 2 1 28
3 1 2 32
4 1 3 33

Predict the total pressure above a solution of 3 mol A and 3 mol B.

Answer 1

mols A = 3
mols B = 3
Total mols = 6
Xa = 3/6 = 0.5
Xb = 3/6 = 0.5
partial pressure A in mixture = Xa x P^oa
partial pressure B in mixtgure = Xb x P^ob
Ptotal = p of a + p of b.

Answer 2

Forgot to say that I have calculated it but you could look at the data and foer a 1:1 ratio (the mole fractions are 0.5 for each) and you measured 30 mm for Ptotal.