Two liquids A and B have vapor pressures of 71.3 and 131 mmHg, respectively, at 25 degrees Celsius. What is the total vapor pressure of the ideal solution made up in the following concentrations?

Question

1.00 mole of A and 1.00 mole of B

2.00 moles of A and 5.00 moles of B

Answer 1

1 mol A + 1 mol B = 2 mols total.
X_A = nA/nTOTAL = 1/2
X_B = nB/nTOTAL = 1/2
P_A = X_A*P^o_A

P_B = X_B*P^o_B
Total P = P_A + P_B