The partial pressure at 25 °C of the water vapour above a water-ethanol solution for which x(H2O) = 0.5 is 3.7 kPa. The total vapour pressure is 8.7 kPa. For pure water at 25°C, p*(H2O) = 3.4 kPa; for pure ethanol p*(ethanol) = 4.3 kPa. Calculate the activity and activity coefficient of the water.
The pore size of membranes can be measured by using the decrease in vapour pressure of liquid nitrogen condensed in the pores (i.e. cavities) at low temperatures. Calculate the diameter of the pores in a membrane if at 80.0 K the pressure of N2 gas above the membrane is measured to be 1.310 bar. At […]