y owLx2 1 Online te and owcom im tak eAssignment takeCovale

× y owLx2 1 Online te and owcom im tak eAssignment takeCovalentActivity do? ocator= assignment take&takeAssignmentSessionLocator;=assignment take CHEMWORK A solution is made by dissolving 48.9 g urea (CHN,0), a nonelectrolyte, in 275 g water. Calculate the vapor pressure of 45°C. 25°C 23.8 torr 45°C 71.9 torr vapor pressure at 25°C vapor pressure at 45°C torr torr Previous Nexd

Solution

Answer

Vapour pressure at 25^°C = 22.6torr

Vapour pressure at 45°C = 68.3torr

Explanation

According to Raoult\'s law

P_solution = X_solvent × P°_solvent

_{No of moles of urea =48.9g/60.06g/mol = 0.8142}

_{No of moles of water = 275g/18.02g/mol = 15.2608}

_{Total no of moles = 0.8142 + 15.2608 = 16.075}

Mole fraction of water = 15.2608/16.075 = 0.9493

at 25°C, P°_solvent = 23.8torr

P_solution = 0.9493 × 23.8torr = 22.6torr

at 45°C, P°_solvent = 71.9torr

P_solution = 0.9493 × 71.9torr = 68.3torr