Vapoure pressure of pure water (solvent) at 298 K, p0 = 23.8 mm
Vapour pressure of solution, p = ?
Mass of solvent ,W = 850 g
Mass of solute,M = 50 g
Mol. mass of water (H2O), M = 18 g mol–1
Mol.mass of urea NH2 CO NH2
= 14 + 2 + 12 + 16 + 14 + 2
= 60 g mol–1
According to Raoult's law,
Hence, 23.78 mm Hg. Ans.
Calculate the mole fraction of benzene in solution containing 30% by mass in carbon tetrachloride.
Molar mass of benzene,
Molarity (M) is defined as number of moles of solute dissolved in one litre (or one cubic decimetre) of solution.
(a) Mol. mass of
Volume of solution = 4.3 L
(b) Number of moles present in 1000 ml of 0.5M H2SO4= 0.5 mol
therefore number of moles present in 30ml of 0.5M H2SO4=mol =0.015mol
therefore molarity =0.015/0.5L
thus molarity is 0.03M
Molality (m) is defined as the number of moles of the solute per kilogram (kg) of the solvent and is expressed as: