Let the density of solution = d g/cm3
and volume of solution is = 1L = 1000 cm3
mass of the solution = d xV
6.90 M solution mean 1L solution contains 6.90 moles of KOH
therefore mass of KOH = 6.90 x 56 = 386.4g
but only 30% of the solutionby mass is KOH
30/100 x (1000)d =386.4
and density is 1.288g/ cm3
Calculate (a) molality (b) molarity and (c) mole fraction of KI if the density of 20% (mass/mass) aqueous KI is 1.202 g mL-1.
Calculate the mole fraction of benzene in solution containing 30% by mass in carbon tetrachloride.
Let the total mass of the solution be 100g and mass of benzene be 30 g
therefore mass of tetrachloride= (100-30)g = 70g
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: