Question

one litre of 1.2 molar solution of glucose weights 1350g. what is the molarity of the solution?​

Answer 1

10%w/w solution of glucose in water means 10 g of glucose present in 100g of solution. Therefore, Mass of glucose is 10g Mass of water is = 100g- 10g = 90 g = 0.09 kg And density = 1.2gmL-1 Let us find molality Molality = Number of moles of solute / Mass of solvent in Kg Number of moles of solute = Mass of glucose / Molar mass of glucose Molar mass of glucose (C6H12O6) = 6x12 + 12x1 + 6x16 =180 g /mol Number of moles of glucose = 10/180 = 0.0556 moles Molality = 0.0556/0.09 = 16.7M Now find the molarity , Molarity = Number of moles of solute / Volume of solution in liter Density = 1.2 g/ml Volume = mass / density = 100 g / 1.2 g/ ml = 83.33 ml = 0.0833 L Molarity = 0.0556/ 0.0833 = 0.67 M