Question

calculate the mass of volume of a solution co taning 5g of glucose and 95g of water what is mass of glucose in 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