Question

solution of glucose in water is labelled as 20% by weight. what would be the molality of the solution of glucose is 180 gram mole inverse​

Answer 1

Answer:

Molality = number of moles of solute/mass of solvent in Kg ……(1)

Now we have to find number of moles and mass of solvent in Kg both

mass of solute = mass of glucose /molar mass of glucose …..(2)

Molar mass of glucose (C6H12O6) = 6×C + 12×H + 6×O

= 6×12 + 12×1 + 6×16

=180 gm /mol

Putting the value back in equation (2) we get

Number of moles = 20/180 = 0.111 moles

We have mass of solvent (H2O) = Mass of solution – Mass of solute

= (100g- 20)gm

= 80 gm

Mass in Kg = 80gm× 1 Kg / 1000 g = 0.08 Kg

Putting the value in equation (1) we get

Molality = 0.111/0.08 = 1.3875 M

Molality = 1.3875 M

Hope it helps! ! !