Calculate the molality of aq. glucose solution in which mole fraction of glucose is 0.05

Asked by Anil | 12th May, 2017, 09:37: PM

Expert Answer:

molality = (number of moles of solute/(kg of solvent)
 
If we have 0.05 mole of glucose solute and 0.95 mole of water, going off of the mole fractions.
 
1 mole of water = 18.015 g.
 
Hence ,0.95 moles of water has a mass of (0.95)(18.015 g)(1kg / 1000 g) = 0.01711 kg.
 
 
molality = 0.05 moles glucose / 0.01711 kg water = 2.92 mol/kg

Answered by Vaibhav Chavan | 13th May, 2017, 06:00: PM