A solution of potassium nitrate in water

Question

has a freezing point of -0.082◦C. What is
the concentration of KNO3 in this solution?
Kf = 1.86 ◦C/m for water.

Answer 1

moles/kgwater=.082/1.86

massKNO3/(molmass*kgwater)=.082/1.86
masskno3/kgwater= .082*molmass/1.86= concentration.
you can change that to percent w/w if you wish.