
Ellen E. answered 05/15/19
Chemistry Tutor - High School, AP, College
The formula for molality is :
moles of solute / kg of solvent
Sugar is the solute, and it has a formula weight of 342.3 g/mol
5.13 g of sugar is 0.0150 moles.
Water is the solvent. Without extra information, I'll assume a density of 1 g/ml.
Therefore 250 ml = 250 g = 0.25 kg
Molality is moles solute/kg of solvent, so 0.0150 moles solute / 0.25 kg solvent = .0599 m = 0.060 m