Clutch Prep is now a part of Pearson
Ch.12 - SolutionsWorksheetSee all chapters

# Molality

See all sections
Sections
Solutions: Solubility and Intermolecular Forces
Molality
Parts per Million (ppm)
Mole Fraction
Solutions: Mass Percent
Types of Aqueous Solutions
Intro to Henry's Law
Henry's Law Calculations
The Colligative Properties
Boiling Point Elevation
Freezing Point Depression
Osmosis
Osmotic Pressure
Vapor Pressure Lowering (Raoult's Law)
The Freezing Point Depression (IGNORE)

Molality (m) represents the number of moles of solute dissolved per kilogram of solvent.

###### Understanding Molality

Concept #1: Molality

Example #1: A solution contains 24.8 g of sucrose (C12H22O11) dissolved in a 550.0 g of water. Calculate the molality of the solution.

Practice: A solution is prepared by dissolving 43.0 g potassium chlorate, KClO3, in enough water to make 100.0 mL of solution. If the density of the solution is 1.760 g/mL, what is the molality of KClO3 in the solution?

Practice: The density of a 15.7 M methanol (CH3OH) solution is 0.858 g/mL. If H2O is the solvent, what is the molality of the solution?

###### Osmolality

Concept #2: Osmolality

Osmolality or Ionic Molality, represents number of dissolved particles in a solution.

Example #2: What is the osmolality of total ions in an aqueous solution prepared by dissolving 0.400 moles of Pb(NO3)in 750.0 g water?

Practice: What is the ionic molality of sodium ions in a solution of 25.7 g NaNO3 dissolved in enough water to make a 150.0 mL of solution? Density of the solution is 1.02 g/mL.