Honors Chemistry
Study Guide – Chapter 13: Solutions
Test Date: ______________________________________
Chapter Four:

Making solutions, Molarity, & Dilutions
o Molarity Calculations
 Determine moles, mass, volume, or molarity depending on the info given in the
problem (remember that M = # moles solute / 1 L solution)
o Dilution – when you take a more concentrated solution (like a stock solution) and make
a less concentrated solution
 M1V1 = M2V2
o Making Solutions (from solids and dilutions)
 Solids: Need to know what volume & concentration you are making  this way
you can calculate moles, and thus mass, of the solid you will need.
 Dilutions: Use the dilution equation to determine what volume of concentrated
you will need to dilute down and add then water to desired volume
 Always use a volumetric flask for solutions  flask can measure 1 volume only
Chapter Thirteen:

The Solution Process
o Terms to know: solution, solute, solvent (the solute dissolves into the solvent)
o Energy Changes of solution process
 three steps separation of solute particles, separation of solvent particles,
formation of solute-solvent interactions (is each step endo or exothermic?)
 When is an overall solution endothermic? exothermic?
o When a solute is being dissolved in a solvent…
 Dissolution vs. Crystallization – two opposite processes that occur in a solution in
dynamic equilibrium (when the rate of dissolution equals the rate of crystallization
no more solute can be dissolved in the solution)
o Solubility Curves & Saturated/Unsaturated/Supersaturated solutions
 The line represents a SATURATED solution dissolved (typically) in 100 g of water
(above line= supersaturated; below line = unsaturated)

Factors that Affect Solubility of a Solute
o Nature of the solute and solvent (“Like dissolves Like”)
 polar solvents dissolves polar (and ionic) solutes
 nonpolar solvents dissolve nonpolar solutes
 be able to determine what solvent a substance will be more likely do dissolve in
based on polarity (like in the review sheet)
 Terms to know: miscible vs. immiscible
o Solubility for gases:
 What increases solubility of a gas?  larger molar mass, increased pressure,
decreased (colder) temperatures
o Solubility for solids:
 What increases solubility of a solid?  stirring/agitation, increased (warmer)
temperatures, decreased surface area (smaller particle size), pressure has NO
affect on solids

Concentration Terms and Calculation
 Memorize the meaning of percent by mass, mole fraction, molarity, and molality
 parts per million and parts per billion are specific types of % by mass calculation
(ppm multiply by 106 and ppb multiply by 109 instead of 100 like in reg. % by mass)
 Calculations: many varied calculations including conversions
between the concentration units (use the solutions table to help)

Colligative Properties – physical properties of solutions based on # of solute particles
o Recall that colligative properties depend on the # of solute particles = i = van’t hoff factor…
Before solving any calculations, determine if the solute is an electrolyte (ionic or strong
acid/base) or nonelectrolyte (molecular compounds)
 if the solute is an electrolyte, the concentration of solute particles will be multiplied
by the number of ions present in solution before the equations of colligative
properties are solved.
o Vapor Pressure Lowering
 Calculation: Raoult’s Law  Psoln = (Xsolvent)(P solvent) [Psoln = partial
pressure above the solution, Xsolvent = mole fraction of SOLVENT, P solvent =
partial pressure above pure, original solvent (before any solute was added)]
 The addition of solute particles LOWERS the vapor pressure exerted above a
solution
o Boling Point Elevation
 Calculation: Tb = i  Kb  m
[Tb = change in boiling temperature, i = #
solute particles, Kb = constant based on SOLVENT, m = molality] … to find
new BP of solution, ADD Tb to the original BP of the solvent
 The addition of solute particles RAISES the boiling point of a solution (when
compared to the boiling point of pure solvent)
o Freezing Point Depression
 Calculation: Tf = i  Kf  m
[Tf = change in boiling temperature, i = #
solute particles, Kf = constant based on SOLVENT, m = molality] … to find
new FP of solution, SUBTRACT Tf from the original FP of the solvent
 The addition of solute particles LOWERS the freezing point of a solution (when
compared to the boiling point of pure solvent)
o Osmotic Pressure
 When two different concentrations of solutions are separated by a semipermeable
membrane, the direction of solvent always flows from less concentrated solute side
to more concentrated solute side (goal is to achieve equilibrium of concentrations)
 When one side of the semipermeable membrane is a pure solvent and the other
side is a solution, osmotic pressure is the pressure required to stop osmosis (stop
the flow of solvent from pure side to solution side)
 Calculation:  = iMRT [ = osmotic pressure in atms, i = # solute particles,
M = molarity, R = ideal gas constant 0.0821 Latm/molK, T = temperature in
Kelvin]
o Determination of Molar Mass from Colligative Properties
 Calculations: use the information given and the colligative properties
formulas to solve for molar mass (g/mol) of an unknown substance… if you
can find the mass and the # of moles you can divide mass by moles to get
g/mol