Solution Equilibrium

1
Solution Equilibrium

• Chap. 15-17

2
Review

• Where weve been

3
Terms Review

• Atomic Theory
• Naming Compounds
• Using the Periodic Table
• Protons
• Neutrons
• Orbitals

• Electrons
• Balance Charges
• Balance Chemical Equations
• Converting Units
• Stoichiometry
• Limiting Reagent

4
Terms Review

• Kinetic-Molecular Theory
• Intermolecular Forces
• Phase Diagrams
• Enthalpy (Heat) of a Rxn

• Calorimetry
• Heat Capacity
• Specific Heat
• Pressure Units
• Temperature Units
• Ideal Gas Law

5
Concept Review

• Converting Units
• mass ? mass
• weight ? weight
• pressure ? pressure
• mass ? volume
• mass ? moles
• mass ? particles

6
Converting Units
7
Lab Calculations

• Common calculations in lab
• Mass of a substance
• Volume of a substance
• Amount of a substance (in moles)
• Percent yield
• Percent error
• Limiting reagent

8
Lab Review
9
New Terms

• Equilibrium
• Precipitation
• Solubility
• Net-ionic equation
• Common-ion effect
• Le Chateliers principle

• Solute
• Solvent
• Soluble
• Insoluble
• Solution
• Effect of impurities on solvents
• Haber Process

10
New Terms

• Factors affecting solubility rate
• Rate of solubility
• Equilibrium Constant

• Molarity
• Molality
• Saturation
• Solubility Curve
• Reaction Quotient

11
Equilibrium

• Reaction going forward is the same as the
  reaction going backwards.
• Forward rxn A?B kf A
• Reverse rxn B?A kr B
• kf A kr B

12
Solutions

• SoluteWhat gets dissolved
• SolventWhat does the dissolving
• SolubleDissolves in solvent
• InsolubleDoesnt dissolve in solvent

13
Solutions

• Sudan IV, is insoluble in H2O, but soluble in
  alcohol.

14
Solutions
15
Precipitation

• What falls out of a solution
• Heterogeneous mixtures vs. homogeneous mixtures
• Colloidsparticles to big to be in solution, yet
  small enough to be in suspension. Particles do
  not settle!
• Solubility rules

16
Precipitation

• Ca(C2H3O2)2 ? Ca2 2(C2H3O2)1-
• Na(OH) ? Na1 (OH)1-
• Using the solubility rules, what will happen if I
  mix the two solutions?

17
Le Chateliers Principle

• Altering the environment changes a rxns
  equilibrium.

18
Le Chateliers Principle

• What is the rxn in the beaker?
• Ca2 2(OH)1- ? Ca(OH)2 (s)
• Under what conditions could I dissolve the
  Ca(OH)2?
• Not every rxn is reversible.
• Not every reversible rxn is easily reversed.

19
Effects of Impurities

• Tendency to lower boiling pt.
• Tendency to lower freezing pt.
• Tendency to melt over a large range of temps.
• Example
• Pure substance A melts at 80C
• Impure substance A melts from 60-90C

20
Solution Properties
21
Complete-ionic equations

• Pb(NO3)2 2KI ? PbI2 2K(NO3)
• Pb(NO3)2(aq) 2KI(aq) ? PbI2(s) 2K(NO3) (aq)
• Pb2(aq) 2(NO3)1-(aq) 2K(aq) I-(aq) ?
  PbI2(s) 2K(aq) 2(NO3)1-(aq)

22
Net-ionic equations

• Pb2(aq) 2(NO3)1-(aq) 2K(aq) I-(aq) ?
  PbI2(s) 2K(aq) 2(NO3)1-(aq)
• Pb2(aq) I-(aq) ? PbI2(s)
• Spectator ionsions occurring on both sides of
  the equation have no role in the net reaction.
  They do nothing.

23
Net-ionic equations

• Writing net-ionic equations is as easy as 1, 2,
  3.
• 1. Write a balanced chemical equation.
• 2. Rewrite the equations showing ions.
• 3. Cancel ions showing on both sides of the
  reactions.

24
Common-Ion Effect

• Dissociation of a weak electrolyte is decreased
  when a strong electrolyte enters the solution.
• Electrolytesubstance that produces ions in a
  solution, which conduct an electric current.

25
Haber Process

• Technique developed to produce ammonia from its
  elements
• Jewish descendent Fritz Haber developed the
  process for his country of Germany.
• Nazis proceeded to kick him out several years
  later

26
Solubility Rate

• Amount per unit time that the solute gets
  dissolved
• Conditions affecting rate
• Temperature
• Surface area/Particle size
• Increase pressure/Decrease volume
• pH

27
Equilibrium Constant

• The equilibrium constant, k, is a ratio of the
  products to the reactants
• aA bB ? cC dD
• keq CcDd / AaBb

28
Molarity/Molality

• Molarityconcentration of a substance
• M moles / Liter
• Molalityconcentration of a substance
• m moles / kg of solvent
• Rarely used

29
Molarity
30
Molality
31
Saturation/Dilution

• Saturation is the point at which no more solute
  will dissolve into the solvent.
• Dilution is a method of lowering the
  concentration of solute by adding more water.

32
Saturation/Dilution
33
Solubility Curve

• p. 516, 517
• Solubility vs. Temperature for solids

34
Solubility Curve

• p. 516, 517
• Solubility vs. Temperature for gases

35
Reaction Quotient

• Qcomparison of reactants / products to the
  keq
• Helps determine if a reaction favors the products
  or the reactants at the given concentration

36
Reaction Quotient

• 2H2O2 ? O2 2H2O
• While water is ok, and O2 is good for breathing,
  O2 is very flammable.

37
Quick Question

• What are some places we would not want high
  concentrations of O2?
• Medicine cabinets, closets, space shuttles,
  airplanes, cars, etc.

38
Quick Question

• Why is the H2O2 you buy from the store ok to put
  in your cabinet?
• The concentration is only 5.

39
Reaction Quotient

• 2H2O2 ? O2 2H2O
• While water is ok, and O2 is good for breathing,
  O2 is very flammable.
• If I need to store H2O2, then I need to know if
  the reaction favors reacants (H2O2) or prodcuts
  (O2 H2O).