1. Unit 6 – Aqueous Reactions and Solution Stoichiometry

2. Solutions and Electrolytes
Solution is a homogeneous mixture of two or more substances
Solvent
Solute
Electrolyte form ions in aqueous solution
Ionic compounds
H2O
Non electrolyte do not form ions in solution
Molecular compounds

3. Strong vs Weak Electrolytes
Electrolyte strength determined amount of ions present in aqueous solutions
Strong Electrolytes – dissolved compound that exists mainly or completely as ions
Acids, Ionic Compounds
HCl → H+ + Cl-
Weak Electrolytes – dissolved compound that exists mainly as molecules not ions
HC2H3O2 ↔ H+ + C2H3O2-

4. Precipitation Reactions
Precipitation reactions result in formation of insoluble solid
Solubility is the amount of a substance that can be dissolved in a large amount of solvent
Compound with solubility less than 0.01mol/L is insoluble
Can not determine solubility based on physical properties

5. Solubility Rules

6. Predicting Solubility
Determine whether the following compounds are soluble or insoluble and why.
Sodium carbonate
Lead sulfate
Barium nitrate
Cobalt (II) hydroxide
Ammonium phosphate

7. Predicting Precipitation Reactions
To predict whether or not a precipitate forms look at all possible combinations of present ions and see if any form an insoluble solid.
Write the balance reactions for the following reactions.
Barium chloride and Potassium sulfate
Iron (III) sulfate and Lithium hydroxide
Barium nitrate and potassium hydroxide

8. Ionic Equations Molecular equations Complete Ionic equations
Pb(NO3)2(aq) + 2KI(aq) → PbI2(s) + 2KNO3 (aq)
Complete Ionic equations
Pb2+ + 2NO3- + 2K+ + 2I- → PbI2 + 2K+ + 2NO3-
Spectator ions
Nitrate, potassium
Net Ionic equation
Pb2+ + 2I- → PbI2

9. Writing Net Ionic Equations
Write balanced reactions
Rewrite equation to show ions in solution
Identify and cancel spectator ions
If all ions are spectator ions no reaction occurs

10. Net Ionic Equation Practice
Write the net ionic equations for the reactions between:
Calcium chloride and sodium carbonate
Silver nitrate and potassium phosphate

11. Acid and Base Reactions
Acids are substances that ionize in aqueous solution to form H+ ions
Monoprotic
HNO3 → H+ + NO3-
Diprotic
H2SO4 → 2H+ + SO42-
Bases are substances that accept H+ ions
Produce OH- ions when dissolved in water

12. Strong and Weak Acid and Bases
Strong acids, bases = Strong electrolytes
Weak acids, bases = Weak electrolytes

13. Electrolytes Summary

14. Classifying Electrolytes
Classify the following substances as strong, weak or nonelectrolytes.
Calcium chloride
Nitric Acid
Ethanol (C2H5OH)
Formic Acid (HCHO2)
Potassium hydroxide
Rank solutions of calcium nitrate, table sugar, sodium acetate, and acetic acid in order of increasing conductivity.

15. Neutralization Reactions
Acids and base can change the color of dyes
Litmus
Mix acids and bases and neutralization reaction occurs
HCl + NaOH → H2O + NaCl
H+ + OH- → H2O
Write the net ionic equation for reactions between
Hydrochloric acid and magnesium hydroxide
Acetic acid and barium hydroxide

16. Acid base Reactions Reactions that form gases
Bases other than OH- may react with acids to form molecules
2HCl + Na2S → H2S + 2NaCl
2H+ + S2- → H2S
Carbonates and bicarbonates react with acids to form CO2
HCl + NaHCO3 → NaCl + H2CO3
H2CO3 → H2O + CO2
HCl + NaHCO3 → NaCl + H2O + CO2
H+ + HCO3- → H2O + CO2

17. Homework
3, 5, 10, 11, 14, 15, 18, 23, 26, 30, 31