1. Reactions in Aqueous Solutions
Unit 4:
Reactions in Aqueous Solutions
Day 1: Gummy Bear Death and Precipitation Reactions

2. Warm Up
Balance the following equations for sending a gummy bear to it’s death: ___KClO3 ⟶ ___ KCl + ___KClO4 ____KClO4 ⟶ ____ KCl + ____O2 ____O2+___C6H12O6 ⟶ ___CO2+___H2O 4 1 3 2 1 2 6 1 6 6
4, 1, 3
1, 1, 2
6, 1, 6, 6 ⟶

3. Agenda Gummy Bear Death (Outside) Lecture Notes Practice Problems
Discussion:
What would make this class better?
What would you like to see me do differently to help you be more successful?

4. Pour the two solutions together. Observe what happens
Pour the two solutions together. Observe what happens. Discuss with people at your table why this happens.

5. Lecture Notes Topics: What’s Important?
Definitions:
Electrolyte (strong vs. weak)
Non-electrolyte
Dissociate
Precipitate
Solubility ( and guideline table)
Metathesis Reactions
Types of Equations:
Molecular
Complete ionic
Net ionic
Neutralization
Strong Acids vs. Strong Bases

6. Lecture Notes Topics: What’s Important?
Processes
How to identify strong vs. weak electrolytes
How to predict precipitates
How to predict metathesis reactions
How to write a molecular equation
How to write a net ionic equation
How to write a neutralization reaction

7. What do I need to memorize and what do I need to just practice with?
Memorize Practice
Definitions
Table 4.1, p Solubility Guidelines
Table 4.2, p Activity Series, p. 144
Table 4.3, p Steps for Molecular Eq
Molarity equation Steps for Net Ionic Eq
Dilution equation Steps for Neutralization

8. Solutions
Solutions are defined as homogeneous mixtures of two or more pure substances.
The solvent is present in greatest abundance.
All other substances are solutes.
When water is the solvent, the solution is called an aqueous solution.

9. Aqueous Solutions Substances can dissolve in water by different ways:
Ionic Compounds dissolve by dissociation, where water surrounds the separated ions.
Molecular compounds interact with water, but most do NOT dissociate.
Some molecular substances react with water when they dissolve.

10. Aqueous Solutions

11. Electrolytes and Nonelectrolytes
An electrolyte is a substance that dissociates into ions when dissolved in water.
A nonelectrolyte may dissolve in water, but it does not dissociate into ions when it does so.

12. Electrolytes
A strong electrolyte dissociates completely when dissolved in water.
A weak electrolyte only dissociates partially when dissolved in water.
A nonelectrolyte does NOT dissociate in water.

13. Give it some thought
Which solute will cause the light bulb to glow most brightly if it was dissolved in water, CH3OH, NaOH, or CH3COOH?

14. Solubility of Ionic Compounds
Not all ionic compounds dissolve in water.
A list of solubility rules is used to decide what combination of ions will dissolve.

15. (See Solubility Rules)
Aqueous Solutions
Soluble Compounds
(See Solubility Rules)
Electrolytes
Strong
Weak
Non-Electrolytes
All soluble ionics
Strong Acids
Weak acids
Weak bases
Molecular compounds

16. Precipitation Reactions
When two solutions containing soluble salts are mixed, sometimes an insoluble salt will be produced. A salt “falls” out of solution, like snow out of the sky. This solid is called a precipitate.

17. Predicting Precipitation Reactions
Identify ions present in the reactants
Consider the cation-anion combinations
Use Solubility table to determine if these combinations are soluble or insoluable

18. Which of these are soluble?
(NH4)2S, CaCO3, NaOH, Ag2SO4, Pb(CH3COOH)2

19. Predict the identity of the precipitate…
When MgCl2 and CaS are mixed.
Write the balanced equation.

20. Predict the identity of the precipitate…
When solutions of Fe2(SO4)3 and LiOH are mixed.
Write the balanced equation.

21. Yes or No?
Will a precipitate form when Ba(NO3)2 and KOH are mixed?

22. Discussion What would make this class better?
What would you like to see me do differently to help you be more successful?