1. Prentice Hall © 2003Chapter 4 Chapter 4 Aqueous Reactions and Solution Stoichiometry

2. Prentice Hall © 2003Chapter 4 Electrolytic Properties Aqueous solutions have the potential to conduct electricity (ions needed) There are three types of solutions: Strong electrolytes Weak electrolytes Nonelectrolytes 4.1 General Properties of Aqueous Solutions

3. Prentice Hall © 2003Chapter 4 Ionic Compounds in Water Ions dissociate (break apart) in water In solution, each ion is surrounded by water molecules Transport of ions through solution causes flow of current

4. Prentice Hall © 2003Chapter 4 Molecular Compounds in Water Molecular compounds in water: no ions are formed If there are no ions in solution, there is nothing to transport electric charge

5. Prentice Hall © 2003Chapter 4 Electrolytic Properties

6. Prentice Hall © 2003Chapter 4 Strong and Weak Electrolytes Strong electrolytes: completely dissociate in solution Acids ionize Soluble Salts Strong Acids (HCl, HBr, HI, HNO 3, HClO 4, HClO 3, H 2 SO 4 ) HCl (aq)  H + (aq) + Cl - (aq) KNOW THE 7 STRONG ACIDS!

7. Prentice Hall © 2003Chapter 4 Weak electrolytes: produce a small concentration of ions when they dissolve (weak acids) – These ions exist in equilibrium with the un-ionized substance – For example:

8. Prentice Hall © 2003Chapter 4 Sample Problems # 5 & 9

9. Prentice Hall © 2003Chapter 4 When two aqueous solutions are mixed and a solid is formed, the solid is called a precipitate 4.2 Precipitation Reactions

10. Text, P. 118 You must know your Solubility Rules: there will be a quiz!

11. Prentice Hall © 2003Chapter 4 Sample Problem # 11

12. Prentice Hall © 2003Chapter 4 Exchange (Metathesis) Reactions Metathesis reactions involve swapping ions in solution: (anions/cations switch partners) AX + BY  AY + BX Metathesis reactions will lead to a change in solution if one of three things occurs: –an insoluble solid is formed (precipitate) –weak or nonelectrolytes are formed –an insoluble gas is formed Signs of a chemical reaction!

13. Prentice Hall © 2003Chapter 4 These are not to be confused with replacement reactions: Zn (s) +2HCl (aq)  ZnCl 2(aq) + H 2(g) These have the general form A + BX  AX + B and are usually Redox (more on this at a later time)

14. Prentice Hall © 2003Chapter 4 Sample Problems # 13, 17, 19