1. 1 Net ionic equations

2. 2 REDOX REACTIONS EXCHANGEAcid-BaseReactionsEXCHANGEGas-FormingReactions EXCHANGE: Precipitation Reactions REACTIONS

3. 3 TerminologyTerminology In solution we need to define the - SOLVENTSOLVENT the component whose physical state is preserved when solution forms SOLUTESOLUTE the other solution component

4. 4 IONIC COMPOUNDS Compounds in Aqueous Solution Many reactions involve ionic compounds, especially reactions in water — aqueous solutions. KMnO 4 in water K + (aq) + MnO 4 - (aq)

5. 5 An Ionic Compound, CuCl 2, in Water CCR, page 149

6. 6 How do we know ions are present in aqueous solutions? The solutions conduct electricity! They are called ELECTROLYTES HCl, MgCl 2, and NaCl are strong electrolytes. They dissociate completely (or nearly so) into ions. Aqueous Solutions

7. 7 HCl, MgCl 2, and NaCl are strong electrolytes. They dissociate completely (or nearly so) into ions. Aqueous Solutions

8. 8 An acid -------> H + in water ACIDSACIDS Some strong acids are HClhydrochloric H 2 SO 4 sulfuric HClO 4 perchloric HNO 3 nitric HNO 3

9. Basic Chemistry Copyright © 2011 Pearson Education, Inc. 9 Strong acids make up six of all the acids have weak conjugate bases Strong Acids

10. Basic Chemistry Copyright © 2011 Pearson Education, Inc. 10 Strong Bases Strong bases are formed from metals of Groups 1A (1) and 2A (2) include LiOH, NaOH, KOH, and Ba(OH) 2 dissociate 100% in water KOH(s) K + (aq) + OH − (aq) Bases in household products are used to remove grease and to open drains.

11. 11 Aqueous Solutions Acetic acid ionizes only to a small extent, so it is a weak electrolyte. CH 3 CO 2 H(aq) ---> CH 3 CO 2 - (aq) + H + (aq)

12. 12 Weak Acids WEAK ACIDS = weak electrolytes CH 3 CO 2 H acetic acid H 2 CO 3 carbonic acid H 3 PO 4 phosphoric acid HF hydrofluoric acid Acetic acid

13. Basic Chemistry Copyright © 2011 Pearson Education, Inc. 13 Weak acids make up most of the acids have strong conjugate bases Weak Acids

14. Basic Chemistry Copyright © 2011 Pearson Education, Inc. 14 Weak Bases Weak bases are poor acceptors of protons dissociate only slightly in water produce only a few ions in water are used in household products such as cleaners NH 3 (g) + H 2 O(l) NH 4 + (aq) + OH − (aq)

15. 15 Aqueous Solutions Acetic acid ionizes only to a small extent, so it is a weak electrolyte. CH 3 CO 2 H(aq) ---> CH 3 CO 2 - (aq) + H + (aq)

16. 16 Aqueous Solutions Some compounds dissolve in water but do not conduct electricity. They are called nonelectrolytes. Examples include: sugarethanol ethylene glycol Examples include: sugarethanol ethylene glycol

17. Basic Chemistry Copyright © 2011 Pearson Education, Inc. 17 Learning Check Identify each of the following as a strong or weak acid or base: A. HBr B. HNO 2 C. NaOH D. H 2 SO 4 E. Cu(OH) 2 strong acid weak acid strong base strong acid weak base

18. Basic Chemistry Copyright © 2011 Pearson Education, Inc. 18 Learning Check A. Identify the stronger acid in each pair. 1. HNO 2 or H 2 S 2. HCO 3 - or HBr 3. H 3 PO 4 or H 3 O + B. Identify the stronger base in each pair. 1. NO 3 - or F - 2. CO 3 2- or NO 2 - 3. OH - or H 2 O

19. Basic Chemistry Copyright © 2011 Pearson Education, Inc. Acid-Base Reactions The “driving force” = formation of water. NaOH ( aq ) + HCl ( aq ) ’ NaCl ( aq ) + H 2 O (l) Net ionic equation OH - ( aq ) + H + ( aq ) ’ H 2 O (l) OH - ( aq ) + H + ( aq ) ’ H 2 O (l) This applies to ALL reactions of STRONG acids and bases.

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21. Basic Chemistry Copyright © 2011 Pearson Education, Inc.

22. Gas-Forming Reactions The chemistry of metal carbonates. CO 2 and water ’ H 2 CO 3 H 2 CO 3 (aq) + Ca 2+ ’ H 2 CO 3 (aq) + Ca 2+ ’ 2 H + (aq) + CaCO 3 (s) (limestone) 2 H + (aq) + CaCO 3 (s) (limestone) Adding acid reverses this reaction. MCO 3 + acid ’ CO 2 + salt

23. Basic Chemistry Copyright © 2011 Pearson Education, Inc.

26. 26 Water Solubility of Ionic Compounds Common minerals are often formed with anions that lead to insolubility: sulfidefluoride sulfidefluoride carbonateoxide carbonateoxide Azurite, a copper carbonate Iron pyrite, a sulfide Orpiment, arsenic sulfide

27. 27 Precipitation Reactions The “driving force” is the formation of an insoluble compound — a precipitate. Pb(NO 3 ) 2 (aq) + 2 KI (aq) ’ 2 KNO 3 (aq) + PbI 2 (s) Net ionic equation Pb 2+ (aq) + 2 I - (aq) ’ PbI 2 (s)

28. 28 Net Ionic Equations Mg(s) + 2 HCl(aq) --> H 2 (g) + MgCl 2 (aq) We really should write Mg(s) + 2 H + (aq) + 2 Cl - (aq) ---> H 2 (g) + Mg 2+ (aq) + 2 Cl - (aq) The two Cl - ions are SPECTATOR IONS — they do not participate.

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30. 30 Li + (aq) + Na + (aq) + OH - (aq) + CrO 4 - (aq) ---> Li + (aq) + Na + (aq) + OH - (aq) + CrO 4 - (aq) Cr 3+ (aq) + Na + (aq) + NO 3 - (aq) + Br - (aq) ---> Cr 3+ (aq) + Na + (aq) + NO 3 - (aq) + Br - (aq)

31. 31 If one ion from the “Soluble Compd.” list is present in a compound, the compound is water soluble. Water Solubility of Ionic Compounds Screen 5.4 & Figure 5.1

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