Types of Chemical Reactions

1. 11.2 Types of Chemical Reactions • The heat and smoke of burning charcoal are the products of a combustion reaction. Combustion is one of the five general types of chemical reactions. If you can recognize a reaction as being a particular type, you may be able to predict the products of the reaction.

2. Five general types of chemical reactions: combination (synthesis) decomposition single-replacement double-replacement combustion See websites for videos and animations http://www.youtube.com/watch?v=i-HHvx1VC_8&NR=1 http://www.youtube.com/watch?v=tE4668aarck&feature=related Classifying Reactions 11.2

3. 11.2 Classifying Reactions • Combination Reactions • A combination reaction is a chemical change in which two or more substances react to form a single new substance.

5. for Conceptual Problem 11.4

6. 11.2 Classifying Reactions • Decomposition Reactions • A decomposition reaction is a chemical change in which a single compound breaks down into two or more simpler products.

10. for Conceptual Problem 11.5

11. 11.2 Classifying Reactions • Single-Replacement Reactions • A single-replacement reaction is a chemical change in which one element replaces a second element in a compound.

12. 11.2 Classifying Reactions • The activity series of metals lists metals in order of decreasing reactivity. • For a single-replacement reaction to occur, the element that is displaced must be less active than the element that is doing the displacing. • Metals above Hydrogen in the activity series will replace H from acids. • Zn(s) + 2 HCl (aq) → H2 (g) + ZnCl2 (aq) • Metals below Hydrogen in the activity series will not react with acids.

16. for Conceptual Problem 11.6

17. 11.2 Classifying Reactions • Double-Replacement Reactions • A double-replacement reaction is a chemical change involving an exchange of positive ions between two compounds.

21. 11.2 Classifying Reactions • Combustion Reactions (see regents ref tables) • A combustion reaction is a chemical change in which an element or a compound reacts with oxygen, often producing energy in the form of heat and light.

24. Note • your regents reference tables are helpful for writing equations for combustion reactions • Examples:

25. 11.2 Predicting the Products of a Chemical Reaction • Predicting the Products of a Chemical Reaction • How can you predict the products of the five general types of reactions? • The number of elements and/or compounds reacting is a good indicator of possible reaction type and thus possible products.

26. 11.2 Predicting the Products of a Chemical Reaction

27. 11.2 Predicting the Products of a Chemical Reaction

28. 11.2 Predicting the Products of a Chemical Reaction

29. 11.2 Predicting the Products of a Chemical Reaction

30. 11.2 Predicting the Products of a Chemical Reaction

31. 11.2 Section Quiz. • 11.2.

32. 11.2 Section Quiz. • 1. What type of reaction is described by the following equation? • 6Li + N2 2Li3N • combination reaction • decomposition reaction • single-replacement reaction • combustion reaction

33. 11.2 Section Quiz. • 2. Balance the following equation and indicate whether it represents a combustion, combination, or decomposition reaction. • H2SO4 H2O2 + SO2 • H2SO4 H2O2 + SO2, combination reaction • H2SO4 H2O2 + SO2, decomposition reaction • H2SO4 2H2O2 + SO2, combination reaction • H2SO4 2H2O2 + SO2, decomposition reaction

34. 11.3 Reactions in Aqueous Solution • Structures in limestone caverns are formed when carbon dioxide converts calcium hydrogen carbonate into calcium carbonate. The calcium carbonate precipitates and forms dramatic stalactites and stalagmites. You will learn to predict the formation of precipitates and write equations to describe the reactions that produce them.

35. 11.3 When AgNO3 (aq) and NaCl (aq) are mixed, a white precipitate of AgCl (s) is formed. We can write a balanced equation to describe this double-replacement reaction: AgNO3 (aq) + NaCl (aq) → AgCl (s) + NaNO3 (aq) Two other types of equations can be written for this reaction (complete ionic equation and a net-ionic equation) • A complete ionic equation is an equation that shows dissolved ionic compounds as dissociated free ions.

36. 11.3 Net Ionic Equations An ion that appears on both sides of an equation and is not directly involved in the reaction is called a spectator ion. The net ionic equation is an equation for a reaction in solution that shows only those particles that are directly involved in the chemical change.

37. 11.3 Net Ionic Equations Complete ionic equation: Sodium ions and nitrate ions are not changed during the chemical reaction of silver nitrate and sodium chloride so the net ionic equation is

38. 11.3 Predicting the Formation of a Precipitate • Predicting the Formation of a Precipitate • How can you predict the formation of a precipitate in a double-replacement reaction? • You can predict the formation of a precipitate by using the general rules for solubility of ionic compounds and by using the regents reference tables.

39. 11.3 Predicting the Formation of a Precipitate Will a precipitate form when a sodium carbonate solution is mixed with a barium nitrate solution? Hints: what are the products? and are those products soluble? (Use your reference tables).

40. Predicting the Formation of a Precipitate 11.3 Balanced equation: Ba(NO3)2 + Na2CO3 (aq)→ BaCO3 (s) + 2 NaNO3 (aq) Complete ionic equation: Ba2+(aq) + 2 NO3 - (aq) + 2 Na+(aq) + CO3 2- (aq) → BaCO3(s) + 2 Na+(aq)+ 2 NO3 - (aq) Net Ionic equation: Sodium nitrate is soluble but barium carbonate is insoluble. The net ionic equation is

41. 11.3 Section Quiz. • 2. Which one of the following products of double-replacement reactions would NOT form a precipitate? • AgCl • PbSO4 • Mg(OH)2 • Mo(NO3)2

42. 11.3 Section Quiz • 3. Which reaction will NOT produce a precipitate from aqueous solution? • Hg2(NO3)2 + KCl • FeSO4 + Ba(OH)2 • Pb(NO3)2 + Na2CO3 • NaBr + Al2(SO4)2