Classifying Types of Chemical Reactions

Shall We Dance? – Classifying Types of Chemical Reactions Why? Chemical reactions can be classified into different categories. Four common types are synthesis, decomposition, single replacement and double replacement. Specific reactions corresponding to these general types are associated with health issues, environmental problems, and manufacturing processes. In order to use chemical reactions or evaluate their effects, you need to be able to identify the type of reaction. Success Criteria • Identify and differentiate between four types of chemical reactions: synthesis, decomposition, single replacement and double replacement. Prerequisites • • Reaction equation nomenclature Balancing equations New Concepts • • • • Syntheses Decomposition Single replacement Double replacement 1/6 Classifying Types of Chemical Reactions Model 1: Types of Reactions Classification (Type) of Reaction Synthesis Decomposition Single Replacement Double Replacement Example: Using Symbols A + B Æ AB XY Æ X + Y A + BC Æ AC + B Example Reactions H2 (g) + 2O2 (g) Æ 2H2O(l) 2H2O (l) Æ H2 (g) + 2O2 (g) Al(s) + Cu(NO3)2 (aq) Æ Al(NO3)3(aq) + Cu(s) AC + DE Æ AE + DC Pb(NO3)2 (aq) + KI(aq) Æ PbI2(s) + KNO3 (aq) aq = aqueous, g = gas, s = solid, l = liquid Key Questions 1. As shown in the model, what are the unique characteristics of a synthesis reaction? 2. As shown in the model, what are the unique characteristics of a decomposition reaction? 3. As shown in the model, what are the unique characteristics of a single replacement reaction? 4. As shown in the model, what are the unique characteristics of a double replacement reaction? Exercise 1. Identify the type of reaction shown in each of the following chemical equations: KClO3(s) 2KCl(s) + 3O2(g) AgNO3(aq) + KCl(aq) AgCl(s) + KNO3(aq) 2/6 Classifying Types of Chemical Reactions Model 2: Analogy - Dancing with Reactants When you are thinking about the four different types of reactions I'd like you to think about its similarity to dancing (yes, dancing). I'll show you what I mean. The dance… Amy and Bob were both single. No one was talking about "Amy and Bob" being together before the dance. They both go to the dance alone. However, they meet at just the perfect time when a song they both adore is playing. They end up holding hands the entire dance. After that fateful meeting no one ever sees Amy without Bob, they are forever referred to as "Amy and Bob". Analysis of the Dancing Model for Chemical Reactions 1. Represent the drama of Amy and Bob described in Model 2 as a chemical equation? Use A to represent Amy and B to represent Bob. 2. This equation would be classified as a ____________________ reaction. The dance continues… Later that same evening Xavier and Yasmine, who have been ‘the couple’ forever, have a heated quarrel and break up. 3. Represent the drama of Xavier and Yasmine as a chemical equation? Use X to represent Xavier and Y to represent Yasmine. 4. This equation would be classified as a ____________________ reaction. 3/6 Classifying Types of Chemical Reactions The dance continues… In their blissful state, Amy and Bob try to help Xavier and Yasmine reconcile their differences. Amy and Bob agree to stop the quarrel by asking Xavier and Yasmine each to dance. 5. Represent Amy and Bob’s attempt to reconcile Xavier and Yasmine as a chemical equation. 6. This equation would be classified as a ____________________ reaction. 7. What type of reaction is represented in the picture below? Write your own analogy for the reaction illustrated in the picture. 4/6 Classifying Types of Chemical Reactions Exercise 1. Identify the type of reaction in each of the following chemical equations: a. 2 H2(g) + O2(g) 2 H2O(g) b. 2 AgNO3(aq) + Cu(s) c. CaCO3(s) Cu(NO3)2(aq) + 2 Ag(s) CaO(s) + CO2(g) d. NaI(aq) + Cl2(g) 2NaCl(aq) + I2(s) Problems 1. For the reaction between aqueous calcium nitrate and aqueous sodium hydroxide producing the precipitate (solid) calcium hydroxide and aqueous sodium nitrate (a) write a balanced equation for this reaction (b) classify the reaction 2. For the reaction between zinc metal and hydrochloric acid (aqueous) producing zinc chloride (aqueous) and hydrogen gas (a) write a balanced equation for this reaction (b) classify the reaction 5/6 Classifying Types of Chemical Reactions 3. For the reaction between methane gas and molecular oxygen producing carbon dioxide gas and water vapor (a) write a balanced equation for this reaction (b) Can this reaction be classified as a synthesis, decomposition, single replacement or double replacement reaction? Explain your answer. 6/6