Types of Reaction and Predicting Reactions Concept Presentation Winnie Ho HS Science Instructors Janine Extavour & Marty Zatzman

Goal of this presentation Grade 10 teachers: - Differences between Gr 10 and 11 and how to prepare our students Grade 11 teachers: What Gr 10 students know and common roadblocks in this topic

Teaching sequence in 11U Unit 1- Matter, Chemical trends, and Chemical Bonding Unit 2 - Chemical reaction Prior knowledge: - Ionic compounds and covalent molecules - Nomenclature - Balancing equation - Classifying reactions Important prior knowledge

Curriculum expectation Grade 10 – Chemistry expectations on types of reaction C2.3 investigate simple chemical reactions, including synthesis, decomposition, and displacement reactions, and represent them using a variety of formats (e.g., molecular models, word equations, balanced chemical equations) C3.5 describe, on the basis of observation, the reactants in and products of a variety of chemical reactions, including synthesis, decomposition, and displacement reactions (e.g., reactions occurring when magnesium burns or in the production of oxygen from hydrogen peroxide; the reaction of iron and copper sulphate; reactions occurring when fossil fuels burn) Grade 11 – Chemical reaction (selected expectations on types of reaction) C2.4 predict the products of different types of synthesis and decomposition reactions (e.g., synthesis reactions in which simple compounds are formed; synthesis reactions of metallic or non-metallic oxides with water; decomposition reactions, in which a chemical compound is separated into several compounds) C2.5 predict the products of simple displacement reactions, using the metal activity series and the halogen series. C2.6 predict the products of double displacement reactions (e.g. formation of precipitates or gases; neutralization) C2.7 design an inquiry to demonstrate the difference between a complete and an incomplete combustion reaction C2. 10 plan and conduct an inquiry to demonstrate a simple displacement reaction, using elements from the metal activity series C3.1 identify various types of chemical reactions, including synthesis, decomposition, single displacement, double displacement, and combustion

Comparison Grade 10 - Classifying all four reaction types + Neutralization Grade 11 All four reaction types + Activity series + Solubility rules + Neutralization + Combustion + Nuclear reactions Focus on lab inquiry Prediction of products

Diagnostic assessment nitric acid + potassium hydroxide  ____________+ water Type: ___________ zinc + ___________  zinc nitrate solution + copper Type: ___________ __________ acid + zinc carbonate  zinc sulfate + water + carbon dioxide Type: ___________ calcium + chlorine  _____________________ Type: ___________ magnesium + hydrochloric acid  __________ + hydrogen Type: ___________ propane + oxygen  _____________________ + water Type: ___________

General Chemical Equation Synthesis Reaction Type General Chemical Equation Synthesis A + B  AB Decomposition AB  A + B Single Displacement M + BC  MC + B N + BC  BN + C Double Displacement AB + CD  AD + CB Combustion CxHy + _O2 _ CO2 +_ H2O +  Sodium and Chlorine reacts to form Sodium chloride +   + +  + 

Roadblock #1 Failure to connect symbols to the actual elements A + B  AB A can represent an element, a diatomic molecule, or a compound. The ordering of the symbols is important.

Can you find the mistakes?

Macroscopic Microscopic Symbolic Most of our teaching strategy consist of macroscopic and symbolic. A disconnect occurs. According to research on chemistry education, chemistry should be taught both at all three levels. Symbolic

Roadblock #2 Predicting synthesis vs. combustion rxn Grade 10 – synthesis reaction Grade 11 –combustion reaction Reaction of a substance with oxygen, producing oxides and energy (Nelson text) Combustion of magnesium as an example of a synthesis reaction Exothermic reaction Anyone classify this one as combustion in grade 10? What made you decide to do so?

Synthesis Reaction! Brad + Angelina  Brangelina

Tom + Katie  TomKat

Roadblock #3 Zn(s) + CuSO4(aq)--> Predicting single displacement reactions Zinc is more reactive than copper and will displace coppers ions out of solution. Zn(s) + CuSO4(aq)--> ZnSO4(aq) + Cu(s)

Video Safety concerns: Demo: Li, Na, K with water Goggles, small quantity

Alternatives M + BC  MC + B M= metal element N + BC  BN + C N= non-metal element

Roadblock #4 Predicting double displacement reactions Hg22+ is a diatomic cation Hg2+ - Hg2+ If a reaction does not produce a precipitate, a gas, or water, then it is not a DD reaction.

Solubility table KOH(aq) + NH4Cl (aq)--> No Reaction

KOH(aq) + NH4Cl (aq)--> no reaction

Use of states symbols are important More consistent usage of state symbols in grade 10 when writing out chemical equations. e.g., NaOH(aq) + HCl(aq)  H2O (l) + NaCl (aq) Textbook now are better

Societal implications Synthesis reaction Rusting, Galvanization, Alloy Decomposition reaction Production of sodium using electrolysis of molten sodium chloride Single displacement reaction Extracting metals, smelting process, Bromine compound as fire retardant Double displacement reaction Geochemistry (solubility rules allows students to understand why some elements exist as compounds in nature), corrosion of statues Combustion Greenhouse effect Talk about many processesSynthesis reactionRusting, Galvanization, AlloyDecomposition reactionProduction of sodium using electrolysis of molten sodium chlorideSingle displacement reactionExtracting metals, smelting process, Bromine compound as fire retardantDouble displacement reactionGeochemistry (solubility rules allows students to understand why some elements exist as compounds in nature), corrosion of statuesCombustionGreenhouse effect

Differentiated instruction Computer resources Gizmos Metals in aqueous solutions simulation Differentiated instruction Computer simulation (modified versions of activities) Video Group work on making connections issues

Thank you.