Types of Chemical Reactions Synthesis & Decomposition Single & Double Displacement April 17th, 2015 Prayer of the Day Blessed are you, loving Father, Ruler of the universe: You have given us Your Son as Your Leader, And have made us temples of Your Holy Spirit. Fill our family with Your light and peace. Have mercy on all who suffer, And bring us to everlasting joy with You. Father, We bless Your Name for ever and ever. Amen. Learning Goals What is a synthesis reaction? What is a decomposition reaction? How do I differentiate between the two? What is a single displacement reaction? What is a double displacement reaction? How do I identify when one is taking place? How do I represent these new types of chemical reactions using chemical formulas? Can I predict how compounds will react? How? Evidence of a Chemical Change A precipitate (insoluble solid) forms Gas formation Change The in odour production of light and heat Types of Chemical Reactions There are 4 main types of Chemical Reactions: 1. Synthesis Reactions 2. Decomposition Reactions 3. Single Displacement Reactions 4. Double Displacement Reactions Synthesis Reaction A synthesis reaction is a chemical reaction in which two or more reactants combine to form a new product Synthesis Reaction * Reactants may be any combination of elements and compounds, but the product will always be a compound * Example from the textbook: The power that is created to allow a space shuttle to blast off is created by a synthesis reaction: Liquid Hydrogen + Liquid Oxygen Water vapour 2H2 (l) + O2 (l) 2H2O (g) REMEMBER HOFBrINCl? It is IMPORTANT to recall that oxygen and hydrogen exist as diatomic molecules. Hydrogen (H2),Oxygen (O2), Fluorine (F2), Bromine (Br2), Iodine (I2) Nitrogen (N2), and Chlorine (Cl2) …. “HOFBrINCl” ALSO remember that these, all exist as gases, EXCEPT for Bromine (liquid) and Iodine (solid) ** you’ll need to know this for when you’re indicating the states of reactants and products in chemical equations! Practice Problems Note: all of the products formed in these reactions are solids 3 Ca(s) + 42 K(s) + 12 Cs(s) + N2(g) O2 (g) Ca3N2 2 K2O P4 (s) 4 Cs3P 2 Al(s) + 3 F2(g) 2 AlF3 Decomposition Reactions A decomposition reaction is a chemical reaction in which a compound breaks down into two or more products Decomposition Reaction ** The products may be any combination of elements and compounds, but the reactant will always be a compound. ** opposite of synthesis! Example from the textbook: Hydrogen gas is produced by the decomposition of water 2H2O (l) 2H2(g) + O2 (g) ** this process is referred to as the electrolysis of water + = + = = + Single Displacement Reactions In a single displacement reaction, a reactive element (a metal or a nonmetal) and a compound react to produce another element and another compound. Therefore, it is a chemical reaction in which an element takes the place of another element in a compound. Single Displacement Reactions If something better (more reactive) comes along, it’ll bump out the other one: Single Displacement Reactions Activity Series An activity series is a list of elements organized according to their chemical reactivity. The most reactive element is at the top, and the least reactive is at the bottom. A more reactive metal will DISPLACE (or REPLACE)a metal in a compound that is below it in the activity series. Activity Series Cu + 2AgNO3 Cu(NO3)2 + 2Ag Because hydrogen ions can be positively charged, metals can take the place of hydrogen in compounds. Hydrogen will be displaced as H2 (Hydrogen gas) Practice on your worksheet! Double Displacement Reactions A double displacement reaction is a chemical reaction in which the positive ions of two compounds change places and form two new compounds. Calcium bromide + Silver nitrate Calcium nitrate + Silver bromide * Metal first! CaBr2 + Ag(NO3) Ca(NO3)2 + AgBr Practice Sheets Do I’ll these for homework check that out tomorrow, so do it, and if you don’t understand something, put a star beside it so you can remember to ask for help!