Download Chemical Reactions: Synthesis, Decomposition, Displacement, and Combustion and more Slides Chemistry in PDF only on Docsity! TYPES OF CHEMICAL REACTIONS To react or not to react? THAT is the question! Chemical changes are a result of chemical reactions. All chemical reactions involve a change in substances and a change in energy. Neither matter or energy is created or destroyed in a chemical reaction---only changed. Chemical Reactions For example, simple hydrogen gas combined with simple oxygen gas can produce a more complex substance— water! The chemical equation for this synthesis reaction is: 2H2 + O2 2H2O #1 Synthesis Reactions In the cartoon, the skinny bird (reactant) and the worm (reactant) combine to make one product, a fat bird. #1 Synthesis Reactions metal + oxygen metal oxide 4Fe(s) + 3O2(g) 2Fe2O3(s) nonmetal + oxygen nonmetal oxide S(s) + O2(g) SO2(g) metal oxide + water metallic hydroxide MgO(s) + H2O(l) 2Mg(OH)2(s) #1 Synthesis Reactions In a decomposition reaction a more complex substance breaks down into its more simple parts. One reactant yields 2 or more products. Basically, synthesis and decomposition reactions are opposites. reactant -------> product + product AB -------> A + B #2 Decomposition Reactions For example, water can be broken down into hydrogen gas and oxygen gas. The chemical equation for this decomposition reaction looks like: 2H2O 2H2 + O2 #2 Decomposition Reactions Explosions #2 Decomposition Reactions Metallic carbonates, when heated, form metallic oxides and CO2(g). CaCO3(s) CaO(s) + CO2(g). Most metallic hydroxides, when heated, decompose into metal oxides and water. Ca(OH)2(s) CaO(s) + H2O(g). #2 Decomposition Reactions Some oxides, when heated, decompose. 2HgO(s) 2Hg(l) + O2(g) Some acids, when heated, decompose into nonmetallic oxides and water. H2SO4(s) H2O(l) + SO3(g) #2 Decomposition Reactions #3 Single Displacement In a single displacement reaction a single uncombined element replaces another in a compound. – Reactants must be an element and a compound. – Products will be a different element and a different compound. Two reactants yield two products. reactant + reactant ---------> product + product AB + C -------> AC + B – Na + KCl K + NaCl – F2 + LiCl LiF + Cl2 Notice, the guy in the orange shirt steals the date of the other guy. So, a part of one of the reactants trades places and is in a different place among the products. #3 Single Displacement Replacement of a metal in a compound by a more active metal. Fe(s) CuSO4(aq) + FeSO4(aq) + Cu(s) Replacement of hydrogen in water by an active metal. Mg(s) + H2O(aq) MgO4(aq) H2(g) #3 Single Displacement Replacement of hydrogen in acids by active metals. Zn(s) + 2HCl(aq) ZnCl2(aq) + H2(g) Replacement of nonmetal by a more active nonmetal. Cl2(g) + 2NaBr(aq) 2NaCl(aq) + Br2(g) #3 Single Displacement Why do you take a tablet when you have an upset stomach? Calcium carbonate reacts with the hydrochloric acid in your stomach. This is shown in this equation: CaCO3 + 2HCl CaCl2 + H2CO3 #4 Double Displacement Predict the products (assume all of the reactions take place): – CaCl2 + NaOH – CuCl2 + K2S – KOH + Fe(NO3)3 – (NH4)2SO4 + BaF2 #4 Double Displacement #4 Double Displacement
