Types of Reactions

Types of Reactions Synthesis Decomposition Single-Replacement Double-Replacement

Synthesis Synthesis – 2 or more substances combine to form a single compound. a) A + B----> AB b) ex. Mg + O2 ----> MgO2 or 2H2 + O2 ----> 2H2O c) 2 elements will produce a binary compound.

Synthesis Two or more elements or simple compounds combine to form (synthesize) one product A + B AB 2Mg + O2 2MgO 2Na + Cl2 2NaCl SO3 + H2O H2SO4

Decomposition Decomposition – Single compound breaks down to form 2 or more single substances. a) AB ----> A + B b) ex. 2HgO ----> 2Hg + O2 or MgCl2 ----> Mg + Cl2 c) Binary compounds will break down into their . d) Most require , __ or ______ Elements Heat Light Electricity

Decomposition One substance is broken down (split) into two or more simpler substances. AB A + B 2HgO 2Hg + O2 2KClO3 2KCl + 3O2

Learning Check R1 Classify the following reactions as 1) synthesis or 2) decomposition: ___A. H2 + Br2 2HBr ___B. Al2(CO3)3 Al2O3 + 3CO2 ___C. 4 Al + 3C Al4C3 1 2 1

Single Replacement Single replacement – An element takes the place of another element that is part of a compound. a) Product has new ______ and different b) A + BC ----> AC + B or D + BC ----> BD + C c) ex. Zn + 2HCl ----> ZnCl2 + H2 d) More reactive replaces less reactive one and opposite doesn’t occur e) ZnCl2 + H2 ----> No reaction Element Compound Element

Single Replacement Zn + 2HCl ZnCl2 + H2 Fe + CuSO4 FeSO4 + Cu A more reactive element takes the place of a less reactive element in a compound. A + BC AB + C Zn + 2HCl ZnCl2 + H2 Fe + CuSO4 FeSO4 + Cu

Double Replacement Double Replacement – Ions in 2 compounds switch places. a) 1 of the products is usually a ___, or _____ b) AB + CD ----> AD + CB c) NaCl + AgF ----> NaF + AgCl gas Water Precipitate

Double Replacement AgNO3 + NaCl AgCl + NaNO3 ZnS + 2HCl ZnCl2 + H2S Two elements in both reactants switch places with each other AB + CD AD + CB AgNO3 + NaCl AgCl + NaNO3 ZnS + 2HCl ZnCl2 + H2S

Learning Check Classify the following as 1) Single Replacement or 2) Double Replacement ___A. 2Al + 3H2SO4 Al2(SO4)3 + 3H2 ___B. Na2SO4 + 2AgNO3 Ag2SO4 + 2NaNO3 ___C. 3C + Fe2O3 2Fe + 3CO 1 2 1