1. Types of Reactions

2. Types of Reactions Synthesis Decomposition Single-Replacement
Double-Replacement

3. 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.

4. 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

5. 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

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

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

8. 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

9. 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 ZnCl H2
Fe CuSO4 FeSO4 + Cu

10. 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

11. 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 HCl ZnCl2 + H2S

12. 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