Chapter 6: Chemical Reactions and Equations Section 6.2: Types of Reactions

Objectives: Demonstrate factors that influence the direction of a reaction, Classify factors that influence the rate of a reaction

5 main types of reactions 1) Synthesis 2) Decomposition 3) Single-displacement 4) Double-displacement 5) Combustion

Synthesis SYNTHESIS : Two or more substances combine to form a single product Element/Compound + Element/Compound → Compound Example: 2Na(s) + Cl 2 (g) → 2NaCl(s) A + B → AB

Decomposition DECOMPOSITION : Compound breaks down into two or more simpler substances Compound → two or more elements/compounds Example: PCl 5 (s) → PCl 3 + Cl 2 (g) AB → A + B

Single- Displacement SINGLE-DISPLACEMENT : One element takes place of another in a compound. The element can replace the first part of a compound, or it can replace the last part of a compound. AB + C → AC + B

Single- Displacement Element a + Compound bc → Element b + Compound ac Element d + Compound bc → Element c + Compound bd Example: 2Al(s) + Fe 2 O 3 (s) → 2Fe(s) + Al 2 O 3 (s)

Double-Displacement DOUBLE-DISPLACEMENT : Positive portions of the two ionic compounds are interchanged. At least one of the products must be a precipitate or water AB + CD → AC + BD Example: PbCl 2 (s) + Li 2 SO 4 (aq) → PbSO 4 (s) + 2LiCl(aq)

Combustion COMBUSTION : A substance rapidly combines with oxygen to form one or more oxides Element/Compound + Oxygen → oxide(s) Example: CH 4 (g) + 2O 2 (g) → CO 2 (g) + H 2 O(g)