1. Types of Reactions (7.2)

2. Classifying Reactions
Reactions are often classified by the type of reactant or the number of reactants and products
Each type of reaction describes a different way in which reactants interact to form products

3. Synthesis Reactions
Two or more substances react to produce a single product
A + B --> AB

4. Can occur between two elements:
2Na (s) + Cl2 (g) --> 2NaCl (s)
Can occur between two compounds:
CaO (s) + H2O (l) --> Ca(OH)2 (s)

5. Can occur between a compound and an element:
2SO2 (g) + O2 (g) --> 2SO3 (g)

6. Combustion Reactions
When oxygen combines with another substance and releases energy in the form of heat and light

7. Example - burning of coal:
C (s) + O2 (g) --> CO2 (g)

8. Decomposition Reactions
When a single compound breaks down into two or more elements or new compounds
Often requires an energy source such as heat, light, or electricity to occur

9. AB --> A + B
Example:
NH4NO3 (s) --> N2O (g) + 2H2O (g)

10. Single Replacement Reactions
The atoms of one element replace the atoms of another element in a compound
A + BX --> AX + B

11. Three types of single replacement reactions Metal replacing hydrogen:
2Li (s) + 2H2O (l) --> 2LiOH (aq) + H2 (g)

12. Metal replacing another metal:
Cu(s) + 2AgNO3(aq) --> Cu(NO3)2(aq) + 2Ag(s)

13. Non-metal replacing another non-metal:
F2 (g) + 2NaBr (aq) --> 2NaF (aq) + Br2 (l)

14. Double Replacement Reactions
Involves the exchange of ions between two compounds
AX + BY --> AY + BX

15. The (+) and (-) ions of two compounds switch places
Example:
Ca(OH)2(aq) + 2HCl(aq) --> CaCl2(aq) + 2H2O(l)
2NaOH(aq) + CuCl2(aq) --> 2NaCl(aq) + Cu(OH)2(s)
The (+) and (-) ions of two compounds switch places

16. The (+) and (-) ions of two compounds switch places
Identify the cations and anions in each compound, then pair up each cation with an anion from the other compound
Double replacement reactions form a precipitate (solid), a gas, or water