1. Types of Chemical Reactions

2. Evidence of Chemical Reactions
Change in colour
Change in odour
Formation of a gas
Formation of a precipitate
Release or absorption of energy (e.g. heat or light)

3. Types of Chemical Reactions
We will learn about 6 types of chemical reactions
Synthesis
Decomposition
Combustion
Single Displacement
Double Displacement
Neutralization

4. Subscripts for States of Matter
We can identify the physical state of a substance using subscripts
(s) = solid
(g) = gas
(l) = pure liquid
(aq) = aqueous solution (dissolved in water)

5. Synthesis Reactions A + B  AB 2H2(g) + O2(g)  2H2O(l)
Smaller atoms/molecules combine to form larger molecules
A + B  AB
2H2(g) + O2(g)  2H2O(l)

6. Synthesis Reaction +

7. Decomposition Reaction
The splitting of a large molecule into elements or smaller molecules
AB  A + B
Complimentary to synthesis reaction
2H2O(l)  2H2(g) + O2(g)

8. Decomposition Reaction+

9. C4H10(l) + O2(g)  CO2(g) + H2O(l) + heat
Combustion
Fuel (hydrocarbons) burned in the presence of oxygen to produce a carbon dioxide, water and heat energy
CxHy + O2  CO2 + H2O + heat
C4H10(l) + O2(g)  CO2(g) + H2O(l) + heat

10. Incomplete Combustion
Occurs when fuel is not completely converted into carbon dioxide and water
Can result in the production of toxic carbon monoxide
C4H10(l) + O2(g)  C(s) + CO(g) + CO2(g) + H2O(g)
soot
poisonous

11. Mg(s) + 2AgNO3(aq)  2Ag(s) + Mg(NO3)2(aq)
Single Displacement
One element replaces another element from a compound
A + BC  AC + B
Mg(s) + 2AgNO3(aq)  2Ag(s) + Mg(NO3)2(aq)
Note: A metal can only replace a metal and a nonmetal can only replaces a nonmetal

12. Single Displacement

13. Single Displacement + +

14. The Activity Series
If the single element is above the element in the compound, a single displacement reaction will occur.

15. Examples aluminum + nickel (II) chloride lead + zinc nitrate
fluorine + sodium bromide

16. Pb(NO3)2(aq) + 2KI(aq) PbI2(s) + 2KNO3(aq)
Double Displacement
Positive ions (cations) in different compounds replace each other
AB + CD  AD + CB
Pb(NO3)2(aq) + 2KI(aq) PbI2(s) + 2KNO3(aq)

17. Double Displacement

18. Double Displacement + +

19. Solubility Rules
Most double displacement reactions involve aqueous solutions of ionic compounds
For a reaction to occur, a precipitate (insoluble solid) must form
To predict which ionic compounds will be soluble, and which will form precipitates (insoluble) we must use the solubility rules:
All compounds with nitrate (NO3-) are soluble
All compounds with ammonium (NH4+) are soluble
All compounds with group 1 metals are soluble
Most other compounds are insoluble (will form a precipitate)

20. Solubility Table
…Or use a solubility table

21. Examples sodium carbonate + barium nitrate 
lithium hydroxide + ammonium chlorate 

22. HCl(aq) + NaOH(aq)  NaCl(aq) + H2O(l)
Neutralization
A special type of double displacement reaction
Acid + Base  Salt + H2O
(ionic compound)
HCl(aq) + NaOH(aq)  NaCl(aq) + H2O(l)

23. Practice Makes Perfect!
Read p. 111, , ,
Try some problems.