1. Chemical Reactions

2. Reactants Products Produce Chemical equation used to describe Chemical Reactions

3. Symbols in chemical reactions (s) Solid (l) Liquid (g) Gas (aq)Aqueous,solid dissolved in water Produces or yields

4. Burning of Charcoal C (s)+ O 2 (g) Carbon + OxygenCarbon Dioxide CO 2 (g) Simplified to:

5. Antoine Lavoisier Law of conservation of mass: Mass neither lost nor gained during a chemical reaction –Mass products = mass reactants

6. Balancing Chemical Equations Atoms of Reactants and Products must be balanced to satisfy law conservation of mass

7. Types of Reactions

8. Synthesis: two or more Substances react to form a Single substance A + B Ex: 2H 2 (g) + O 2 (g) AB 2H 2 O (l)

9. Synthesis of Water An explosive reaction!

10. Decomposition: Compound breaks Down into two or more simpler Substances AB A + B Ex: 2H 2 O (l) H 2 (g) + O 2 (g) electricity

11. Electrolysis of water O 2 gas H 2 gas

12. Single Replacement : “ partner stealing ” One element takes the place of another Element in a compound A + BC B + AC Cu + 2AgNO 3 2Ag + Cu(NO 3 ) 2

13. Double Displacement: “ partner swapping ” Two different compounds exchange Positive ions and form two new compounds (+) AB + CD AD + BC Pb(NO 3 ) 2 + 2 KI PbI 2 + 2KNO 3 DD reactions usually form a gas or a precipitate

14. Combustion: Substance reacts rapidly with oxygen always producing heat, carbon dioxide and water CH 4 + 2O 2 CO 2 + 2H 2 O Methaneoxygencarbon dioxide water

15. Energy and Chemical Reactions

16. Chemical Reactions In all chemical reactions: Energy is either: 1. Released 2. Absorbed

17. Exothermic Reactions Produces heat (feels warm) –More energy is released as products form, than is required to break bonds in reactants

18. Endothermic Reactions Reaction uses more heat than it gives off (feels cold) –more energy is required to break bonds than to form new ones

19. Reaction Rates

20. Reaction Rate How fast a reaction is occurring –Increased rate = fast –Decreased rate = slow

21. 5 Factors Affecting Reaction Rate 1. Temperature: –Higher temp. = faster reaction

22. 2. Surface area Increasing surface area (crush into smaller pieces) = faster reaction rate

23. 3. Concentration of Reactants Increasing concentration = faster reaction rate

24. 4. Use of Catalyst Catalyst: substance that speeds up a chemical reaction without being consumed

25. 5. Stirring Stirring increases reaction rate Stirrer used in industry