1. Types of Reactions

2. There are so many different reactions that happen inside and outside the human body that chemists have tried to organize them into 5 major groups

3. Synthesis Reactions Two or more substances combine to form a more complex substance (synthesis) 2 or more reactants Only one product

4. Synthesis reactions A + B AB

5. Synthesis Reactions A and B may be elements or compounds AB is always a compound N 2 + 3H 2 2NH 3 Produces ammonia to be used in many things, like fertilizer, nylon and plastic.

6. Examples 2Mg + O 2 → 2MgO S + O 2 → SO 2 2Na + Cl 2 → 2NaCl

7. Decomposition Reactions A complex substance breaks down into simple substances (opposite of synthesis) 2 or more products Only 1 reactant.

8. Decomposition reactions AB A + B

9. Decomposition Reactions AB is always a compound A & B may be elements or compounds 2HgO Hg + O 2 Bleaching hair, antiseptic, rocket fuel

10. Examples 2HgO → 2Hg + O 2 CaCO 3 → CaO + CO 2

11. Single Replacement Reactions An uncombined element replaces another element that is in a compound. 1 of the reactants must be an uncombined element and the other an ionic compound. 1 of the products must be an uncombined element and the other an ionic compound.

12. Single Replacement Reactions A + BC AC + B

13. Single Replacement Reactions Zn + H 2 SO 4 ZnSO 4 + H 2

14. Double Replacement Reactions Two compounds exchange positive ions. All reactants and products are ionic. Will only occur if at least 1 compound is removed from solution. by precipitation One product is water One product is a gas that bubbles away

15. Double Replacement Reactions AB + CD AD + CB

16. Double Replacement Reactions 2NaOH + H 2 SO 4 Na 2 SO 4 + 2HOH

17. Combustion Reactions A substance burns in the presence of oxygen to produce carbon dioxide and water. C 3 H 8 + 5 O 2  3 CO 2 + 4H 2 O Propane burns (with the help of oxygen) to produce carbon dioxide and water

18. Combustion Reaction Be careful not to confuse combustion reactions with single replacement reactions.

19. Let’s practice!!!!! 3Mg + 2FeCl 3  2Fe + 3MgCl 2 2Fe + 3F 2  2FeF 3 SO 3 + H 2 O  H 2 SO 4 2HI  H 2 + I 2 Li 2 CrO 4 + BaCl 2  2LiCl + BaCrO 4 CH 4 + 2O 2  CO 2 + 2H 2 O 2Al 2 O 3  4Al + 3O 2