2. Types of Chemical Reactions

3. Types of Reactions There are six types of chemical reactions we will talk about: 1. 1. Synthesis reactions (syn) 2. 2. Decomposition reactions (decomp) 3. 3. Single replacement reactions (SR) 4. 4. Double replacement reactions (DR) 5. 5. Combustion reactions (Comb) 6. 6. Oxidation-Reduction reactions (Redox)

4. Synthesis Reactions Synthesis Reactions (AKA Combination or Addition) Two substances (generally elements) combine and form a compound. reactant + reactant 1 product A + B AB 2H 2 + O 2 2H 2 O C + O 2 CO 2

5. Synthesis Reactions

6. Decomposition Reactions Compound breaks up into the elements or into a few simpler compounds 1 Reactant Product + Product AB A + B 2 H 2 O 2H 2 + O 2 2 HgO 2Hg + O 2

7. Decomposition Reactions

8. Single Replacement or Displacement Reactions One element replaces another in a compound metal can replace a metal (+) OR nonmetal can replace a nonmetal (-) element + compound product + product A + BC AC + B (if A is a metal) OR A + BC BA + C (if A is a nonmetal) (remember the cation always goes first!)

10. Single Replacement Reactions

11. Sodium chloride solid reacts with fluorine gas NaCl (s) + F 2(g) NaF (s) + Cl 2(g) Note that fluorine replaces chlorine in the compound Aluminum metal reacts with aqueous copper (II) nitrate Al (s) + Cu(NO 3 ) 2(aq) Cu (s) + Al(NO 3 ) 3(aq) 22 23 3 2

12. 4. Double Replacement Reactions Double Replacement Reactions occur when a metal replaces a metal in a compound and a nonmetal replaces a nonmetal in a compound Compound + compound product + product AB + CD AD + CB

13. Double Replacement Reactions Think about it like foiling in algebra, first and last ions go together + inside ions go together Example: AgNO 3(aq) + NaCl (s) AgCl (s) + NaNO 3(aq) Another example: K 2 SO 4(aq) + Ba(NO 3 ) 2(aq) KNO 3(aq) + BaSO 4(s) 2

14. 5. Combustion Reactions Combustion reactions occur when a hydrocarbon reacts with oxygen gas. This is also called burning!!! In order to burn something you need the 3 things in the fire triangle: 1) A Fuel (hydrocarbon) 2) Oxygen to burn it with 3) Something to ignite the reaction (spark)

15. Combustion Reactions In general: C x H y + O 2 CO 2 + H 2 O Products in combustion are ALWAYS carbon dioxide and water. (although incomplete burning does cause some by- products like carbon monoxide) Combustion is used to heat homes and run automobiles (octane, as in gasoline, is C 8 H 18 )

16. Combustion Reactions Edgar Allen Poes drooping eyes and mouth are potential signs of CO poisoning.

17. Combustion Example C 5 H 12 + O 2 CO 2 + H 2 O Write the products and balance the following combustion reaction: C 10 H 22 + O 2 5 6 8 CO 2 + H 2 O10 11 2 312022

18. Oxidation-Reduction Many of these 5 types of reactions are also oxidation-reduction reactions Many of these 5 types of reactions are also oxidation-reduction reactions Oxidation: Loss of electrons Oxidation: Loss of electrons Reduction: Gain of electrons Reduction: Gain of electrons

19. You cant have one… without the other! Reduction (gaining electrons) cant happen without an oxidation to provide the electrons. Reduction (gaining electrons) cant happen without an oxidation to provide the electrons. You cant have 2 oxidations or 2 reductions in the same equation. Reduction has to occur at the cost of oxidation You cant have 2 oxidations or 2 reductions in the same equation. Reduction has to occur at the cost of oxidation LEO the lion says GER! o s e l e c t r o n s x i d a t i o n a i n l e c t r o n s e d u c t i o n GER!

20. Another way to remember OIL RIG OIL RIG x i d a t i o n s o s e e d u c t i o n s a i n

21. Mixed Practice State the type and balance the following reactions: 1. 1. BaCl 2 + H 2 SO 4 2. 2. C 6 H 12 + O 2 3. 3. Zn + CuSO 4 4. 4. Cs + Br 2 5. 5. FeCO 3 BaSO 4 + HCl2 CO 2 + H 2 O 66 9 ZnSO 4 + Cu CsBr22 FeO + CO 2