2. Definitions review Reaction: A change in the arrangement of atoms or molecules by breaking bonds and forming new bonds to yield substances of different composition and properties. Element: A pure substance containing only one type of matter. Examples: Ca, F2, P4, K, Fe Compound: A pure substance consisting of two or more DIFFERENT elements bonded together. Examples: NaCl, H2O, FeCl3, C5H12 Evidence for a reaction: gas formation, heat given off or taken in, solid (precipitate) forms, color change…

3. Composition or Synthesis What does compose or synthesize mean? Basic reaction form: element 1 + element 2  compound E1 + E2  C Examples: 2 Ca (s) + O2 (g)  2 CaO (s) 1 6 Li (s) + S 8 (s)  8 Li2S (s) 2 H2 (g) + O2 (g)  2 H2O (l)

4. Decomposition What does it mean to decompose? Basic reaction form: compound  element 1 + element 2 C  E1 + E2 Examples: 2 CaO (s)  Ca (s) + 2 O2 (g) 8 Li2S (s)  1 6 Li (s) + S 8 (s) 2 H2O (l)  2 H2 (g) + O2 (g)

5. Single Replacement Review What is an element? What is a compound? Basic reaction form: compound 1 + element 1  new compound 2+ new element 2 C1 + E1  C2 + E2 Examples: NaCl (s) + K (s)  KCl (s) + Na (s) 2 Sr3N2 (s) + P4 (s)  2 Sr3P2 (s) + 2 N2 (g) F2 (g) + TiC (s)  TiF2 (s) + C (s)

6. Double Replacement Predict: How is this different from single replacement? Basic reaction form: compound 1 + compound 2  new compound 3 + new compound 4 C1 + C2  C3 + C4 Examples: NaCl (s) + KF (s)  KCl (s) + NaF (s) CaO (s) + SrCl2 (s)  CaCl2 (s) + SrO (s) Pb(NO3)2 (aq) + 2 NaI (aq)  PbI2 (s) + 2 NaNO3 (aq)

7. Combustion Everyone’s favorite reaction Burning….exploding….. Basic reaction form: fuel + oxygen  carbon dioxide + water + energy (guaranteed) fuel + O2 (g)  CO2 (g) + H2O (g) + Kj Examples: C7H16 (l) + 11 O2 (g)  7 CO2 (g) + 8H2O (g) + 4470 Kj 2 C2H5OH (l) + 7 O2 (g)  4 CO2 (g) + 6 H2O (g) + 5478 Kj 2 C 8 H 18 (l) + 25 O2 (g)  16 CO2 (g) + 18 H2O (g) + 12603 Kj

8. The 5 reaction types summary Patterns to watch for: Composition or synthesis: E1 + E2  C A + B  AB Decomposition: C  E1 + E2 AB  A + B Single Replacement: C1 + E1  C2 + E2 AB + C  AC + B Double Replacement: C1 + C2  C3 + C4 AB + CD  AD + BC Combustion:Fuel + O 2  CO 2 + H 2 O C1 + E  C2 + C3