1. Thanksgiving Gifts from Photosynthesis OR Nature’s Chemistry at It’s Best

2. Thanksgiving Gifts from Photosynthesis Have a great Thanksgiving holiday!

3. Section 8.2 Other Reactions in Aqueous Solutions Sections 8.2-8.3 1.identify various types of chemical reactions 2.identify the processes and driving forces behind different types of reactions 3.Write equations for different types of reactions Learning Goals – I will be able to…

4. Section 8.2 Other Reactions in Aqueous Solutions Sections 8.2-8.3 Formation of a Solid Precipitation, a Double Displacement Reaction (covered in 8.1) General equation: AB + CD  AD + CB Precipitation reaction Double displacement/replacement reaction

5. Section 8.2 Other Reactions in Aqueous Solutions Sections 8.2-8.3 Formation of Water: Acids and Bases (not in notes): A different type of double replacement reaction A strong acid is one in which virtually every molecule dissociates (ionizes) in water to an H + ion and an anion.

6. Section 8.2 Other Reactions in Aqueous Solutions Sections 8.2-8.3 A strong base is a metal hydroxide that is completely soluble in water, giving separate OH  ions and cations. Formation of Water: Acids and Bases (not in notes) –Most common  NaOH, KOH

7. Section 8.2 Other Reactions in Aqueous Solutions Sections 8.2-8.3 Formation of Water: Acid-Base Reaction, a Double Replacement Reaction (not in notes) The products of the reaction of a strong acid and a strong base are water and a salt. Net ionic equation H + (aq) + OH − (aq)  H 2 O(l) Reaction of H + and OH − is called an acid-base reaction. H +  acidic ion OH −  basic ion The other anion/cation pair forms a Salt (Ionic compound) * NOTICE THAT IF THE PROPER AMOUNTS OF ACID AND BASE ARE MIXED THE PH OF THE SOLUTION WILL BECOME NEUTRAL. *

8. Section 8.2 Other Reactions in Aqueous Solutions Sections 8.2-8.3 Acids and bases are both ionic compounds  strong acids/bases are strong electrolytes. Acids produce H+ ions in water. Bases produce OH- ions in water. Water is a very stable compound  strong tendency for reaction to happen. Acid + Base  Water + Salt HCl (aq) + NaOH (aq)  H 2 O (l) + NaCl (aq) Net Ionic Equation: H+(aq) + OH−(aq)  H 2 O(l) Formation of Water: Acid-Base Reaction, a Double Replacement Reaction (notes summary)

9. Section 8.2 Other Reactions in Aqueous Solutions Sections 8.2-8.3 Transfer of Electrons -- Reactions of Metals with Nonmetals (Oxidation-Reduction) Reactions between metals and nonmetals involve a transfer of electrons from the metal to the nonmetal. Oxidation–reduction reaction (redox)

10. Section 8.2 Other Reactions in Aqueous Solutions Sections 8.2-8.3 Transfer of Electrons: Oxidation-Reduction Reactions A metal and a nonmetal combine to form an ionic compound. Ex.: 2Na (s) + Cl 2(g)  2NaCl (s) Electron transfer: –sodium is “oxidized”  loses one electron –chlorine is “reduced”  gains one electron

11. Section 8.2 Other Reactions in Aqueous Solutions Sections 8.2-8.3 Single Replacement – One Ion Replaced Driving force: –Transfer of electrons General equation: A + BC  B + AC

12. Section 8.2 Other Reactions in Aqueous Solutions Sections 8.2-8.3 Single Replacement Reaction – One Ion Replaced (another example) Driving forces: –Transfer of electrons –Formation of a Gas

13. Section 8.2 Other Reactions in Aqueous Solutions Sections 8.2-8.3 Involve oxygen & produce a flame (energy released rapidly) CH 4 (g) + 2O 2 (g)  CO 2 (g) + 2H 2 O(g) Combustion Reactions Types of Oxidation-Reduction Reactions (Redox) A compound forms from simpler materials C(s) + O 2 (g)  CO 2 (g) Synthesis (Combination) Reactions A compound is broken down into simpler substances 2H 2 O(l)  2H 2 (g) + O 2 (g) Decomposition Reactions Single Replacement (seen before) – new ion forms

14. Section 8.2 Other Reactions in Aqueous Solutions Sections 8.2-8.3 Ways to Classify Reactions (notes summary) Precipitation – a solid forms Double Replacement (Displacement) – two ions exchanged/replaced Ex.: acid-base, precipitation Single Replacement – one ion replaced Combustion – energy is released, flame; oxygen is a reactant Synthesis – reactants combine to form product(s) Decomposition – reactant breaks down into products * Refer to reaction sheet to see examples. * *REDOX REACTIONS*