Section 2: Redox Reactions A. Redox Rxns B. Redox in Living Systems

A. Redox Rxns Redox Rxns: oxidation-reduction reactions involving the transfer of electrons (e- loss & e- gain) OILRIG

A. Redox Rxns used to be gaining oxygen 2 Fe(s) + 3 O2(g) → Fe2O3(s)

A. Redox Rxns

A. Redox Rxns

CH4(g) + 2O2(g) → CO2(g) + H2O(g) A. Redox Rxns -4 +1 +4 -2 +1 -2 CH4(g) + 2O2(g) → CO2(g) + H2O(g) Oxidized? (charge ↑) Reduced? (charge ↓)

NOT REDOX because… (NO e- loss or gain) A. Redox Rxns 2NaF(aq) -1 +2 -1 +1 +1 -1 +2 -1 2NaF(aq) + CaCl2(aq) → 2NaCl(aq) + CaF2(s) Oxidized? (charge ↑) Reduced? (charge ↓) NOT REDOX because… NO charges changed (NO e- loss or gain)

water (H2O) is oxidized to oxygen (O2) B. Redox in Living Systems Photosynthesis water (H2O) is oxidized to oxygen (O2) +4 -2 +1 -2 +1 -2 6CO2 + 6H2O → C6H12O6 + 6O2 carbon dioxide (CO2) is reduced to glucose (C6H12O6)

B. Redox in Living Systems Cellular Respiration C6H12O6 is oxidized to CO2 +1 -2 +4 -2 +1 -2 C6H12O6 → 6CO2 + 6O2 + 6H2O O2 is reduced to H2O

Quick Quiz! 1. During oxidation, an element _______ electrons. During reduction, an element ________ electrons. gains, loses loses, gains gains, donates gains, accepts

Quick Quiz. 2. Which element is reduced in the following chemical reaction? Fe2O3 + 3 CO  2 Fe + 3 CO2 O Fe C none (not redox) -2 +2 -2 +3 +4 -2