810. 6 Photochemistry It-class reading Levine, pp. 800-804 photochemistry
§10. 6 Photochemistry Out-class reading: Levine, pp. 800-804 photochemistry
§10.6 Photochemistry 6.5 Quantum yield and energy efficiency Quantum yield or quantum efficiency(p) ForH2+Cl2→2HClΦ=104~10 For h+ Br.->2HBr =0.01 gp>l initiate chain reaction The ratio between the number of moles of reactant consumed or product a=1, product is produced in primary formed for each Einstein of absorbed photochemical process radiation g< l, the physical deactivation is d minar
6.5 Quantum yield and energy efficiency Quantum yield or quantum efficiency (): The ratio between the number of moles of reactant consumed or product formed for each Einstein of absorbed radiation. a n r I = = For H2+ Cl2→ 2HCl = 104 ~ 106 For H2+ Br2→ 2HBr = 0.01 > 1, initiate chain reaction. = 1, product is produced in primary photochemical process < 1, the physical deactivation is dominant §10. 6 Photochemistry
§10.6 Photochemistry 6.5 Quantum yield and energy efficiency Photosynthesis: Energy efficiency: 6C0,+6H,O+nhy->CHoE+6O Light energy preserved Total light energy △G=2870 kJ mol For formation of a glucose, 48 light quanta was needed 2870 35.79 48×167.4
Energy efficiency: Photosynthesis: 6CO2 + 6H2O + nh → C6H12O6 + 6O2 rGm = 2870 kJ mol-1 For formation of a glucose, 48 light quanta was needed. 35.7% 48 167.4 2870 = = 6.5 Quantum yield and energy efficiency §10. 6 Photochemistry
§10.6 Photochemistry 6.6 The way to harness solar energy--photosynthesis 6C02+6H20+ nhy>C6H12 06+602 Porphyrin complex with magnesium Light harvesting protein Photosensitive reaction Reaction initiated by photosensitizer When reactants themselves do not Central chlorophyll eaction cente of reaction center absorb light energy, photosensitizer can be used to initiate the reaction by conversion o of the light energy to the Light harvesting protein reactants Chlorophyll A, B, C, and D
Photosensitive reaction Reaction initiated by photosensitizer. 6CO2 + 6H2O + nh → C6H12O6 + 6O2 When reactants themselves do not absorb light energy, photoensitizer can be used to initiate the reaction by conversion of the light energy to the reactants. Chlorophyll A, B, C, and D Porphyrin complex with magnesium 6.6 The way to harness solar energy—photosynthesis §10. 6 Photochemistry
§10.6 Photochemistry 6.6 The way to harness solar energy Light reaction: the energy content of the light quanta is converted into chemical energy Dark reaction: the chemical energy was used to form glucose 4Fd3++3ADP3-+3P28 4Fd2++ 3ATP4-+0,+Ho+H+ fd is a protein with low molecular weight 3ATP3-+4Fd2+C0,+Ho+H+ 3P2 >(CH2O)+3ADP3+3P2+4Fd3+
Light reaction: the energy content of the light quanta is converted into chemical energy. Dark reaction: the chemical energy was used to form glucose. Fd is a protein with low molecular weight 4Fd3+ + 3ADP3- + 3P2- ⎯→ 4Fd2+ + 3ATP4- + O2 + H2O + H+ 3ATP3-+ 4Fd2++ CO2+ H2O + H+ 3P2- → (CH2O) + 3ADP3- + 3P2- + 4Fd3+ 8h 6.6 The way to harness solar energy §10. 6 Photochemistry