1 1 Q=- .Pi1.30W3.00=0.0855 E°=1.229V R=8.314 JK*mol' T=50℃=323K N=4 mol e" F=96487 C(mol e) Thus, E-RIm(Q)-129JC 8.314JK-'mol(323K) nF 4mole(96487C(mole(00855) =1.229JC--(-0.0173JC-) =1.246JC =1.246V 2.Using the following data,calculate the value of AHrof H2O →H0gl △H°=-241.8kJmo AH= -92 5.9 kJ mol 2Hg)+20g→H02g △H°=-1070.6 kJ mol 20g→02g △H=-498.3 kJ mol H00→H02xg △H=51.5 kJ mol We want AH°for the reaction H2e+O2gl→H,O2 H202g)→H2020 △H°=-51.5 kJ mol 2Hg,+20g→H02g △H=-1070.6kJmo h02g→0gl △H=(498.3)kJmo H,0g→2Hg+0g AH=-(-926 9)kI mol H2g+hO2e→H2Og △H°=-241.8 kJmol" H2e+O2e→H202D AH=-187.85 kJ mol 3 Calculate the pH and the concentrations of all species present(except water)in a 1.0 M solution of phosphorous acid,H;PO)For this acid,Ka=1.0 x 102and Ka2=2.6x 10.(The third proton is not acidic.) H3POxag+H2O-H3O'+H2PO3(Q) 33 2 2 2 2 O H 1 1 Q 0.0855 p p (1.30)(3.00) == = E0 = 1.229 V R = 8.314 J K-1mol-1 T = 50o C = 323 K N = 4 mol e- F = 96487 C (mol e- ) -1 Thus, 1 1 0 1 1 1 1 1 RT 8.314JK mol (323K) E E ln(Q) 1.229 J C ln(0.0855) nF 4 mole (96487 C(mole ) ) 1.229J C ( 0.0173J C ) 1.246J C 1.246V − − − − − − − − − =− = − = −− = = 2. Using the following data, calculate the value of ΔHo f of H2O2(l): H2(g) + ½ O2(g) → H2O(g) ΔHo = −241.8 kJ mol-1 2 H(g) + O(g) → H2O(g) ΔHo = −926.9 kJ mol-1 2 H(g) + 2O(g) → H2O2(g) ΔHo = −1070.6 kJ mol-1 2 O(g) → O2(g) ΔHo = −498.3 kJ mol-1 H2O2(l) → H2O2(g) ΔHo = 51.5 kJ mol-1 We want ΔHo for the reaction H2(g) + O2(g) → H2O2(l) H2O2(g) → H2O2(l) ΔHo = -51.5 kJ mol-1 2 H(g) + 2 O(g) → H2O2(g) ΔHo = -1070.6 kJ mol-1 ½ O2(g) → O(g) ΔHo = ½(498.3) kJ mol-1 H2O(g) → 2 H(g) + O(g) ΔHo = -(-926.9) kJ mol-1 H2(g) + ½ O2(g) → H2O(g) ΔHo = -241.8 kJ mol-1 __________________________________________________ H2(g) + O2(g) → H2O2(l) ΔHo = -187.85 kJ mol-1 3. Calculate the pH and the concentrations of all species present (except water) in a 1.0 M solution of phosphorous acid, H3PO3(aq). For this acid, Ka1 = 1.0 x 10-2 and Ka2 = 2.6 x 10-7. (The third proton is not acidic.) H3PO3(aq) + H2O(l) ⎯ H3O+ (aq) + H2PO3 - (aq)