Hydrogen bromide dissociates into its gaseous elements, H2 and Br2, at elevatedtemperatures.AH;, kJ/mol S° , J/(mol-K)HBr(g)-36.44198.6H2 (9)130.6Bra(9)30.91245.3a. Calculate the percent dissociation at 337°C and 1.00 atm.(Enter your answer to three significant figures.)Percent dissociation%b. What would be the percent dissociation at 337°C and 10.0 atm?(Enter your answer to three significant figures.)Percent dissociation]%c. Use data above and any reasonable approximation to obtain K.(Enter your answer to three significant figures.)K

The equilibrium constant can be written as the ratio of concentration of products to the concentration of reactants raised to some power of their stoichiometric coefficient. It is represented by Keq or Kp or Kc.The reaction is shown below:2 HBr → H2 + Br2The calculation of change in enthalpy is shown below: ΔH(reaction) = ΔH(products) - ΔH(reactants) =ΔHH2 +ΔHBr2 -2×∆HHBr= 0 + 30.91 - 2×(-36.44) = 103.79 kJ/mol = 103790 J/mol The calculation of change in entropy is shown below: ΔS(reaction) = ∆S(products) - ∆S(reactants) =∆SH2 +∆SBr2 -2×∆SHBr= 245.3 + 130.6 - 2 ×198.6 = -21.3 J/molThe calculation of change in Gibb's free energy is shown below: Temperature = 337 0C = 610 K ΔG(reaction) = ΔH(reaction) - TΔS(reaction) = 103790 - 610 ×(-21.3) = +116783 J/mol The calculation of value of K is shown below: ΔG(reaction) = -RT ln K 116783 = -8.314 × 610 × ln K K = exp(-23.03) = 9.96×10-11Initial Pressure(HBr) = 1 atm At equilibrium, Pressure(H2) = Pressure(Br2) = a Pressure(HBr) = 1 - 2a The calculation of value of a is shown below: K = P(H2)P(Br2)P(HBr)2 9.96×10-11= a2(1 - 2a)2 a = 0.998 × 10-5The calculation of percent dissociation at 1 atm is shown below: Percent dissociation = 2a1 × 100 = 1.99x 10-3%Initial Pressure(HBr) = 10 atm At equilibrium, Pressure(H2) = Pressure(Br2) = a Pressure(HBr) = 10 - 2a The calculation of value of a is shown below: K = P(H2)P(Br2)P(HBr)2 9.96× 10-11= a2(10 - 2a)2 a = 0.998 x 10-4The calculation of percent dissociation at 10 atm is shown below: Percent dissociation = 2a10× 100 = 1.99×10-3 %