Question

2. (10 pts) Combustion of coal is the main source of electricity in the world now. Since coal is mostly made of carbon, the combustion process may be approximated by the following equation. C(s) + O2(g) CO2(g) (rxn 2) Its equilibrium constant at 25°C may be calculated from thermodynamic data as 1.25 x 1069 a) (2 pts) Does this value apply to Kp or Kor both? Explain briefly. b) (4 pts) If 1.00 mol of carbon is combined with 0.50 mol of oxygen gas in a 1.00 L vessel and the equilibrium of the above reaction is achieved, what are the equilibrium concentrations in mol/L) of the O2 and CO2 gases? Assume that no carbon monoxide forms. c) (4 pts) If 0.50 mol of C(s) is combusted in 1.00 mol O2(g) in a 1.00 L vessel, what are the final concentrations of O2(g) and CO2(g)? Does the final state of the system correspond to the equilibrium of rxn (2)? Explain briefly.

Answer 1

a) kp & Ke both are same, as or Ang= Enpood - I noreact = 0 L Kp=ke b) Cess & O2 ig) - CO₂ (g) to II 0.5 W At eq. co c o 0.5-6. 0.62€ 1.25X1069 c<< 0.5 lik is too high)
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o 5 : 1 25 х»o69 c: 5 x 10:43 co, j = чxio-70 м [co, i о. 5 м

a Gesi & Ozeg, CO₂ (g) t=0 0.5 1 Carbon is limiting reagent. [0₂] = 0.5 [CQ]= 0.5 This state does not corusbond to equilibrium state because reaction does not reach equilibrium dul to insufficient amount of carbon.