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Grade upto college level Physical Chemistry

Show that the reaction CO(g) + 1/2 O2(g) → CO2 (g) at 300 K, is spontaneous and exothermic, when the standard entropy change is4.094 kJ mol-l K-l. The standard Gibbs free energies of formation for CO2 and CO are -394.4 and, -137.2kJ mol-I, respectively.

Profile image of Shane Macguire
12 Years agoGrade upto college level
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1 Answer

Profile image of Deepak Patra
12 Years ago
Hello Student,
Please find the answer to your question
For following reaction
CO(g) + 1/2 O2(g) → CO2(g)
∆G° can be calculated as follows :
∆G° = ∆Gp° - ∆G°R = [∆G°CO2 – (∆G°CO + 1/2 ∆G°O2)]
= - 394.4 – (- 137.2 + 1/2 * 0) = - 257.2 kJ mol-1
Since,
∆G° = ∆H° - T∆S° or -257.2 = ∆H – 300(0.094)
∴ ∆H° = - 285.4 kJ/mol
Since,
NOTE : ∆H° is negative, so the reaction is exothermic and since ∆G° is negative so the reaction is spontaneous.

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jitender
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