KVPY2020ChemistryChemical Equilibrium
The reaction CaCO 3 s ⇌ CaO s + CO 2 g is in equilibrium in a closed vessel at 298   K . The partial pressure (in atm) of CO 2 g in the reaction vessel is closest to: [Given: The change in Gibbs energies of formation at 298   K and 1 bar for CaO ( s ) = - 603 . 501   kJ   mol - 1 CO 2 g = - 394 . 389   kJ   mol - 1 CaCO 3 s = - 1128 . 79   kJ   mol - 1 Gas constant R = 8
Options
- A1 . 13 × 10 - 23
- B0 . 95
- C1 . 05
- D8 . 79 × 10 23
Correct answer
A. 1 . 13 × 10 - 23
Step-by-step solution
CaCO 3 ( s ) ⇌ CaO ( s ) + CO 2 ( g ) Δ r G 0 = Δ f G 0 ( CaO ) + Δ f G 0 CO 2 - Δ f G 0 CaCO 3 = - 603 . 501 - 394 . 389 + 1128 . 79 = 130 . 9   kJ   mol - 1 Δ r G 0 = - 2 . 303 RTlogK P logK p = 130 . 9 × 1000 - 2 . 303 × 298 × 8 . 314 = - 22 . 94 K p = antilog ( - 22 . 94 ) = 1 . 13 × 10 - 23