Question

K_p for the reaction, 

MgCO₃(s) → MgO(s) + CO₂(g) is 9 × 10^-10. 

Calculate ΔG⁰ for the reaction at 25°C.

Answer 1

Given : K_p = 9 x 10^-10

Temperature = T = 273 + 25 = 298 K

ΔG⁰ = ?

ΔG⁰ = -2.303 RTlog₁₀K_p

= -2.303 × 8.314 × 298 × log₁₀9 × 10^-10

= -2.303 × 8.314 × 298 × [\(\bar{10}.9542\)]

= – 2.303 × 8.314 × 298 × [ – 9.0458]

= 51683 Jmol^-1

= 51.683 kJmol^-1

∴ ΔG⁰ = 51.683 kJmol^-1