Question

Please asnwer the following question completely and correctly. Please write neatly and show all work.

1. Calculate AG (375K) for the reaction: 2CO(g) + O2(g) →202 (g) from the value of AG (298.15K) and AH (298.15K). Assume A His constant in such temperature range.

Answer 1

we have , Gibbs -Helmholtz equation :

(∂ / ∂T (ΔG /T ) = - (ΔH / T² )

on integrating between T₁ and T₂ : (assuming ΔH remains constant over range of temperature )

we get ,   ΔG_T2 /T₂ -  ΔG_T1 /T₁ =  ΔH (1/T₂ - 1/T₁ )

Our reaction :

2 CO (g) + O₂ (g) $\rightarrow$  2CO₂ (g) (question have misprinted CO₂ as O₂ )

We have, (from available sources ) Δ_rG (298.15 K ) = -257.191 kJ / mol

and Δ_rH°(298.15 K) = -283.0 kJ / mol

We need Δ_rG (375 K ) ?

putting values in equation :

Δ_rG (375 K )/ 375 K - (-257.191 kJ / mol /  298.15 K ) = (-283.0 kJ / mol ) (1/375 K - 1/ 298.15 K )

Δ_rG (375 K ) = ( 0.195   - 0.863 )kJ / mol-K * 375 K

Δ_rG (375 K ) =  -250.5 kJ / mol