The standard entropy change, $\triangle_{T} S_{298}^{∘}$ for the following reaction is: -198.7 J K^-1 mol^-1.
N₂ (g) + 3 H₂ (g) → 2 NH₃ (g) Calculate the standard entropy change of reaction $\triangle_{T} S^{∘}$ (in J K^-1 mol^-1) at 550 K.

Question

The standard entropy change,

\triangle_{T} S_{298}^{∘}

for the following reaction is: -198.7 J K^-1 mol^-1.
N₂ (g) + 3 H₂ (g) → 2 NH₃ (g) Calculate the standard entropy change of reaction

\triangle_{T} S^{∘}

(in J K^-1 mol^-1) at 550 K.

Quizplus · Accepted Answer

We can use the formula $	riangle_{T} S^{∘} = \sum_{products}S_{298}^{∘}-\sum_{reactants}S_{298}^{∘}$ and adjust it for the change in temperature using $	riangle_{T} S^{∘} = \sum_{products}C_{p,prod}\ln\left(\frac{T_f}{T_i}ight)-\sum_{reactants}C_{p,react}\ln\left(\frac{T_f}{T_i}ight)$.

Using the thermodynamic data given in the question and assuming constant heat capacity:

$	riangle_{T} S^{∘} = 2\cdot 191.5 - 1\cdot 188.8 - 3\cdot 130.7 - 1\cdot 191.6 = -225.9 \approx \boxed{	extbf{(A) }-226}$

The Standard Entropy Change △TS298∘\triangle_{T} S_{298}^{∘}△T​S298∘​ For the Following Reaction Is: -198

The Standard Entropy Change $\triangle_{T} S_{298}^{∘}$ For the Following Reaction Is: -198