Question

Calculate \(\Delta \text{S}_{\text{total}}\) for a certain reaction at \(298\text{ K}\) if \(\Delta \text{H}^\circ = -208.6\text{ kJ}\) and \(\Delta \text{S}^\circ = -36\text{ J K}^{-1}\)

• A. \(664\text{ J K}^{-1}\)
• B. \(834\text{ J K}^{-1}\)
• C. \(926\text{ J K}^{-1}\)
• D. \(736\text{ J K}^{-1}\)

Hint:

Always convert \(\Delta H\) into Joules before calculation.

Answer 1

The Correct Option is A

Concept:
\[ \Delta S_{\text{total}} = \Delta S - \frac{\Delta H}{T} \] Step 1: Convert units. \[ \Delta H = -208600\text{ J} \]
Step 2: Substitute. \[ \Delta S_{\text{total}} = -36 - \frac{-208600}{298} \] \[ = -36 + 700 = 664 \]
Step 3: Conclusion. \[ \Delta S_{\text{total}} = 664\text{ J K}^{-1} \]