Chemical Thermodynamics Question 265
Question: For the reaction $ CO(g)+\frac{1}{2}O_2(g)\xrightarrow{{}}CO_2(g),\Delta H $ , and $ \Delta S $ are $ -283kJ $ and $ -87J{{K}^{-1}} $ , respectively. It was intended to carry out this reaction at 1000, 1500, 3000 and 3500 K. At which of these temperatures would this reaction be thermodynamically spontaneous-
Options:
A) 1500 and 3500 K
B) 3000 and 3500 K
C) 1000, 1500 and 3000 K
D) 1500, 3000 and 3500 K
Show Answer
Answer:
Correct Answer: C
Solution:
$ \therefore \Delta G=\Delta H-T\times \Delta S $ For a spontaneous reaction, $ \Delta G $ should be negative $ \Delta H=-238kJ,\Delta S=-87J/K $
Hence, reaction will be spontaneous when $ \Delta S>\frac{\Delta H}{T} $ . Therefore, at 1000, 1500 and 3000 K the reaction would be spontaneous.
BETA
