Thermodynamics and Thermochemistry 1 Question 30
33. Spontaneous adsorption of a gas on solid surface is an exothermic process because
(2004, 1M)
(a) $\Delta H$ increases for system
(b) $\Delta S$ increases for gas
(c) $\Delta S$ decreases for gas
(d) $\Delta G$ increases for gas
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Solution:
- For a spontaneous process $\Delta G<0$
Also; $\Delta G=\Delta H-T \Delta S$
For adsorption of gas on solid surface, $\Delta S<0$. Therefore, in order to be $\Delta G<0, \Delta H$ must be negative.
