Question

Write applications of standard molar entropy.

Answer 1

Hint: Entropy is a state function of any system. It is only depending upon the initial and final state of the system throughout a process, but does not depend upon the pathway of the process. \[\Delta S\] is a change of entropy.

Complete step by step answer:
This concept of entropy is used to measure the spontaneity of any process or change of the system. According to the second law of thermodynamics for an isolated system (no exchange of heat or mass with the surroundings) the reversible process always proceeds to increase the entropy. Therefore, from this law, it is concluded that any process would be spontaneous if the entropy is increasing through that process. For example, the melting of ice is a spontaneous process, as due to the melting of ice entropy of the system increases.
The applications of standard molar entropy are,
Standard molar entropy change can be calculated by knowing the standard molar entropy of all products and reactants in a reaction. By using the formula \[\Delta {S^0} = \sum m {S^O}(products) - \sum n {S^O}(reac\tan ts)\]. Where m and n are the coefficient of the reactant and product.
Standard molar entropy is useful to compare the entropy of different substances. The molar entropy value increases with increasing the complexity of the molecule. For example, \[C{H_3}COOH\] is more complex than \[C{H_3}OH\]. So, Standard molar entropy is greater for \[C{H_3}COOH\] than that of \[C{H_3}OH\]. The Standard molar entropy is also greater for heavier substances than a lighter one.

Note:
When the entropy of the final state of any process is higher than the initial state, the change of entropy .i.e. \[\Delta S\] becomes positive. And when the entropy of the final state of any process is lower than the initial state, the change of entropy .i.e. \[\Delta S\] becomes negative.
Now the change of entropy indicates the change of disorders of the randomness of the system.
So, if the change of entropy (\[\Delta S\]) is positive then the system becomes more disordered.