Using the data in Appendix 2, calculate the standard entropy changes for the following reactions at
Interpretation:
The standard entropy change for the given reactionis to be calculated.
Concept introduction:
Entropy is the direct measurement of randomness or disorderness. Entropy is an extensive property. It is a state function.
Entropy of a system is a measure of how spread out or how dispersed the system’s energy is. Entropy change of a system is the difference between the entropy of the final state and the entropy of theinitial state.
The entropy of the system and the entropy of the surroundings make up the entropy of the universe.
Entropy change of the reaction is the difference between the entropies of the reactants and products.
Mathematically, the entropy change can be represented as follows:
Here,
Answer to Problem 15QP
Solution:
a)
b)
c)
Explanation of Solution
a)
The standard entropy change for this reaction is calculated using the expression as follows:
Here,
From Appendix 2, the standard entropy value of the substance is as follows:
Substitute,
Therefore, the standard entropy change for this reaction is
b)
The standard entropy change for the reaction is calculated using the expression as follows:
Here,
The entropy change for the reaction is calculated by the expression as follows:
From Appendix
Substitute,
Therefore, the standard entropy change for this reaction is
c)
The standard entropy change for this reaction is calculated using the expression as follows:
Here,
From Appendix 2, the standard entropy value of the substance is as follows:
Substitute,
Therefore, the standard entropy change for this reaction is
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Chapter 18 Solutions
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