Which substance has the higher entropy?
- (a) dry ice (solid CO2) at −78 °C or CO2(g) at 0 °C
- (b) liquid water at 25 °C or liquid water at 50 °C
- (c) pure alumina, Al2O3(s), or ruby (ruby is Al2O3 in which some Al3+ ions in the crystalline lattice are replaced with Cr3+ ions)
- (d) one mole of N2(g) at 1 bar pressure or one mole of N2(g) at 10 bar pressure (both at 298 K)
(a)
Interpretation: From the given substances that is dry ice at
Concept introduction: Entropy is a measure of the randomness of the system. It is a thermodynamic quantity and an extensive property. It is represented by the symbol
Answer to Problem 1PS
The substance which has the highest entropy is
Explanation of Solution
Entropy increases in the order
Hence, entropy is more for
(b)
Interpretation: From the given substances that is liquid water at
Concept introduction: Entropy is a measure of the randomness of the system. It is a thermodynamic quantity and an extensive property. It is represented by the symbol
Answer to Problem 1PS
The substance which has the highest entropy is liquid water at
Explanation of Solution
The entropy of a substance increase when the temperature is increased. At higher temperature, the substance is more disordered and thus the entropy is high. Also, when the temperature raised the additional energy added in the form of heat.
Therefore, liquid water has higher entropy at
(c)
Interpretation: From the given substances that is pure alumina and ruby the substance with higher entropy should be identified.
Concept introduction: Entropy is a measure of the randomness of the system. It is a thermodynamic quantity and an extensive property. It is represented by the symbol
Answer to Problem 1PS
The substance which has the highest entropy is Ruby.
Explanation of Solution
Thus, entropy is more for ruby than for pure
(d)
Interpretation: From the given substances that is
Concept introduction: Entropy is a measure of the randomness of the system. It is a thermodynamic quantity and an extensive property. It is represented by the symbol
Answer to Problem 1PS
The substance which has the highest entropy is
Explanation of Solution
The entropy of the system increase when the pressure is decreased. At high pressure, the substance is more ordered and the randomness is less. Thus, the entropy is less.
Thus,
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Chapter 18 Solutions
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