State the second law of thermodynamics.

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The second law of thermodynamics is a fundamental principle that describes the direction of thermodynamic processes and the concept of entropy.

Entropy is a measure of the disorder or randomness in a system, and the second law states that the total entropy of an isolated system can never decrease over time.

In practical terms, this means that natural processes tend to move towards a state of maximum entropy or disorder.

The second law also implies that energy transformations are not 100% efficient, as some energy is always lost as heat, increasing the entropy of the surroundings.

A common way to express the second law is: 'The entropy of the universe tends to increase in spontaneous processes.'

Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Second Law of Thermodynamics

The second law of thermodynamics states that in any energy transfer or transformation, the total entropy of an isolated system can never decrease over time. This means that natural processes tend to move towards a state of greater disorder or randomness, indicating that energy transformations are not 100% efficient.

Entropy

Entropy is a measure of the disorder or randomness in a system. In thermodynamics, it quantifies the amount of energy in a physical system that is not available to do work. As entropy increases, the energy available for doing work decreases, which is a key aspect of the second law of thermodynamics.

Isolated System

An isolated system is one that does not exchange matter or energy with its surroundings. In the context of the second law of thermodynamics, it is important to consider isolated systems because the law applies to them, indicating that their entropy will always increase or remain constant, but never decrease.

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Textbook Question

Which state in each of the following pairs has the higher entropy per mole of substance? (d) Water vapor at 150 °C and 1 atm or water vapor at 100 °C and 2 atm

Textbook Question

What is the entropy change when the volume of 1.6 g of O2 increases from 2.5 L to 3.5 L at a constant temperature of 75 °C? Assume that O2 behaves as an ideal gas.

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Textbook Question

Make a rough, qualitative plot of the standard molar entropy versus temperature for methane from 0 K to 298 K. Incorporate the following data into your plot: mp = -182 °C; bp = -164 °C; °S = 186.2 J/(K*mol) at 25 °C.

Textbook Question

An isolated system is one that exchanges neither matter nor energy with the surroundings. What is the entropy criterion for spontaneous change in an isolated system? Give an example of a spontaneous process in an isolated system.

Textbook Question

Give an equation that relates the entropy change in the surroundings to the enthalpy change in the system. What is the sign of ∆Ssurr for the following?(a) An exothermic reaction(b) An endothermic reaction

Textbook Question

What are the values of x and y for the following reaction if E° = 0.91 V and ∆G° = -527 kJ?