Let us consider entropy at the initial state 1 is S1 and entropy at the final state 2 is S2.
Hence, the change in entropy of a system, as it undergoes a change from state 1 to 2, becomes
S2 - S1 = 2∫1 (δQ / T) ...

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In order to prove that entropy is a property, we will suppose two cycles i.e. 1-A-2-B-1 and 1-A-2-C-1 as shown in
For a reversible cycle 1-A-2-B-1:
∫1-A-2 δQ / T + ∫2-B-1 δQ / T = 0
For a reversible cycle 1-A-2-C-1:
∫1-A-2 δQ / T + ∫2-C-1 ...

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The various relationships between internal energy (U), enthalpy (H), Helmholtz free energy (a) and Gibbs free energy (g), with relevant parameters such as entropy, pressure, temperature and volume are given by the following equations:
1. dU = TdS – PdV
2. dH = TdS + VdP
3. dA = - SdT ...

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Entropy Principle:
Form the Clausius inequality, ∫ δQ / T ≤ 0
As the entropy is a property of the system, therefore the cyclic integral of a property is zero and the above equation can also be written as:
∫ δQ / T ≤ ∫ dS
SQ / T ...

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Entropy is a measure of the degree of randomness of the molecules comprising the system. Higher the disorder, greater is the increase in entropy. Entropy is the function of a quantity of heat which shows the possibility of conversion of that heat into work. The ...

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The second law of thermodynamics can also be stated using Clausius, Kelvin and Planck statements also. Each statement is based on an irreversible process.
The Clausius and the Kelvin and Planck statements of the second law of Thermodynamics are given below:
Clausius statement:
Clausius statement states “it is ...

Maximum efficiency of an engine working between temperatures T2 and T1 is given by the fraction of the heat absorbed by an engine which can be converted into work is known as efficiency of the heat engine.
Mathematically,
In First case:
Efficiency, η = (T2 - T1) ...

Change in entropy during constant volume process is given as:
= m cv ln (T2 / T1)
Change in entropy during polytropic process i.e. (PVn = constant)
= m cv [(γ – n)/ (n – 1)] ln (T2 / T1)
For the same entropy, equating both the above equations, ...

ContinueComments Off on An ideal gas is heated from temperature T_{1} to temperature T_{2} by keeping its volume constant. The gas is expanded back to its initial temperature according to the law PV^{n} = constant. If the entropy changes in the two processes are equal, find the value of n in terms of the adiabatic index γ