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The thermodynamic relation expressing the change at temperature with volume at constant entropy is
Select one:
From thermodynamic Maxwell equation :
The correct answer is:
A sample of an ideal gas with initial pressure p and volume V is taken through an isothermal expansion proceed during which the change in entropy is found to be ΔS. The universal gas constant is R. Then, the work done by the gas is given by
Select one:
By ideal gas equal,
pV = nRT
Multiplying both the equations,
pVΔS = nRΔQ
∴ For isothermal expansion, ΔT = 0
The correct answer is: pVΔS\nR
The Gibb’s potential is defined as :
Select one:
Gibb’s free energy, denoted by G, combines enthalpy and entropy into a single value
The free energy is defined as follows
G = H – TS
Since H = U + pV
G = U + pV – TS
The correct answer is:
G = U + pV – TS
The thermodynamical relation expressing TdS equation.
Select one:
Let the entropy S of a thermodynamic system be a function of temperature T and Volume V i.e.
S = f(T, V)
Since dS is perfect differential, we can write
Multiplying by T, we get
For any substance, the specific heat at constant volume is given by
Using dQ = TdS
Also, from Maxwell’s equation, we have
The correct answer is:
The thermodynamical potential enthalpy H = U + pV, then which of the following relation hold true?
Select one:
H = U + pV
dH = dU + pdV + Vdp
dH = dQ + Vdp
⇒ dH = TdS + Vdp
Take S to be constant
take p to be constant
The correct answer is:
The combined form of first and second law of thermodynamics is given by (p = pressure, V = volume, T = temperature, U = internal energy, S = entropy, Q = quantity of heat)
Select one:
According to first law of thermodynamics
dQ = dU + pdV ...(1)
According to second law of thermodynamics
Combined form of (1) and (2)
TdS = dU + pdV
The correct answer is: TdS = dU + pdV
Helmholtz free energy in given as F = U – Ts then which of the relations hold true?
Select one:
F = U – TS
dF = dU – TdS + SdT
take V to be constant
The correct answer is:
The Gibb’s function G in thermodynamics is defined as
G = H – TS
In an isothermal, isobaric, reversible process, G
(where H = Enthalpy, T = Temperature, S = Entropy)
Select one:
Condition for a change to occur in any process
dU – TdS ≤ –pdV
d(U – TS + pV) ≤ 0
⇒ d(H – TS) ≤ 0
Since, G = H – TS
We get dG ≤ 0
it means in isothermal, isobaric and reversible process,
dG = 0 or G = constant
The correct answer is: Remains constant but not zero
Gibb’s thermodynamical potential can be represented as G = H – TS. Which relation hold true?
[Where H = Enthalpy, S = Entropy]
Select one:
We know that
dU = TdS – pdV + µdN
take U to be constant and N to be constant
we get
The correct answer is:
The enthalpy of unit mass for any system is
Select one:
The enthalpy of a homogeneous system is defined as
H = U + pV
The U term can be interpreted as the energy required to create the system, and the pV terms as the energy that would be required to “make room” for the system if pressure of the environment remained constant.
The correct answer is:
H = U + pV
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