Second Law of Thermodynamics

Q. why is entropy maximum at equilibrium?

Q.

What are the limitations of Second Law of Thermodynamics?

Q.

Why entropy is a state function?

Q.

What are the applications of thermodynamics?

Q.

For a chemical reaction $\mathrm{A}+\mathrm{B}\rightleftharpoons \mathrm{C}+\mathrm{D}$ ($∆{\mathrm{rH}}^{\mathrm{\psi }}=80\mathrm{kJ}{\mathrm{mol}}^{-1}$) the entropy change $∆{\mathrm{rS}}^{\mathrm{\psi }}$depends on the temperature $\mathrm{T}$(in $\mathrm{K}$) as $∆\mathrm{rS}=2\mathrm{T}(\mathrm{J}{\mathrm{K}}^{-1}{\mathrm{mol}}^{-1})$. Minimum temperature at which it will become spontaneous is $\mathrm{K}$,

Q.

What does it mean when entropy is zero?

Q. For a reaction taking place in a container in equilibrium with its surroundings, the effect of temperature on its equilibrium constant K in terms of change in entropy is described by:

1. With increase in temperature, the value of K for exothermic reaction decreases because entropy change of the system is positive
2. With increase in temperature, the value of K for endothermic reaction increases because unfavourable change in entropy of the surroundings decreases
3. With increase in temperature, the value of K for endothermic reaction increases because the entropy change of the system is negative
4. With increase in temperature, the value of K for exothermic reaction decreases because favourable change in entropy of the surrounding decreases

Q. Match the thermodynamic processes given under Column I with the expressions given under Column II.

$\begin{array}{cc}\text{Column I}& \text{Column II}\\ \text{(A) Freezing of water at 273 K and 1 atm}& \text{(P)}q=0\\ \text{(B) Expansion of 1 mol of an ideal gas into a}& \text{(Q)}w=0\\ \text{vacuum under isolated conditions}& \\ \text{(C) Mixing of equal volumes of two ideal gases at}& \text{(R)}\Delta S_{sys}<0\\ \text{constant temperature and pressure in an}& \\ \text{isolated container}& \\ \text{(D) Reversible heating of}{H}_2\left(g\right)\text{at 1 atm from}& \text{(S)}\Delta U=0\\ \text{300 K to 600 K, followed by reversible cooling}& \\ \text{to 300 K at 1 atm}& \\ & \text{(T)}\Delta G=0\end{array}$

1. $(A-R,T)(B-P,Q,S)(C-P,Q,S)(D-P,Q,S,T)$
2. $(A-R,T)(B-P,S)(C-P,S)(D-P,Q,R,S,T)$
3. $(A-R)(B-P,Q,S)(C-S)(D-P,Q,R,S,T)$
4. $(A-P,Q,S)(B-Q)(C-P,Q,S)(D-P,Q,S,T)$

Q. The incorrect expression among the following is:

1. For isothermal process $w_{reversible}=-nRTln\frac{V_f}{V_i}$
2. $\frac{\Delta G_{system}}{\Delta S_{Total}}=-T_{\left(atconstantP\right)}$
3. $lnK=\frac{\Delta H^o-T\Delta S^o}{RT}$
4. $K=e^{-\Delta G^o/RT}$

Q. State second law of thermodynamics.

Q.

The number of molecules in a volume of $4c{m}^3$a perfect monatomic gas at some temperature$T$ and pressure of$2cm$ of mercury is close to? (Given, that the mean kinetic energy of a molecule (at $T$)is$4\times {10}^{-14}erg$, $g=980cm{s}^{-2}$the density of mercury = $13.6gc{m}^{-3}$)

1. $4·0\times {10}^{18}$

2. $4·0\times {10}^6$

3. $5·8\times {10}^{16}$

4. $5·8\times {10}^{18}$

Q.

Why is entropy generation always positive?

Q. The total entropy change for a system and its surroundings increases, if the process is:

1. Reversible
2. Irreversible
3. Exothermic
4. Endothermic

Q. A container has hydrogen and oxygen mixture in ratio of 4:1 by weight, then
A. U of system increases
B. U of system decreases
C. S of mixture increases
D. S of mixture decrease
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What should be the answer of this question according to you and why?

Q. 10. At room temperature (293K) orange juice gets spoilt in about 64hr. In a refrigerator at 276K juice can be stored three times as long before it gets spoilt. How long should it take for the juice to get spoiled at 313K.

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Is time a function of entropy?

Q. State the various statements of Second law of Thermodynamics.

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What is thermal efficiency formula?

Q. Considering entropy (S) as a thermodynamic parameter, the criterion for the spontaneity of any process is

1. ${\Delta }_{sys}S+{\Delta }_{surr}S$ $>$ $0$
2. ${\Delta }_{sys}S-{\Delta }_{surr}S$ $>$ $0$
3. ${\Delta }_{sys}S$ $>$ $0$ only
4. ${\Delta }_{surr}S$ $>$ $0$ only

Q. During winters, moisture condenses in the form of dew and can be seen on plant leaves and grass. The entropy of the system in such cases decreases as liquids possess a lower disorder as compared to gases. With reference to the second law, which statement is correct, for the above process?

1. The randomness of the universe decreases
2. The randomness of the surrounding decreases
3. Increase in randomness of surroundings equals the decreases in randomness of system
4. The increase in randomness of the surrounding is greater as compared to the decrease in randomness of the system.

Q. Second law of thermodynamics defines :

1. heat
2. work
3. enthalpy
4. entropy

Q.

Which law of thermodynamics defines entropy?

Q.

What is the emissivity of a black body?

Q.

How do you increase thermal efficiency?

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Is entropy a law?

Q. Identify the endergonic reaction from the following reactions?

1. The synthesis of sugar in photosynthesis
2. The break down of sugar in cellular respiration
3. The break down of fats to release energy
4. break down of sugar in photosynthesis
5. break down of ATP

Q. The total amount of energy in the universe is fixed, but

1. Gravitation is decreasing
2. Matter is increasing
3. Disorder is increasing
4. Lightning is increasing

Q. Can heat and work become equal under any condition during a chemical reaction ?

Q. An endothermic reaction is one in which:

1. heat is converted into electricity
2. heat is absorbed
3. heat changes to mechanical work
4. heat is evolved

Q. If a heat engine does 100 kJ of work per cycle while releasing 400 kJ of heat, what is its efficiency?

1. 20%
2. 25%
3. 80%
4. 400%