Hello everyone today we will discuss thermodynamics MCQ with proper hints. we have to take about details of thermodynamics questions and answer for entrance examinations like CSIR NET GATE IIT JAM and equivalent entrance examinations. First of all, we are talking about chemical science-related discussion due to this website or portal is provide the best quality questions with a proper solution that is helpful for entrance exam aspirants.
We have to discuss the top five thermodynamics questions and answer for CSIR aspirant and equivalent entrance examinations. We are trying to our best knowledgeable question and answer for you, hope that that is helpful for you. If you have any queries regarding this question-answer series you can ask in the comment section below or you can ask our official Facebook page @chemclip otherwise Twitter handles @chem_clip.
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| This is the Thermodynamics Questions and Answer series for CSIR NET, GATE IIT JAM, and other entrance examination aspirants. |
This is the first lecture in the thermodynamics chapter. we have to briefly discuss on MCQ question series and relative hints to provide.
Thermodynamics Questions with the solution:
The Very important chapter of chemical science is thermodynamics-1, it is easy to learn and easy to approach, and understandable. The top five previous year questions in Thermodynamics chapters with solutions are given below. Or you can try to solve these questions and figure out the result of your scoring purpose. If you are interested then you can try it.
Q.1. When crystals of sodium chloride are heated in the presence of sodium vapor, they turn yellow. This is due to the formation of
- Schottky defects
- Frenkel defects
- F-centres
- H-centres
Option: 3. F-centres
Q.2. At pH 7.2 and 10 Torr oxygen partial pressure, the extent of O2 binding is
- High for both hemoglobin and myoglobin
- High for myoglobin and low for hemoglobin
- Low for both hemoglobin and myoglobin
- High for hemoglobin and low for myoglobin
Option 2: High for myoglobin and low for hemoglobin
Q.3. Of the following inequalities, the criterion/criteria for spontaneity of a chemical reaction is/are
(i) (∆G)T,P > 0 (ii) (∆U)S,V >0 (iii) (∆S)U,V > 0
- (i) only
- (ii) only
- (i) and (ii)
- (i) and (iii)
Option 4: (i) and (iii)
Hints: For the spontaneity of a chemical reaction follow those steps (∆G)T,P > 0 and (∆S)U,V > 0
Q.4. One mole of an ideal gas is compressed from 5 L to 2 L at a constant temperature. The change in entropy, in J K-1, of the gas is __. (R = 8.314 J K-1 mol-1)
Answer: -7.61
Hints:
At constant temperature, or at Isothermal process internal energy of this system ΔU = 0,
According to thermodynamics first low we get, ΔU = Q + W or 0 = Q + W or W = – Q.
ΔS=Q/T or ΔS=-W/T where Work done W= -nRTln(V_2/V_1)
Then ΔS= nRln (V_2/V_1) and put the value of the initial volume of gas V_1= 5L and the Final volume of gas V_2= 2L. We get
ΔS= 1 mol ×8.314×ln 2/5
ΔS=-7.61 J/K
Hence, The change in entropy, in J K-1, of the gas is 7.61.
Q.5. For an elementary bimolecular gas-phase reaction, activation energy is 5.5 kJ mol-1. Enthalpy of activation, in kJ mol-1, at 300 K is _. (R = 8.314 J K-1 mol-1)
Answer: 0.512 KJ
Hints:
We know, For an elementary bimolecular gas-phase reaction, Activation energy (Ea) and Enthalpy activation (ΔH#) relation is
Ea = (ΔH)^#+2RT and put the value of activation energy Ea = 5.5×1000 at temperature 300K. We get…
5.5×1000 = (ΔH)^#+2×8.314×300
(ΔH)^# = 5500-4988 = 512 J.(mol)^(-1)= 0.512 KJ.(mol)^(-1)
Enthalpy of activation is 0.512 KJ.
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