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\(1~\text g\) of water of volume \(1~\text{cm}^3\) at \(100^\circ \text{C}\) is converted into steam at the same temperature under normal atmospheric pressure \(\approx 1\times10^{5}~\text{Pa}.\) The volume of steam formed equals \(1671~\text{cm}^3.\) If the specific latent heat of vaporization of water is \(2256~\text{J/g},\) the change in internal energy is:

1. \(2423~\text J\) 2. \(2089~\text J\)
3. \(167~\text J\) 4. \(2256~\text J\)

Subtopic:  First Law of Thermodynamics |
 67%
Level 2: 60%+
NEET - 2019
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1 kg of gas does 20 kJ of work and receives 16 kJ of heat when it is expanded between two states. The second kind of expansion can be found between the same initial and final states, which requires a heat input of 9 kJ. The work done by the gas in the second expansion will be:

1. 32 kJ 2. 5 kJ
3. -4 kJ 4. 13 kJ
Subtopic:  First Law of Thermodynamics |
 79%
Level 2: 60%+
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For the isothermal reversible expansion of an ideal gas: 

1. H>0andU=0

2. H>0andU<0

3. H=0andU=0

4. H=0andU>0

Subtopic:  Enthalpy & Internal energy |
 57%
Level 3: 35%-60%
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An ideal heat engine (Carnot engine) works between temperatures \(T_1\) and \(T_2\) has an efficiency \(\eta.\) The new efficiency if both the source and sink temperatures are doubled will be:
1. \(\frac{\eta}{2}\)
2. \(\eta\)
3. \(2\eta\)
4. \(3\eta\)
Subtopic:  Carnot Engine |
 89%
Level 1: 80%+
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A monoatomic ideal gas, initially at temperature \(T_1\), is enclosed in a cylinder fitted with a frictionless piston. The gas is allowed to expand adiabatically to a temperature \(T_2\) by releasing the piston suddenly. If \(L_1\) and \(L_2\) are the lengths of the gas column before and after expansion, respectively, then \(\frac{T_1}{T_2}\) is given by:
1. \(\left(\frac{L_1}{L_2}\right)^{\frac{2}{3}}\)
2. \(\frac{L_1}{L_2}\)
3. \(\frac{L_2}{L_1}\)
4. \(\left(\frac{L_2}{L_1}\right)^{\frac{2}{3}}\)

Subtopic:  Types of Processes |
 71%
Level 2: 60%+
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The initial pressure and volume of a gas are \(P\) and \(V\), respectively. First, it is expanded isothermally to volume \(4V\) and then compressed adiabatically to volume \(V\). The final pressure of the gas will be: [Given: \(\gamma = 1.5\)]

1. \(P\) 2. \(2P\)
3. \(4P\) 4. \(8P\)
Subtopic:  Types of Processes |
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Level 2: 60%+
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The degree of freedom per molecule for a gas on average is 8. If the gas performs 100 J of work when it expands under constant pressure, then the amount of heat absorbed by the gas is:
1. 500 J
2. 600 J
3. 20 J
4. 400 J

Subtopic:  First Law of Thermodynamics |
 62%
Level 2: 60%+
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Calculate the Gibbs energy change when 1 mole of NaCl is dissolved in water at 298 K. Given,

a. Lattice energy of NaCl = 778 kJ mol-1

b. Hydration energy of NaCl =-774.3 kJ mol-1

c. Entropy change at 298 K = 43 JK-1 mol-1

1. -3.7 kJ 2. -9.1 kJ
3. -43 kJ 4. -13.14 kJ
Subtopic:  Thermochemistry |
 73%
Level 2: 60%+
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Work done during the given cycle is:
                               
1. 4P0V0

2. 2P0V0

3. 12P0V0

4. P0V0

Subtopic:  Work Done by a Gas |
 81%
Level 1: 80%+
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An ideal gas goes from \(A\) to \(B\) via two processes, \(\mathrm{I}\) and \(\mathrm{II},\) as shown. If \(\Delta U_1\) and \(\Delta U_2\) are the changes in internal energies in processes \(\mathrm{I}\) and \(\mathrm{II},\) respectively, (\(P:\) pressure, \(V:\) volume) then:

   

1. \(∆U_1 > ∆U_2\) 2. \(∆U_1 < ∆U_2\)
3. \(∆U_1 = ∆U_2\) 4. \(∆U_1 \leq ∆U_2\)
Subtopic:  Molar Specific Heat |
 89%
Level 1: 80%+
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