An ideal gas in a thermally insulated vessel at internal pressure = \(P_1,\) volume = \(V_1,\) and absolute temperature = \(T_1\) expands irreversibly against zero external pressure, as shown in the diagram. The final internal pressure, volume, and absolute temperature of the gas are \(P_2\), \(V_2\) and \(T_2\), respectively. For this expansion, which of the following relation(s) hold true?

(a) \(q=0 \)
(b) \( T_2=T_1 \)
(c) \( P_2 V_2=P_1 V_1\)
(d) \(P_2 V_2^\gamma=P_1 V_1^\gamma \)
1. (a), (b), (c) 
2. (b), (d) 
3, (a), (d) 
4. None of the above
Subtopic:  Thermodynamics' Properties and process |
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Consider the two given statements:
Assertion (A): Heat and work are "definite quantities".
Reason (R): Heat and work are not properties of a system their values depend on the path of the process and vary accordingly.
 
1. Both (A) and (R) are True and (R) is the correct explanation of (A).
2. Both (A) and (R) are True but (R) is not the correct explanation of (A).
3. (A) is True but (R) is False.
4. (A) is False but (R) is True.
Subtopic:  Thermodynamics' Properties and process |
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At a pressure of \(5 \times 10^5\) bar, the densities of diamond and graphite are 3 g/cc and 2 g/cc, respectively, at a certain temperature T. Calculate the value of \(\Delta U-\Delta H \mathrm{}\) for the conversion of 1 mole of graphite to 1 mole of diamond at a temperature T.

1. \(100 \mathrm{~kJ} / \mathrm{mol}\)
2. \(50 \mathrm{~kJ} / \mathrm{mol}\)
3. \(-~100 \mathrm{~kJ} / \mathrm{mol}\)
4. \(-~50 \mathrm{~kJ} / \mathrm{mol}\)
Subtopic:  Enthalpy & Internal energy |
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Based on the reactions, ascertain the valid algebraic relationship:
(i) C(g) +4H (g) CH4(g); 
Hr =x kJ mol-1
(ii) C(graphite) + 2H2 (g)   CH4; 
Hr  = y kJ mol-1

1. x = y 2. x = 2y
3. x > y 4. x < y
Subtopic:  Enthalpy & Internal energy |
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Assertion (A): The heat absorbed during the isothermal expansion of an ideal gas against a vacuum is zero.
Reason (R): The volume occupied by the molecules of an ideal gas is zero.
 
1.  Both (A) and (R) are True and (R) is the correct explanation of (A).
2. Both (A) and (R) are True but (R) is not the correct explanation of (A).
3. (A) is True but (R) is False.
4. (A) is False but (R) is True.
Subtopic:  Enthalpy & Internal energy |
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An ideal gas is expanded irreversibly against 10 bar pressure from 20 litres to 30 litres. Calculate 'w' if the process is isoenthalpic.

1. 0 2. +100J
3. -100 J 4. -10 kJ
Subtopic:  First Law of Thermodynamics |
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A gas is allowed to expand in a well-insulated container against a constant external pressure of 2.5atm from an initial volume of 2.50 L to a final volume of 4.50L. The change in internal energy U of the gas in joules will be:

1. –500J 2. –505J
3. –506J 4. –508J
Subtopic:  First Law of Thermodynamics |
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Maximum work is obtained by the system in:
1. Irreversible  process  2. Reversible  process 
3. Adiabatic  process 4. Isobaric  process 
Subtopic:  First Law of Thermodynamics |
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Select the correct option based on statements below:
Statement I:  Total enthalpy change of a multistep process is the sum of  ∆H1 + ∆H2 + ∆H3 + . . .
Statement II: When heat is absorbed by the system, the sign of q is taken to be negative.
 
1. Statement I is correct; Statement II is correct.
2. Statement I is correct; Statement II is incorrect.
3. Statement I is incorrect; Statement II is correct.
4. Statement I is incorrect; Statement II is incorrect.
Subtopic:  First Law of Thermodynamics |
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Calculate the standard enthalpy of formation (\(\Delta_fH^\circ\)) for 2 moles of liquid benzene (\(\mathrm{{C_6H_6}_{(l)}}\)) at 25°C, based on the given thermodynamic data.
Given Data:
\(\Delta _c\mathrm H\mathrm{(C_6H_6}_\mathrm{(l)})~= -3264.6~ \mathrm{~kJ} / \mathrm{mol}\)
\(\Delta _c\mathrm H\mathrm{(C}_\mathrm{(s)})~= -393.5~ \mathrm{~kJ} / \mathrm{mol}\)
\(\Delta _f\mathrm H\mathrm{(H_2O}_\mathrm{(l)})~= -285.83~ \mathrm{~kJ} / \mathrm{mol}\)

1. \(-~92.22 \mathrm{~kJ} / \mathrm{mol}\)
2. \(-46.11 \mathrm{~kJ} / \mathrm{mol}\)
3. \(+~92.22 \mathrm{~kJ} / \mathrm{mol}\)
4. \(+46.11 \mathrm{~kJ} / \mathrm{mol}\)
Subtopic:  Thermochemistry |
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