Which of the following statements is/are correct?
(a) Heat is a way of transferring energy.
(b) Heat is not a property of the system, whereas temperature is a property of the system.
(c) Reactions that are accompanied by the evolution of heat are called endothermic reactions.
(d) Those reactions in which heat is absorbed are known as exothermic reactions.

1. a and b
2. b, c and d
3. b and c
4. None of the above
Subtopic:  First Law of Thermodynamics | Classification of System, Extensive & Intensive Properties | Thermochemistry |
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Match the entries in Column-I with those given in Column-II:
Column-I Column-II
(A) Reversible process (p) \(\Delta G = -nFE\)
(B) Gibbs free energy (q) Infinite steps
(C) Standard enthalpy of reaction, \(\Delta_r H^{\ominus}\) (r) \(\sum\)bond enthalpies (reactants) – 
\(\sum\)bond enthalpies (products) 
(D) Enthalpy of bond formation, \(\Delta_f H_{\text {bond }}^{\ominus}\) (s) \(\sum \Delta_f H^{\ominus}\)(bonds of
products) 

\(\sum \Delta_f H^{\ominus}\)
(bonds
of reactants)
1. A-q, B-p, C-r, D-s
2. A-p, B-q, C-r, D-s
3. A-s, B-q, C-r, D-p
4. A-q, B-s, C-r, D-q
Subtopic:  Gibbs Energy Change | Thermochemistry |
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Give the following reaction: 
\(\mathrm{Ag}^{+}(\mathrm{aq})+\mathrm{Cl}^{-}(\mathrm{aq}) \rightarrow \mathrm{AgCl}(\mathrm{s}) \text { at } 25^{\circ} \mathrm{C} \text {. } \)

The value of \(\Delta_r H^{\circ}\) for the above reaction will be (given the following data):

\(\begin{aligned} & \Delta_{\mathrm{f}} \mathrm{{H}^{\circ}\left({Ag}^{+}, {aq}\right)=105 {~kJ} {~mol}^{-1}}, \\ & \Delta_{\mathrm{f}} \mathrm{{H}^{\circ}\left({Cl}^{-}, {aq}\right)=-167 {~kJ} {~mol}^{-1}} \text { and } \\ & \Delta_{\mathrm{f}} \mathrm{{H}^{\circ}({AgCl}, {s})=-127 {~kJ} {~mol}^{-1}} \end{aligned} \)
1. –65 kJ mol1 2. –75 kJ mol–1 
3. –50 kJ mol–1 4. –80 kJ mol–1
Subtopic:  Thermochemistry |
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Match Column I (Reactions) with Column II (Enthalpy) and mark the appropriate choice:
 
Column I (Reactions) Column II (Enthalpy)
(A) \(\small{CH_{4(g)} + 2O_{2(g)} \rightarrow CO_{2(g)} + 2H_2O}\) (i) \(\Delta _{sol}H^o\)
(B) \( H_{2(g)} \rightarrow 2H_{(g)}\) (ii) \(\Delta _{lattice}H^o\)
(C) \(NaCl_{(s)} \rightarrow Na^+_{(g)} + Cl^-_{(g)} \) (iii) \(\Delta _{c}H^o\)
(D) \(NaCl_{(s)} \rightarrow Na^+_{(aq)} + Cl^-_{(aq)} \) (iv) \(\Delta _{bond}H^o\)

1. (A) →(iv), (B)→(iii), (C) →(i), (D)→ (ii)
2. (A) →(ii), (B)→(i), (C) →(iv), (D)→ (iii)
3. (A) →(i), (B)→(ii), (C) →(iii), (D)→ (iv)
4. (A) →(iii), (B)→(iv), (C) →(ii), (D)→ (i)
Subtopic:  Thermochemistry |
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The enthalpy change for the reaction is called

         C2H4+3O22CO2+2H2O

1. Enthalpy of formation

2. Enthalpy of vaporisation

3. Enthalpy of sublimation

4. Enthalpy of combustion

Subtopic:  Thermochemistry |
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Consider a reaction: 
\(A_2 + B_2 \rightarrow 2AB\\ (g)~~~~(g)~~~~~~~~(g) \)

If \(\Delta H^o_f \) of \(A_2 , AB \) and \(B_2\) are in the ratio \(1: {1 \over 2}: 1\) and \(\Delta H \) of the reaction is -200 kJ/mol. The value of \(\Delta H^o_f~ (A_2)\)(kJ mol-1) is:

1. 250 
2. 200 
3. 300
4. 240
Subtopic:  Thermochemistry |
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Consider the following reaction:
\(\mathrm{2H_2(g) + O_2(g) \rightarrow 2H_2O(g); ~\Delta_rH^\circ = -483.64~ kJ }\)

What is the enthalpy change (in KJ) for the decomposition of one mole of water?
1. 120.9 2. 241.82
3. 18 4. 100
Subtopic:  Thermochemistry |
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NEET - 2023
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Given the following reaction:
\(\mathrm{C}_2 \mathrm{H}_4(g)+6 \mathrm{~F}_2(g) \rightarrow 2 \mathrm{CF}_4(g)+4 \mathrm{HF}(g)\)
Which species has a standard enthalpy of formation \((\Delta H^{\circ})\) equal to 0?
1. \(\mathrm{C}_2 \mathrm{H}_4\)
2. \(\mathrm{F}_2\)
3. \(\mathrm{CF}_4\)
4. \(\mathrm{HF}\)
Subtopic:  Thermochemistry |
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The heat of combustion of carbon (graphite) to CO2 is –393.5 kJ mol–1. The heat release upon formation of 15.84 g of CO2 from carbon
(graphite) and oxygen gas is-

1. 212.49 kJ
2. 141.66 kJ
3. 21.25 kJ
4. 42.5 kJ
Subtopic:  Thermochemistry |
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The enthalpy of vaporisation of a liquid is 30 kJ mol–1 and entropy of vaporisation is 75 J mol–1 k–1. What is the boiling point of the liquid at 1 atm?

1. 50 K 2. 400 K
3. 450 K 4. 600 K
Subtopic:  Thermochemistry |
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