Enthalpy of combustion of carbon to carbon dioxide is \(-390.0~\text{kJ mol}^{-1}.\) The amount of heat released when \(35.0~\text{g}\) of \(\mathrm{CO_2}\) is formed from the reaction of carbon and dioxygen gas, is:
1. \(310~\text{kJ}\) 2. \(490~\text{kJ}\)
3. \(245~\text{kJ}\) 4. \(700~\text{kJ}\)
Subtopic:  Enthalpy & Internal energy |
 75%
From NCERT
NEET - 2024
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For the following reaction at 300K 
\(\mathrm{A}_2(\mathrm{~g})+3 \mathrm{~B}_2(\mathrm{~g}) \rightarrow 2 \mathrm{AB}_3(\mathrm{~g})\)
the enthalpy change is +15 kJ, then the internal energy change is:

1. 19.98 K J 
2. 200 J
3. 1999 J 
4. 1.9988 kJ
Subtopic:  Enthalpy & Internal energy |
 76%
From NCERT
NEET - 2024
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What is the correct relationship between changes in enthalpy and internal energy within the following options?
1. \(\mathrm{\Delta {H}+\Delta {U}=\Delta {nR}} \)
2. \(\mathrm{\Delta {H}=\Delta {U -\Delta n_gRT}}\)
3. \(\mathrm{\Delta {H}=\Delta {U+\Delta n_gRT }}\)
4. \(\mathrm{\Delta {H} -\Delta {U=-\Delta n_gRT}}\)
Subtopic:  Enthalpy & Internal energy |
 83%
From NCERT
NEET - 2023
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For the reaction, 2Cl(g)  Cl2(g), the correct option is:

1. rH>0 and rS<0

2. rH<0 and rS>0

3. rH<0 and rS<0

4. rH>0 and rS>0

Subtopic:  Enthalpy & Internal energy | Spontaneity & Entropy |
 61%
From NCERT
NEET - 2020
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The standard enthalpy of vaporization vapHo for water at 100 oC is 40.66 kJ mol–1. The internal energy of vaporization of water at 100 oC (in kJ mol–1) is: 
(Assume water vapour behaves like an ideal gas.)

1. +37.56

2. –43.76

3. +43.76

4. +40.66

Subtopic:  Enthalpy & Internal energy |
 60%
From NCERT
AIPMT - 2012
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Given the following reaction:
\(4H(g)\)→  \(2 H_{2}\)\((g)\)
The enthalpy change for the reaction is -869.6 kJ. The dissociation energy of the H-H bond is:
1. -869.6 kJ
2. +434.8kJ
3. +217.4kJ
4. -434.8 kJ

Subtopic:  Enthalpy & Internal energy |
 68%
From NCERT
AIPMT - 2011
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Consider the following processes:

                                       ∆H (kJ/mol)
½ A → B                            + 150
3B → 2C + D                      –125
E + A → 2D                        +350

For B + D → E + 2C, ∆H will be-

1. 325 kJ/mol 

2. 525 kJ/mol

3. –175 kJ.mol 

4. –325 kJ/mol

Subtopic:  Enthalpy & Internal energy |
 75%
From NCERT
AIPMT - 2011
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The following two reactions are knownFe2O3(s)+3CO(g)2Fe(s)+3CO2(g);
H=-26.88 kJ
FeO(s)+CO(g)Fe(s)+CO2(g);
H=-16.5 kJ

The value of H for the following reaction

Fe2O3(s)+CO(g)2FeO(s)+CO2(g) is:

1. -43.3 kJ

2. -10.3 kJ

3. +6.2 kJ

4. +10.3 kJ

Subtopic:  Enthalpy & Internal energy |
 77%
From NCERT
AIPMT - 2010
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The difference between enthalpy (∆H) and internal energy (∆E) for the given below reaction,
under constant temperature, is:
\(C_{3} H_{8} \left(\right. g \left.\right) + 5 O_{2} \left(\right. g \left.\right) \rightarrow 3 CO_{2} \left(\right. g \left.\right) + 4 H_{2} O \left(\right. l \left.\right)\)

1. + RT 2. – 3RT
3. + 3RT 4. – RT
Subtopic:  Enthalpy & Internal energy |
 85%
From NCERT
AIPMT - 2003
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For the given reaction 

2H2O2(l)  2H2O(l) + O2(g), the heat of formations of H2O2(l)  and H2O (l) are -188 kJ/mol & -286 KJ/mol respectively. The change in the enthalpy of the reaction will be:

1.  – 196 kJ/mol

2.  + 196 kJ/mol

3.  + 948 kJ/mol

4.  – 948 kJ/mol

Subtopic:  Enthalpy & Internal energy |
 76%
From NCERT
AIPMT - 2001
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