The heat of combustion of carbon to CO2 is –393.5 KJ/mol. The heat released upon the formation of 35.2 g of CO2 from carbon and oxygen gas is:

1. –315 KJ 2. +315 KJ
3. –630 KJ 4. +630 KJ
Subtopic:  Thermochemistry |
 75%
Level 2: 60%+
NEET - 2015
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Calculate the heat released when 5 L of a gaseous mixture of methane (CH₄) and propane (C₃H₈) is completely combusted at 0°C and 1 atm, given that 16 L of oxygen is consumed.
Enthalpy of combustion: ΔHc(CH₄) = 890 kJ mol⁻¹, ΔHc(C₃H₈) = 2220 kJ mol⁻¹.
 
1. 38 2. 317
3. 477 4. 32
Subtopic:  Thermochemistry |
 64%
Level 2: 60%+
NEET - 2013
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The enthalpy of fusion of water is 1.435 kcal/mol. The molar entropy change for the melting of ice at 0 oC is:

1. 10.52 cal/(mol K) 2. 21.04 cal/(mol K)
3. 5.260 cal/(mol K) 4. 0.526 cal/(mol K)
Subtopic:  Thermochemistry |
 81%
Level 1: 80%+
AIPMT - 2012
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Give the following bond energies:
H—H bond energy: 431.37 kJ mol-1 
C=C bond energy: 606.10 kJ mol-1 
C—C bond energy: 336.49 kJ mol-1 
C—H bond energy: 410.50 kJ mol-1 

Enthalpy for the following reaction will be:

1. 1523.6 kJ mol-1
2. -243.6 kJ mol-1
3. -120.0 kJ mol-1
4. 553.0 kJ mol-1
Subtopic:  Thermochemistry |
 76%
Level 2: 60%+
AIPMT - 2009
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Bond dissociation enthalpy of H2, Cl2, and HCl are 434, 242, and 431 kJ mol1 respectively. Enthalpy of formation of HCl is:

1. 93 kJ mol-1
2. - 245 kJ mol-1
3. -93 kJ mol-1
4. 245 kJ mol-1

Subtopic:  Thermochemistry |
 66%
Level 2: 60%+
AIPMT - 2008
Hints

Consider the following reactions: 

(i) H+(aq) + OH-(aq) → H2O(l)
ΔH = -x1 kJmol-1
(ii) H2(g) + 1/2O2(g) → H2O(l)
ΔH = -x2 kJmol-1
(iii) CO2(g) + H2(g) → CO (g) + H2O(l)
ΔH = -x3 kJmol-1
(iv) C2H2(g) + 5/2O2(g) →  2CO+ H2O(l)
ΔH = -x4 kJmol-1


Enthalpy of formation of H2O(l) is :

1. -x3 kJ mol-1

2. -x4 kJ mol-1

3. -x1 kJ mol-1

4. -x2 kJ mol-1

Subtopic:  Thermochemistry |
 77%
Level 2: 60%+
AIPMT - 2007
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The bond energy of H—H and Cl-Cl is 430 kJ
mol-1 and 240 kJ mol-1 respectively and ΔHf for HCl is -90 kJ mol-1. The bond enthalpy of HCl is:

1. 290 kJ mol-1

2. 380 kJ mol-1

3. 425 kJ mol-1

4. 245 kJ mol-1

Subtopic:  Thermochemistry |
 63%
Level 2: 60%+
AIPMT - 2007
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The enthalpy of combustion of H2, cyclohexene (C6H10) and cyclohexane (C6H12) are -241, -3800 and -3920 kJ per mol respectively. Heat of hydrogenation of cyclohexene is:

1. -121 kJ per mol

2. +121 kJ per mol

3. +242 kJ per mol

4. -242 kJ per mol

Subtopic:  Thermochemistry |
 60%
Level 2: 60%+
AIPMT - 2006
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