Thermochemistry

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

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) → 2CO2 + H2O(l) ΔH = -x4 kJmol-1

Enthalpy of formation of H₂O(l) is :

1. $-x_3$ $kJ$ $mo{l}^{-1}$

2. $-x_4$ $kJ$ $mo{l}^{-1}$

3. $-x_1$ $kJ$ $mo{l}^{-1}$

4. $-x_2$ $kJ$ $mo{l}^{-1}$

The bond energy of H—H and Cl-Cl is 430 kJ
mol^-1 and 240 kJ mol^-1 respectively and ΔH_f for HCl is -90 kJ mol^-1. The bond enthalpy of HCl is:

1. 290 $kJ$ $mo{l}^{-1}$

2. 380 $kJ$ $mo{l}^{-1}$

3. 425 $kJ$ $mo{l}^{-1}$

4. 245 $kJ$ $mo{l}^{-1}$

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

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)

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

The bond dissociation energies of X₂ , Y₂ and XY are in the ratio of 1 : 0.5 : 1. ∆H for the formation of XY is –200 kJ mol^–1. The bond dissociation energy of X₂ will be

At standard conditions, if the change in the enthalpy for the following reaction is –109 kJ mol^–1
H_2(g)+Br_2(g)$\to$2HBr_(g) and the bond energy of H₂ and Br₂ is 435 kJ mol^–1 and 192 kJ mol^–1 respectively, what is the bond energy (in kJ mol^–1) of HBr?

1.	368	2.	736
3.	518	4.	259

The standard heat of formation, in kcal/mol of is :
[Given : standard heat of formation of ion (aq) , standard heat of crystallisation of standard heat of formation of

1.		2.
3.		4.