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?

The bond dissociation energies of $X_2 , Y_2$ 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

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 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)

From 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 reaction, 

will be:

Consider the following reactions: 

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 $kJ$ $mo{l}^{-1}$

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