Bond energy and heat of formation

Question

Discussion:

Bond energy and heat of formation

1. 0.412 mol of a solid was dissolved in 200 mL of water at 21.2 oC. After the solid had fully dissolved, the final temperature of the solution was 17.9 oC. What is the molar heat of solution of the substance?
_______________kJ/mol

2. Use Appendix B and the fact that the heats of formation of OF₂ and OCl₂ are 24.7 and 80.37 kJ/mol, respectively to determine the

O-F and O-Cl bond energies.
DO-F = kJ/mol
DO-Cl = kJ/mol

3. Use Appendix B to determine the atomization energy of PCl₃ and the average P-Cl bond energy in PCl₃.

DP-Cl = kJ/mol

Use the P-Cl bond energy and the atomization energy of POCl₃ to determine the P-O bond energy in POCl₃.

DP-O = kJ/mol

4. Use Bond energies (Table 3.3) to estimate the heats of formation of the following gases:

Compound Hf (kJ/mol)
NF₃ =
H2N-NH₂ =
F2C=CH₂* =
CH₃Cl* =

Hint: The standard state of carbon is solid graphite, but bond energies are for reactions in which all reactants and products are in the gas phase. You must use the heat of formation of carbon gas and bond energies to determine this energy.

5. C₁₈H₁₂(s)+ O₂(g) CO₂(g) + H₂O(l)
ng = mol
What is Hcomb of chrysene if Ecomb = -8942.6 kJ/mol?
Hcomb = kJ/mol
What is the heat of formation of chrysene? Appendix B
Hf = kJ/mol

6. The combustion of 2.350 mmol of X caused the temperature of a bomb calorimter to rise from 23.900 oC to 26.100 oC. Assume T = 25.000 oC, Hcomb = -2896 kJ/mol, and ng = -2 mol gas/mol X for the combustion and determine the heat capacity of the calorimeter.
C = kJ/oC

7. The heat of combustion of liquid toluene (C₇H₈) is -3910.3 kJ/mol at 1 atm and 298 K.

a) What is the energy of combustion at 1 atm and 298 K?
Ecomb = ____________kJ/mol

Attachment:- Tables.rar