Determine bond energy using heat of formation?
Use the following data to determine the C-C bond energy in cyclopropane. Heat of formation of cyclopropane (C3H6) : +32.2kJ Heat of atomization of carbon L +717kJ H-H Bond energy = 436kJ C-H Bond Energy = 410 I've normally encountered sums where I have to find the heat of change of formation using bond energies but this includes heat of atomisation and I'm not sure where to plug it in the equation?
Finding the average bond energy from heat of formation values?
105/2 kJ/mole 284/4 kJ/mole and 402/6 kJ/mole respectivley Oops we need to account for breaking a F2 bond.... Xe + x F2 ---> XeF2x Heat of forrmation per Xe-F is Xe-F bond - 1/2 F-F bond 158 KJ/mole is F-F bond strength is my guess??
Determining Bond Energy Using Heats of formation?
1/2 O2 + F2 = OF2 (formation of OF2) DeltaH = bonds broken - bonds formed = 2 D(OF) - D(FF) - 1/2 D(OO) Plug in the Delta H value for the heat of formation given, and look up the FF and OO bond energies in your textbook. Solve for D(OF) The same process for D(OCl) except you use the other heat of formation and look up D(Cl-Cl) instead.
Use bond energies and the fact that the heats of formation of OF2 and OCl2 are 24.7 and 80.37 kJ/mol, respecti?
½O2 + F2 → OF2 ΔHf = +24.7 kJ mol^-1 I am assuming this is an endothermic cmpd Break down into three steps ½O2→ O ½ΔHdiss(O2) = +494/2 = +247 kJ mol^-1 [1] F2→ 2F ΔHdiss(F2) = +155 kJ mol^-1 [1] O +2F →OF2 -2ΔHdiss(O-F) From Hess’ Law ΔHf = ½ΔHdiss(O2) + ΔHdiss(F2) -2ΔHdiss(O-F) 24.7 = +247 + 155 - 2ΔHdiss(O-F) ΔHdiss(O-F) = (247 + 155 – 24.7)/2 = 188 kJ mol^-1 Lit[1] 190 kJ mol^-1 (close enough!) You should be able to do OCl2 [1] http://www.wiredchemist.com/chemistry/da...
HELP finding heat of formation from bond energies.. Very confused.. please help!! thank you?
Use Bond Energies in Table 3.3 of the print book or the Bond Energy Resource in the on-line textbook to estimate the heats of formation of the following gases: (i included the bond energies in the bottom) a) NF3 b) H2N-NH2 c) F2C=CH2* d) CH3Cl* *Hint: Heats of formation have all reactants and products in their standard state. The standard state of carbon is solid graphite, whereas bond energies used in calculations are gas-phase energies. You can use the heat of formation of carbon gas to estimate the C-C bond energy in graphite. Bond energies in kJ/mol: N-F: 272 N-N: 163 N-H: 391 C=C: 612 C-H: 413 C-F: 485 H-Cl: 431 C-Cl: 328
Determining Delta Hf using bond energies...NEED HELP BY TONIGHT!!!?
Use Bond Energies in Table 3.3 of the print book or the Bond Energy Resource in the on-line textbook to estimate the heats of formation of the following gases: Compound Hf (kJ/mol) NF3 = H2N-NH2 = F2C=CH2* = CH3Cl* = *Hint: Heats of formation have all reactants and products in their standard state. The standard state of carbon is solid graphite, whereas bond energies used in calculations are gas-phase energies. You can use the heat of formation of carbon gas to estimate the C-C bond energy in graphite. C-H 413 N-H 391 O-H 463 H-H 436 C-F 485 N-F 272 O-F 190 H-F 565 F-F 159 C-Cl 328 N-Cl 200 O-Cl 203 H-Cl 431 Cl-Cl 243 C-Br 276 N-Br 243 O-Br 235 H-Br 366 Br-Br 193 C-I 234 O-I 234 H-I 299 I-I 151 --------------------------------------... C-C 347 N-N 163 N-O 201 C-N 293 C-O 358 O-O 146 C=C 612 N=N 418 N=O 607 C=N 615 C=O 799 O=O 495 CC 820 NN 941 CN 891 CO 1072
Heats of formation from bond energies! help please! thank you?
Use Bond Energies in Table 3.3 of the print book or the Bond Energy Resource in the on-line textbook to estimate the heats of formation of the following gases: a) NF3 b) H2N-NH2 c) F2C=CH2* d) CH3Cl* *Hint: Heats of formation have all reactants and products in their standard state. The standard state of carbon is solid graphite, whereas bond energies used in calculations are gas-phase energies. You can use the heat of formation of carbon gas to estimate the C-C bond energy in graphite. Bond energies in kJ/mol: C-H 413 N-H 391 O-H 463 H-H436 C-F 485 N-F 272 O-F 190 H-F 565 F-F 159 C-Cl 328 N-Cl 200 O-Cl 203 H-Cl 431 Cl-Cl 243 C-Br 276 N-Br 243 O-Br 235 H-Br 366 Br-Br193 C-I 234 O-I 234 H-I 299 I-I 151 C-C 347 N-N 163 N-O 201 C-N293 C-O 358 O-O 146 C=C 612 N=N 418 N=O 607 C=N 615 C=O799 O=O 495 Ctriple bond 820 Ntriple bond 941 Ctriple bond 891 Ctriple bond 1072
Us the bond energies in the table to determine delta H for the formation of hydrazine, N2H4,?
∆H°f = ∑∆H(bonds broken) -∑∆H(bonds formed) ∆H°f = [(N≡N) + 2 * (H-H)] - [4 * (N-H) + (N-N)] ∆H°f = [(941) + 2 * (436)] - [4 * (389) + (159)] ∆H°f = +98 kJ/mol. The structure is H2NNH2, all bonds are single covalent bonds, though I'm sure you figured that from the 2nd half of the calculations above. Both nitrogens have a lone electron pair.