Homolytic Bond Dissociation Energies - Revision history

Bes: /* B3LYP/6-311+G(2d,p) */

2021-04-07T15:45:14Z

B3LYP/6-311+G(2d,p)

2021-04-07T15:44:39Z

HF/6-31(G)d

2021-04-07T15:43:22Z

Example

2021-04-07T15:42:09Z

2021-04-07T15:40:46Z

2021-04-07T13:43:48Z

2021-04-07T13:38:43Z

2021-04-07T13:37:13Z

2021-04-07T13:35:46Z

2021-04-07T13:34:18Z

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 [[File:TB08_004.gif|400px]]
 Using a more accurate computational approach, B3LYP/6-311+G(2d,p):
 :- B3LYP Energy	-39.8561207613 Hartree
 :- B3LYP Energy	-79.8583705307 Hartree
 ::ΔH<sub>rxn</sub> = 0.14613 Hartree = 384 kJ/mol

@@ Line 7: / Line 7: @@
 can be determined using the calculated enthalpies of formation (ΔH<sub>f</sub>) using the following method:
 Using WebMO/Gaussian to calculate the ΔH<sub>f</sub>(H<sub>3</sub>C-CH<sub>3</sub>), returns the following:
 :[[File:Screen Shot 2021-04-07 at 8.13.05 AM.png|400px]]

@@ Line 1: / Line 1: @@
 Homolytic bond dissociation energies or just bond dissociation energies (BDE) is a measure of a particular bond strength. BDE are also referred to as bond enthalpies.
-For Δ<sub>example</sub>, the BDE for the C-C bond in
+==Example==
 :H<sub>3</sub>C-CH<sub>3</sub> --> H<sub>3</sub>C• + •CH<sub>3</sub>

@@ Line 1: / Line 1: @@
 Homolytic bond dissociation energies or just bond dissociation energies (BDE) is a measure of a particular bond strength. BDE are also referred to as bond enthalpies.
-For example, the BDE for the C-C bond in
+For Δ<sub>example</sub>, the BDE for the C-C bond in
 :H<sub>3</sub>C-CH<sub>3</sub> --> H<sub>3</sub>C• + •CH<sub>3</sub>

← Older revision		Revision as of 13:43, 7 April 2021
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	As can bee seen in this table (shown in all Gen Chem textbooks), the "average bond enthalpy" for a C-C bond is 348 kJ/mol.		As can bee seen in this table (shown in all Gen Chem textbooks), the "average bond enthalpy" for a C-C bond is 348 kJ/mol.
	[[File:TB08_004.gif\|400px]]		[[File:TB08_004.gif\|400px]]
		+
		+	Using a more accurate computational approach, B3LYP/6-311+G(2d,p):
		+	:- B3LYP Energy -39.8561207613 Hartree
		+	:- B3LYP Energy -79.8583705307 Hartree
		+	::ΔH<sub>rxn</sub> = 0.14613 Hartree = 384 kJ/mol

@@ Line 8: / Line 8: @@
 Using WebMO/Gaussian to calculate the ΔH<sub>f</sub>(H<sub>3</sub>C-CH<sub>3</sub>), returns the following:
 :[[File:Screen Shot 2021-04-07 at 8.13.05 AM.png|400px]]
-The energy, ie. ΔH<sub>f</sub>(H<sub>3</sub>C-CH<sub>3</sub>) is reported in units of Hartree, -79.2287548119 Hartree
+The RHF (Restricted HF) energy, ie. ΔH<sub>f</sub>(H<sub>3</sub>C-CH<sub>3</sub>) is reported in units of Hartree, -79.2287548119 Hartree
 Using WebMO/Gaussian to calculate the ΔH<sub>f</sub>(CH<sub>3</sub>•), returns the following:
 :[[File:Screen Shot 2021-04-07 at 8.13.05 AM.png|400px]]
-The energy, ie ΔH<sub>f</sub>(CH<sub>3</sub>•) is reported in units of Hartree, -39.5589916118 Hartree
+The RHF (Restricted HF) energy, ie ΔH<sub>f</sub>(CH<sub>3</sub>•) is reported in units of Hartree, -39.5589916118 Hartree
 :ΔH<sub>rxn</sub> = ΔH<sub>f</sub>(Products) - ΔH<sub>f</sub>(Reactants)

← Older revision		Revision as of 13:35, 7 April 2021
Line 1:		Line 1:
−	Homolytic bond dissociation energies or just bond dissociation energies (BDE) is a measure of a particular bond strength. For example, the BDE for the C-C bond in H<sub>3</sub>C-CH<sub>3</sub> --> H<sub>3</sub>C• + •CH<sub>3</sub> can be calculated using the calculated enthalpies of formation (ΔH<sub>f</sub>) using the following method:	+	Homolytic bond dissociation energies or just bond dissociation energies (BDE) is a measure of a particular bond strength.
		+
		+	For example, the BDE for the C-C bond in
		+	:H<sub>3</sub>C-CH<sub>3</sub> --> H<sub>3</sub>C• + •CH<sub>3</sub>
		+
		+	can be calculated using the calculated enthalpies of formation (ΔH<sub>f</sub>) using the following method:

	Using WebMO/Gaussian to calculate the ΔH<sub>f</sub>(H<sub>3</sub>C-CH<sub>3</sub>), returns the following:		Using WebMO/Gaussian to calculate the ΔH<sub>f</sub>(H<sub>3</sub>C-CH<sub>3</sub>), returns the following:

← Older revision		Revision as of 13:34, 7 April 2021
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	:ΔH<sub>rxn</sub> = 2*-39.5589916118 - (-79.2287548119)		:ΔH<sub>rxn</sub> = 2*-39.5589916118 - (-79.2287548119)
	:ΔH<sub>rxn</sub> = 0.110771588 Hartree = 290.830826448 kJ/mol		:ΔH<sub>rxn</sub> = 0.110771588 Hartree = 290.830826448 kJ/mol
		+	::According to Engel, 2nd, Chapter 15, table 15.2, the actual value is 406 kJ/mol)
		+
		+	As can bee seen in this table (shown in all Gen Chem textbooks), the "average bond enthalpy" for a C-C bond is 348 kJ/mol.
		+	[[File:TB08_004.gif\|400px]]