Join the #1 community for gun owners of the Northwest
We believe the 2nd Amendment is best defended through grass-roots organization, education, and advocacy centered around individual gun owners. It is our mission to encourage, organize, and support these efforts throughout Oregon, Washington, Idaho, Montana, and Wyoming.
Discuss firearms and all aspects of firearm ownership
Join others in organizing against anti-gun legislation
Find nearby gun shops, ranges, training, and other resources
Discover free outdoor shooting areas
Stay up to date on firearm-related events
Share photos and video with other members
...and much more!
bond strength
In chemistry, bond energy (BE), also called the mean bond enthalpy or average bond enthalpy is the measure of bond strength in a chemical bond. IUPAC defines bond energy as the average value of the gas-phase bond-dissociation energy (usually at a temperature of 298.15 K) for all bonds of the same type within the same chemical species.The bond dissociation energy (enthalpy) is also referred to as
bond disruption energy, bond energy, bond strength, or binding
energy (abbreviation: BDE, BE, or D). It is defined as the standard
enthalpy change of the following fission: R - X → R + X. The BDE,
denoted by Dº(R - X), is usually derived by the thermochemical
equation,
D
∘
(
R
−
X
)
=
Δ
H
f
∘
(
R
)
+
Δ
H
f
∘
(
X
)
−
Δ
H
f
∘
(
R
X
)
{\displaystyle {\begin{array}{lcl}\mathrm {D^{\circ }(R-} X)\ =\Delta H_{f}^{\circ }\mathrm {(R)} +\Delta H_{f}^{\circ }(X)-\Delta H_{f}^{\circ }(\mathrm {R} X)\end{array}}}
The enthalpy of formation ΔHfº of a large number of atoms, free radicals, ions,
clusters and compounds is available from the websites of NIST,
NASA, CODATA, and IUPAC. Most authors prefer to use the
BDE values at 298.15 K.For example, the carbon–hydrogen bond energy in methane BE(C–H) is the enthalpy change (∆H) of breaking one molecule of methane into a carbon atom and four hydrogen radicals, divided by four. The exact value for a certain pair of bonded elements varies somewhat depending on the specific molecule, so tabulated bond energies are generally averages from a number of selected typical chemical species containing that type of bond.Bond energy (BE) is the average of all bond-dissociation energies of a single type of bond in a given molecule. The bond-dissociation energies of several different bonds of the same type can vary even within a single molecule. For example, a water molecule is composed of two O–H bonds bonded as H–O–H. The bond energy for H2O is the average of energy required to break each of the two O–H bonds in sequence:
H
−
O
−
H
→
H
⋅
+
⋅
O
−
H
,
D
1
⋅
O
−
H
→
⋅
O
⋅
+
⋅
H
,
D
2
H
−
O
−
H
→
H
⋅
+
⋅
O
⋅
+
⋅
H
,
D
=
(
D
1
+
D
2
)
/
2
{\displaystyle {\begin{array}{lcl}\mathrm {H-O-H} &\rightarrow &\mathrm {H\cdot +\cdot O-H} &,D_{1}\\\mathrm {\cdot O-H} &\rightarrow &\mathrm {\cdot O\cdot +\cdot H} &,D_{2}\\\mathrm {H-O-H} &\rightarrow &\mathrm {H\cdot +\cdot O\cdot +\cdot H} &,D=(D_{1}+D_{2})/2\\\end{array}}}
Although the two bonds are the equivalent in the original symmetric molecule, the bond-dissociation energy of an oxygen–hydrogen bond varies slightly depending on whether or not there is another hydrogen atom bonded to the oxygen atom.
When the bond is broken, the bonding electron pair will split equally to the products. This process is called homolytic bond cleavage (homolytic cleavage; homolysis) and results in the formation of radicals.
So I'm curious if anyone here has experience with both epoxy and acraglass. I have a small repair to make on a peice of wood "furniture" and I have some black industrial epoxy I could use but I'm wondering if I should hold off and wait for acraglass? I know both would probably work but I also...