Consider the halogenation of ethene is as follows:
CH₂=CH₂(g) + X₂(g) → H₂CX-CH₂X(g)
We can expect that this reaction occurring by breaking of a C=C bond and forming of two C-X bonds.
When bond break it is endothermic and when bond is formed it is exothermic.
So we can calculate the overall enthalpy change as a sum of the required bonds in the products:
Part a)
C=C break = +611 kJ
2 C-F formed = (2 * - 552) = -1104 kJ
Δ H = + 611 - 1104 = - 493 kJ
2C-Cl formed = (2 * -339) = - 678 kJ
ΔH = + 611 - 678 = -67 kJ
2 C-Br formed = (2 * -280) = -560 kJ
ΔH = + 611 - 560 = + 51 kJ
2 C-I Formed = (2 * -209) = -418 kJ
ΔH = + 611 - 418 = + 193 kJ
Part b)
As we can see that the highest exothermic bond formed is C-F bond so from bond energies we can found that addition of fluoride is the most exothermic reaction
<span>will metal do is when they ionize they have relatively high energies.These atoms have large diameters. The outer electrons are relatively far from the nucleus. Metals tend to lose electrons and form positive ions.</span>
In this lab activity, a solution of gum arabic was added to a solution of gelatin to form coacervates<span>. Gum arabic is made up of </span>carbohydrate macromolecules<span> while gelatin is made up of </span>protein macromolecules<span>. this lab show how the earth was formed from many different molecules.</span>
