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
Only when there is no product that is when a chemical reaction has not occured
The best description of the process to draw the segment is B. b place a compass at one endpoint of the segment and trace an arc. do the same from the other endpoint. draw a line through the intersections of the arcs.
<h3>What is a segment bisector?</h3>
It should be noted that a segment bisector simply means a line to segment which cuts another line segment at the center but dividing the lines into two equal halves.
In this case, based on the information given, the best description of the process to draw the segment is to place a compass at one endpoint of the segment and trace an arc, do the same from the other endpoint. draw a line through the intersections of the arcs.
In conclusion, the correct option is B.
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