Answer:
using bond energies = - 37 kJ
using enthalpies of formation = - 45.7 kJ
Explanation:
From the reaction;
CH2═CH2(g) + H2O(g) -------> CH3CH2OH(g)
From the above reaction; there are 4 (C-H) bonds , 1 ( C=C) and 2 (H-O) of ethene which forms 5(C-H) bonds, 1 (C-C) and 1 (C-O) and 1(H-O) bonds.
Using Bond Energies; the heat of the reaction can be written as:
∑ energy of old bond breaking + ∑ energies of the new bond formation.
∑ + ∑
∑+ ∑
-37 kJ
To calculate the heats of reaction by using enthalpies of formation; we have:
∑ - ∑
∑ - ∑
(-235.1 kJ) - [(+52.47 kJ) + (-241.826 kJ)]
-45.7 kJ
Chemical changes are considered unseen because they occur at the atomic level, changing the actual structure of the thing.
The reaction for magnesium iodide when put into water is as below
MgI2(s) → Mg^2+(aq) + 2I^-(aq)
when magnesium iodide but into water it dissociate/ ionize completely into Mg^2+ and 2l^- ions. Magnesium iodide dissociate/ionize completely because magnesium iodide is a strong electrolyte which dissociate/ ionize completely into their ions when it is put into water .
Answer:
Compound B and D
Explanation:
Both are good conductors of electricity.