Answer:
b. Plants and animals exchanging gases with the atmosphere
Explanation:
Answer:
One nucleophilic center
Explanation;
Nucleophile:
Nucleophile is a substance which is nucleus loving in nature (<em>Nucleo</em>; Nucleus , <em>phile</em>; Loving). It is known as a specie which donates a lone pair of electrons to electrophile (electron loving) in a chemical reaction.
Thus, Nucleophile is the region of higher electron density in a molecule and attacks on the lower electron density region of another molecule. Also, the nucleophile can also contain a negative charge.
Number of Nucleophilic centers in Methanol:
The chemical structure of Methanol is attached below and it can be observed that the oxygen atom is containing two lone pair of electrons. Hence, the oxygen atom can act as a nucleophilic center. Therefore, there is only one nucleophilic center in methanol.
H₃C-OH + H₃C-Br → H₃C-O-CH₃ + HBr
In above reaction methanol is acting as a nucleophile and is attacking on electrophilic center (Carbon) of methyl bromide yielding dimethyl ether.
It is the nucleus of an atom
Hess law can help us to obtain the enthalpy of a series of reactions by summation. The missing enthalpy of this reaction is −198kJ.
<h3>
What is Hess law?</h3>
According to the Hess law of constant heat summation, the enthalpy of a sequence of reactions can be obtained as the sum of the enthalpies of all the reactions.
Now looking at all the reavtion written here in order to obtain the missing enthalpy, we conclude that the missing enthalpy is −198kJ.
Learn more about enthalpy: brainly.com/question/3393755
