Consider the following two isomeric alkenes. The first isomer is a mono substituted alkene, while the second isomer is a disubstituted alkene. We might expect the second isomer to be more stable, yet heats of combination for these two compounds indicate that the first isomer is more stable. Offer an explanation.

Explanation:

Since both the alkenes contain a 4 membered ring, both will contain ring strain.

We know that ring strain decreases the stability of the compound. Hence higher the ring strain, lower will be stability.

First alkene contains only sp3 carbons in the ring. Hence

ring starin = (109.50 - 900) =9.75 0 around each carbon

Similarly in the second alkene, ring contains two sp2 carbons and 2 sp3 carbons

Hence angle strain forsp2 carbons = (120 0 - 90 0) / 2 = 15 0

Therefore in the second alkene, due to higher angle strain around sp2 carbon atoms, the compound is less stable than the first alkene.

Hence first alkene is more stable than the the second one.

answer: - 3.) the oxidation state of nitrogen in no changes from +2 to 0, and the oxidation state of carbon in co changes from +2 to +4 as the reaction proceeds.

solution: - as per the rules, oxidation number of oxygen in its compounds is -2. the sum of oxidation numbers of all the elements of a molecule or compound is zero.

also, the oxidation number in elemental form is zero.

in no, the oxidation number of o is -2 so the oxidation number of n is +2 so that the sum is zero.

similarly, the oxidation number of c in co is +2 and o is -2.

on product side the oxidation number of n is 0 as it is in the elemental form() .

oxidation number of c in carbon dioxide is +4 as there are two oxygen in it and we know that each oxygen is -2.

so, oxidation number of n is changing from +2 to 0 and the oxidation number of c is changing from +2 to +4.

since nitrogen is reduced and hence no is acting as an oxidizing agent. carbon is oxidized and so co is acting as a reducing agent.

so, the right choice is number 3.)the oxidation state of nitrogen in no changes from +2 to 0, and the oxidation state of carbon in co changes from +2 to +4 as the reaction proceeds.

c-14 is carbon-14, or radiocarbon.   it is a radioactive isotope of carbon with an atomic nucleus containing 6 protons and 8 neutrons.