Calculate the enthalpy for this reaction: 2c(s) + h2(g) > c2h2(g) δh° = kj given the following thermochemical equations: c2h2(g) + (5/2)o2(g) > 2co2(g) + h2o(ℓ) δh° = -1,123 kj c(s) + o2(g) > co2(g) δh° = -340 kj h2(g) + (1/2)o2(g) > h2o(ℓ) δh° = -211 kj

The enthalpy for given reaction is 232 kilo Joules.

Explanation:

...[1]

..[2]

..[3]

..[4]

2 × [2] + [3] - [1] ( Using Hess's law)

The enthalpy for given reaction is 232 kilo Joules.

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.

the mantle

explanation:

earth is divided into three layers: the crust or the outermost layer on which we live; the underlying, middle layer - the mantle - and the core (the innermost layer of earth).