Use the bond energies provided to estimate ΔH°ᵣₓₙ for the reaction below.

Chemistry

1 answer:

Orlov [11]4 years ago

7 0

Answer:

The answer is b), -228 kJ

Explanation:

First, we consider which bonds are broken and formed during the reaction

Broken, Br - Br (02 molecules), C ≡ C

Formed, C - C, C - Br (4 bonds)

Noted that when breaking bonds, the molecules NEED energy, while forming bond, they release energy. So, secondly, we calculate

Breaking energy = 2 x (Br-Br) + 1 x (C≡C) = 2 x 193 + 1 x 837 = 1,223 kJ

Forming energy = - (4 x (C-Br) + 1 x (C-C) = - (4 x 276 + 1 x 347) = - 1,451 kJ (minus means that the energy is released during the reaction)

Hence the ΔH°ᵣₓₙ is 1,223 kJ + (-1,451) kJ = - 228 kJ

You might be interested in

Draw the molecule by placing atoms on the grid and connecting them with bonds. Include all lone pairs of electrons. Show the for

Alexus [3.1K]

Answer:

See explanation below

Explanation:

In this case, let's see both molecules per separate:

In the case of SeO₂ the central atom would be the Se. The Se has oxidation states of 2+, and 4+. In this molecule it's working with the 4+, while oxygen is working with the 2- state. Now, how do we know that Se is working with that state?, simply, let's do an equation for it. We know that this molecule has a formal charge of 0, so:

Se = x

O = -2

x + (-2)*2 = 0

x - 4 = 0

x = +4.

Therefore, Selenium is working with +4 state, the only way to bond this molecule is with a covalent bond, and in the case of the oxygen will be with double bond. See picture below.

In the case of CO₂ happens something similar. Carbon is working with +4 state, so in order to stabilize the charges, it has to be bonded with double bonds with both oxygens. The picture below shows.