Question

(ii) iodine and bromine react at high temperatures to form iodine monobromide, \\(\text{ibr}\\).

the equation is shown.

\\\text{i}_2(\text{g}) + \text{br}_2(\text{g}) \
ightarrow 2\text{ibr}(\text{g})\\

the structures of the molecules involved in the reaction are \\(\text{i}-\text{i}\\), \\(\text{br}-\text{br}\\) and \\(\text{i}-\text{br}\\).

table 6.1

bond	bond energy in kj/mol
\\(\text{br}-\text{br}\\)	193
\\(\text{i}-\text{br}\\)	175

calculate the enthalpy change, \\(\delta h\\), for the reaction using the bond energies in table 6.1.

use the following steps.

• calculate the total amount of energy required to break the bonds in 1 mol of \\(\text{i}_2(\text{g})\\) and 1 mol of \\(\text{br}_2(\text{g})\\).

\\(\text{.................................................. kj}\\)

• calculate the total amount of energy released when the bonds in 2 mol of \\(\text{ibr}(\text{g})\\) are formed.

\\(\text{.................................................. kj}\\)

• calculate the enthalpy change, \\(\delta h\\), for the reaction. your answer should include a sign.

\\(\text{.................................................. kj/mol}\\)
3

Explanation:

Calculate energy required to break bonds

$$
LATEXBLOCK0
$$

Calculate energy released when bonds form

$$
LATEXBLOCK1
$$

Calculate enthalpy change

$$
LATEXBLOCK2
$$

Answer:

Question 1

Calculate the total amount of energy required to break the bonds in \(1\text{ mol}\) of \(\text{I}_2\text{(g)}\) and \(1\text{ mol}\) of \(\text{Br}_2\text{(g)}\).
Answer: <blank>343</blank> \(\text{kJ}\)

Question 2

Calculate the total amount of energy released when the bonds in \(2\text{ mol}\) of \(\text{IBr(g)}\) are formed.
Answer: <blank>350</blank> \(\text{kJ}\)

Question 3

Calculate the enthalpy change, \(\Delta H\), for the reaction. Your answer should include a sign.
Answer: <blank>-7</blank> \(\text{kJ/mol}\)