ANSWER
[tex]\text{ }\Delta E_{REVERSE}\text{ = 31 KJ/mol}[/tex]
EXPLANATION
Given information
The energy on the product side = -40 KJ
The energy on the reactant side = -9kJ
Assume the reaction is a reversible reaction
[tex]\text{ A }\rightleftarrows\text{ B}[/tex]
For a reverse reaction, the product becomes the reactant and the reactant is the new product formed
Step 1: Write the general formula for calculating a change in energy
[tex]\text{ }\Delta E_{reverse}\text{ = }\Delta E_{PRODUCT}-\text{ }\Delta E_{REACTANT}[/tex]
Step 2: Substitute the given data into the formula in step 1
[tex]\begin{gathered} \Delta E_{reverse}\text{ = -9 - \lparen-40\rparen} \\ \Delta E_{REVERSE\text{ }}\text{ = -9 + 40} \\ \text{ }\Delta E_{reverse\text{ }}\text{ = 31 KJ/mol} \end{gathered}[/tex]
