To solve this problem, we need to reverse the given chemical reaction and determine the enthalpy change for the reversed reaction. Let's analyze step-by-step:
1. Understand the Original Reaction and its Enthalpy Change:
- The given reaction is:
[tex]\[
H_2 + 0.5 O_2 \rightarrow H_2O
\][/tex]
- The enthalpy change ([tex]\(\Delta H\)[/tex]) for this reaction is [tex]\(-286 \, \text{kJ}\)[/tex].
2. Reverse the Reaction:
- Reversing the reaction means flipping the reactants and products:
[tex]\[
H_2O \rightarrow H_2 + 0.5 O_2
\][/tex]
3. Determine the New Enthalpy Change:
- When reversing a chemical reaction, the sign of the enthalpy change also reverses. The original reaction had an enthalpy change of [tex]\(-286 \, \text{kJ}\)[/tex].
- Reversing the reaction changes the sign of [tex]\(\Delta H\)[/tex]:
[tex]\[
\Delta H_{reversed} = -(-286 \, \text{kJ}) = 286 \, \text{kJ}
\][/tex]
Thus, the enthalpy change for the reversed reaction is [tex]\(286 \, \text{kJ}\)[/tex].
4. Select the Correct Answer:
- Among the given choices, the correct answer is:
[tex]\[
\text{A. } 286 \, \text{kJ}
\][/tex]
