Final answer:
To find the enthalpy change for the decomposition of 1 mole of hydrogen peroxide into water and oxygen gas, you can use standard enthalpies of formation in conjunction with Hess's Law to calculate the total reaction enthalpy.
Step-by-step explanation:
The decomposition of hydrogen peroxide (H₂O₂) into water (H₂O) and oxygen gas (O₂) involves the breaking of chemical bonds in H₂O₂ and the formation of new bonds in H₂O and O₂. The enthalpy change for this chemical change can be determined using a Hess cycle and standard enthalpies of formation. To calculate the enthalpy change of reaction for the decomposition of exactly 1 mole of H₂O₂ under standard conditions, you would use the following reaction:
2H₂O₂(l) → 2H₂O(g) + O₂(g)
By applying Hess's Law and standard enthalpies of formation (ΔH°f) for each compound, we can calculate the total enthalpy change (ΔH°) for the reaction. Standard enthalpies of formation are tabulated values that represent the heat changes when one mole of a substance is formed from its elements in their standard states. The enthalpy change of reaction is calculated by summing up the enthalpy changes for the formation of products and subtracting the enthalpy changes for the reactants.