Answer :
Answer:
There is 582 kJ of energy released. Δ H rxn for 500g= − 582 kJ ( negative because the energy is released).
Explanation:
Step 1: The balanced equation
CaO(s)+ H2O(l) → ca(OH)2 ΔH= -65.2 kJ
In this situation, 1 mole of CaO consumed, needs 1 mole of H2O to produce 1 mole of Ca(OH)2
The enthalpy change of this reaction is Δ H rxn = − 65.2 kJ
This means the reaction gives off 65.2 kJ of heat when 1 mole of CaO and 1 mole of H2O react.
Step 2: Calculate number of moles in 500 g of CaO
Number of moles = mass of CaO / Molar mass of CaO
Number of moles = 500 grams / 56.077 g/mol = 8.92 moles
Step 3: Calculate energy released
Since there is released 65.2 kJ when 1 mole of CaO reacts; for 8.92 moles of CaO there will be released 8.92 * 65.2 kJ = 581.584 ≈ 582 kJ
.
There is given off 582 kJ of energy
Δ H rxn for 500g= − 582 kJ