Bond energy

The average bond enthalpies for O-O = 146, O=O = 496, O-H = 463 kJ/mol. What is the enthalpy change, in kJ, for the reaction below?

H₂O₂(g) → H₂O(g) + ½O₂(g)

• -102

• +102

• +350

• +394

The following equation shows the formation of magnesium oxide from magnesium metal. Which statement is correct for this reaction?

2Mg(s) + O₂(g) → 2MgO(s) ΔH = -1204 kJ

• 1204 kJ of energy are released for every mole of magnesium reacted

• 602 kJ of energy are absorbed for every mole of magnesium oxide formed

• 602 kJ of energy are released for every mole of oxygen reacted

• 1204 kJ of energy are released for every two moles of magnesium oxide formed

Using the table of average bond energies below the image, the ΔH for the reaction in kJ is.....

• + 160 kJ
• -63 kJ
• - 160 kJ
• +217 kJ

Using the reaction & table above, determine the change in energy and whether or not the reaction is endothermic or exothermic:

• -2023 kJ/mol endothermic

• 2023 kJ/mol endothermic

• -2023 kJ/mol exothermic

• 2023 kJ/mol

  exothermic