Enthalpy from Bond Energy Video

Which process requires energy and which process releases energy?

4 Fe + 3 O₂ → 2 Fe₂O₃ Bonds are formed so energy is (a)   .

2 NH₃ → N₂ + 3 H₂ Bonds are broken so energy is​ (b)   .

• RELEASED
• REQUIRED

How many O₂ (O=O) bonds are going to break in this reaction?

• 1

• 2

• 4

Select the bonds that are going to form on the products side of the reaction.

• C - O

• C = O

• C - H

• O - H

Do the calculation...

ΔH_rxn = [1652 + 990] - [1598 + 1852]

Select the correct answer

• 404 kJ/mol

• 808 kJ/mol

• 0 kJ/mol

• -808 kJ/mol

Do the calculation...

ΔH_rxn = [826 + 839 + 431] - [1239 + 614 + 328]

What is the enthalpy change (ΔH) for this reaction?

• -85 kJ/mol

• -10 kJ/mol

• 0 kJ/mol

• 10 kJ/mol