Use the table below to calculate the change in enthalpy (bond energy) for the reaction above.

To calculate the change in enthalpy (\( \Delta H \)) for a chemical reaction using bond energies, you can follow these steps:

1. Identify the bonds broken and formed in the reaction.
2. Use the provided bond energies to calculate the total energy of bonds broken and the total energy of bonds formed.
3. Calculate the change in enthalpy using the formula: \[ \Delta H = (\text{Energy of bonds broken}) - (\text{Energy of bonds formed}) \]

Example Calculation

For a hypothetical reaction: \[ \text{Reactants} \rightarrow \text{Products} \]

Suppose the reaction involves breaking and forming the following bonds:

• Bonds broken (assuming):

  • 2 O-H bonds (from water or some alcohol)
  • 1 C-H bond (from an alkane)

• Bonds formed (assuming):

  • 1 O=O bond (from molecular oxygen)
  • 1 C=O bond (from a carbonyl compound)

Step-by-Step Calculation

Step 1: Determine the bonds involved.

• Bonds broken:
  • \( 2 , \text{O-H} \)
  • \( 1 , \text{C-H} \)

Step 2: Calculate energy for bonds broken.

• Energy for \( 2 , \text{O-H} \): \[ 2 \times 464 , \text{kJ/mol} = 928 , \text{kJ/mol} \]

• Energy for \( 1 , \text{C-H} \): \[ 1 \times 411 , \text{kJ/mol} = 411 , \text{kJ/mol} \]

• Total energy of bonds broken: \[ 928 , \text{kJ/mol} + 411 , \text{kJ/mol} = 1339 , \text{kJ/mol} \]

Step 3: Calculate energy for bonds formed.

• Bonds formed:

  • \( 1 , \text{O=O} \)
  • \( 1 , \text{C=O} \)

• Energy for \( 1 , \text{O=O} \): \[ 1 \times 494 , \text{kJ/mol} = 494 , \text{kJ/mol} \]

• Energy for \( 1 , \text{C=O} \): \[ 1 \times 799 , \text{kJ/mol} = 799 , \text{kJ/mol} \]

• Total energy of bonds formed: \[ 494 , \text{kJ/mol} + 799 , \text{kJ/mol} = 1293 , \text{kJ/mol} \]

Step 4: Calculate \( \Delta H \) for the reaction. \[ \Delta H = (\text{Energy of bonds broken}) - (\text{Energy of bonds formed}) \] \[ \Delta H = 1339 , \text{kJ/mol} - 1293 , \text{kJ/mol} = 46 , \text{kJ/mol} \]

Conclusion

The change in enthalpy (\( \Delta H \)) for this hypothetical reaction is \( +46 , \text{kJ/mol} \), indicating that the reaction is endothermic. Adjust your bonds broken and formed as per the actual reaction you are analyzing.