Calculate the C—C bond energy from the following data:
`2C ("graphite") + 3H_2(g) to C_2H_6(g) , DeltaH = -84.67 kJ`
`C("graphite"), to C(g) DeltaH = 716.7kJ`
`H_2(9g) , to 2H(g) Delta= 435.9 kJ`
Assume 416 as the C - H bond energy.

Explanation

To calculate the C—C bond energy from the given data, we will follow these steps:

### Step 1: Write the given reactions and their enthalpy changes.

1. **Formation of Ethane (C2H6)**:
\[ 2C (\text{graphite}) + 3H_2(g) \rightarrow C_2H_6(g) \quad \Delta H = -84.67 \, \text{kJ} \]
...