Question

Use Hess’s Law to calculate ΔHo for the reaction: Fe2O3 + 3 CO → 2 Fe + 3 CO2, given: 4 Fe + 3 O2 → 2 Fe2O3 ΔHo = –1650 kJ CO + ½ O2 → CO2 ΔHo = –280 kJ

Answer 1

To calculate the enthalpy change (ΔHo) for the reaction, we can use Hess's Law to manipulate the given reactions and obtain the desired equation. By reversing equation 1 and multiplying equation 2 by 2, we can add the two equations together to calculate the enthalpy change for the desired reaction, which is -345.0 kJ/mol.

Step-by-step explanation:

We can use Hess's Law to calculate the enthalpy change (ΔHo) for the reaction: Fe2O3 + 3 CO → 2 Fe + 3 CO2. Given the following reactions and their enthalpy changes:

1. 4 Fe + 3 O2 → 2 Fe2O3 ΔHo = -1650 kJ/mol
2. CO + ½ O2 → CO2 ΔHo = -280 kJ/mol

We need to manipulate these equations to obtain the desired equation. We can reverse equation 1 and multiply equation 2 by 2 to balance the number of CO and Fe2O3:

1. 2 CO → 2 C + O2 ΔH = 221.0 kJ/mol
2. 2 C + O2 → 2 CO2 ΔH = -566.0 kJ/mol

Now we can add these two equations together:

2 CO + O2 → 2 CO2 ΔHo = 221.0 kJ/mol + (-566.0 kJ/mol) = -345.0 kJ/mol

Therefore, the ΔHo for the given reaction is -345.0 kJ/mol.