8. Thermochemistry
Enthalpy of Formation
8. Thermochemistry Enthalpy of Formation
5PRACTICE PROBLEM
In two steps, ethanol (C2H5OH) is produced industrially from CO and H2. It is being considered for use as a precursor to hydrocarbon fuels like ethane (C2H6) because it is so inexpensive to produce:
Step 1. 2 CO(g) + 4 H2(g) → C2H5OH(l) + H2O(l) ΔS° = —687.5 J/K
Step 2. C2H5OH(l) → C2H6(g) + 1/2 O2(g) ΔS° = 68.5 J/K
What is the enthalpy of the reaction in kJ for step 1?
In two steps, ethanol (C2H5OH) is produced industrially from CO and H2. It is being considered for use as a precursor to hydrocarbon fuels like ethane (C2H6) because it is so inexpensive to produce:
Step 1. 2 CO(g) + 4 H2(g) → C2H5OH(l) + H2O(l) ΔS° = —687.5 J/K
Step 2. C2H5OH(l) → C2H6(g) + 1/2 O2(g) ΔS° = 68.5 J/K
What is the enthalpy of the reaction in kJ for step 1?