Answer the questions on Hess's Law listed below. Please notethat you must include units throughoutall of your calculations and provide your answer inscientific notation to the correct numberof significant digits.
Click on the red flags to the left to review content onscientific notation and significant digits.
Question 1
Iron is made from a reaction of iron oxide with carbon monoxidein the following reaction:
Fe2O3(s) + 3CO(g) → 2 Fe(s) + 3CO2(g)
Using Hess' Law, calculate the enthalpy of reaction given:
| C(s) + O2(g) →CO2(g) | | ΔH = -393.5 kJ /mol |
| 2 Fe(s) + 3/2 O2(g) →Fe2O3(s) | | ΔH = -824.2 kJ /mol |
| C(s) + 1/2 O2(g) →CO(g) | | ΔH = -110.5 kJ /mol |
Question 2
Use Hess' Law to calculate enthalpy of reaction for thefollowing equation:
2 N2(g) + 5 O2(g) → 2N2O5(g)
Given:
| 2 H2(g) + O2(g) → 2H2O(l) | | ΔH = -571.6 kJ /mol |
| N2O5(g) +H2O(l) → 2HNO3(l) | | ΔH = -76.6 kJ /mol |
| 1/2 N2(g) + 3/2 O2(g) +1/2 H2(g) → HNO3(l) | | ΔH = -174.1 kJ /mol |
Question 3
Using standard enthalpies of formation, determine theΔHreaction for the following equations:
2 CH3OH(l) + 3O2(g) → 2 CO2(g) + 4H2O(g)
| Standard Enthalpies of Formation |
|---|
| Compound | ΔHf (kJ/mol) |
|---|
| CO(g) | -110.5 |
|---|
| CO2(g) | -393.5 |
|---|
| CH3OH(l) | -238.4 |
|---|
| H2O(g) | -241.8 |
|---|
