I want to know the enthalpy change for this reaction which occurs in a blast furnace:
Fe2O3(s) + 3C(s) --> 2Fe(l) + 3CO(g)
You will need the heat of formation for CO, and ironIIIoxide, and the heatofmelting for iron. I suspect you have some temperature in mind also which this reaction occurs, as it will not likely occur at 25C.
We will be happy to critique your work or thinking.
I have found the heat of formation for CO and Fe2O3, but I cannot find the heat of melting for iron and I'm not really sure where to look. When I have all of the information would you suggest constructing a Hess's cycle to calculate the enthalpy change for the reaction?
You can find the heat of fusion for iron here.
http://en.wikipedia.org/wiki/Iron
To find the heat of fusion for iron, you can search for it on the internet or consult reliable sources such as scientific textbooks or journals. One way to search for it is by searching for "heat of fusion of iron" or "enthalpy of fusion of iron". This should give you the specific value for the heat of fusion of iron.
Once you have the necessary heat of formation values for CO and Fe2O3, as well as the heat of fusion of iron, you can proceed to calculate the enthalpy change for the reaction using Hess's Law. Hess's Law states that the overall enthalpy change for a reaction is independent of the pathway taken and depends only on the initial and final conditions.
To construct a Hess's cycle for this reaction, you will need to consider the intermediate steps involved. Here are the steps you can take to calculate the enthalpy change using a Hess's cycle:
1. Write the balanced equations for the reactions involved in the cycle:
a. Fe2O3(s) + 3C(s) → 2Fe(l) + 3CO(g) (target reaction)
b. 2Fe(s) + 3/2O2(g) → Fe2O3(s) ΔH1 (reverse the formation reaction of Fe2O3)
c. 2Fe(s) → 2Fe(l) ΔH2 (use the heat of fusion of iron)
d. C(s) + O2(g) → CO2(g) ΔH3 (use the heat of formation for CO2)
e. CO(g) + 1/2O2(g) → CO2(g) ΔH4 (reverse the formation reaction of CO)
2. Determine the overall enthalpy change by summing the enthalpy changes of the individual reactions, using the coefficients to balance the equations.
ΔH(target) = ΔH1 + ΔH2 + ΔH3 + ΔH4
3. Substitute the known values for heat of formation and heat of fusion in their respective reactions. You might need to multiply or divide the reactions to adjust the stoichiometric coefficients.
4. Calculate the overall enthalpy change using the values found in step 3.
Remember to pay attention to the signs of the enthalpy values (positive/negative) and units (usually given in kJ/mol or kJ/g). It's also important to consider any state changes (solid to liquid, gas, etc.) as they contribute to the overall enthalpy change.