ENGR 1130Project D: Fuels and Coolants: Thermochemistry

25 Points        See Grading Rubric in Canvas

Why is my teacher having me do this project??

A. To practice Thermochemistry Calculations for chemical reactions. (Module 9)

B. To practice phase change calculations using heats of vaporization and fusion and heat capacities. (M9)

C. To develop an understanding of properties thermodynamically conducive to fuels and coolants.(Module 9)

You have been assigned a compound from the chart posted on the Project D Page in Canvas. You must do the compound you are assigned. This is the same compound you were assigned in Project C (Parts C and D). Yea! The Lewis Structure is done!

***Clearly show all calculations and go into detail to receive maximum points on this project.

Part A: Calculating DH^o_rxn from heats of formation

1.Write the balanced chemical equation for the combustion of your compound. From the equation and the values from Appendix G of your text, calculate the DH^o for this reaction (assume standard conditions).

• You will probably need to research the DH_f^o for your particular compound. At the end of this document are some good sites with comprehensive thermochemical data.
  • If your compound has nitrogen in it, please add nitrogen gas (is it a HOFBrINCl?) to the products.
  • If your compound has chlorine or fluorine in it, please add these elemental gases (are they HOFBrINCl?) to the products.

Part B: Calculating DH^o_rxn from bond dissociation energies.

2. Rewrite the balanced chemical equation from Part A, drawing the Lewis structures of all the compounds involved instead of just writing the formulas.

• Create a Bonds Broken and Bonds Formed table and record your data. (See the Example below)

Type of Bond Broken (Reactant Bonds)	Quantity of Bond Type	Type of Bond Formed (Product Bonds)	Quantity of Bond type
C-H		C=O

3. Using the Bond Energies, calculate the DH^o_rxn for the combustion reaction. You can find a chart of Bond Dissociation Energies in Section 7.5 (Tables 7.2 and 7.3) of your text. Section 7.5 also has some examples of this type of calculation.

• Clearly show your work. It may be easier to show your work by modifying your chart in 2 (adding in the bond energy values and the total DH from each compound)
• DH^orxn = SD(bonds broken) – SD(bonds formed)

4. Compare the values from Parts A and B. Try to account for any differences.

• If you have significant differences, which calculation do you think is more accurate?

Part C: Phase Change Diagrams and Calculation

5. Draw a phase change diagram (like the one below) labeling the temperatures at which the phase changes occur. Do not copy this diagram, create your own. On your diagram indicate what is happening at each part (letters A, B, C, D, E)—like what phase change (verb) and what states of matter are present.

6. Research the heats of fusion and vaporization and heat capacities for the solid, liquid, and gas phases for your compound. Calculate the amount of energy needed to convert 1 kilogram of your substance from the solid phase all the way to the gas phase. (Choose a starting temperature below the melting point and an ending temperature higher than the boiling point.)

Part D: Compound Analysis

7. Would your compound be a good choice to be used as a fuel? rocket fuel? airplane fuel?

• Using your value from Part A—determine the energy density of your compound. (kJ/gram)
• How does this energy density compare to other fuels?
  • Choose two commonly used fuels and compare.

8. Would your compound be a good choice to be used as a coolant? Why or why not?

• Use your work from Part C to support your answer.
• Compare your compound to two typical coolants. How do your compound’s properties compare to common coolants?
• What are qualities of “good” coolants?
• In what engineering applications are coolants needed/used?

Part E: Citations

Cite ALL your sources. You can hyperlink them, but I also need the citations. This should be a section at the end of your document.

Websites for finding good thermochemical data.

National Institute of Standards and Technology: NIST Chemistry WebBook

NIH National Library of Medicine: PubChem