Hess_s Law Problem

# Hess_s Law Problem - Hesss Law Problem done in class on...

This preview shows pages 1–2. Sign up to view the full content.

Hess’s Law Problem done in class on Tuesday, September 18, 2007 One way to find the heat of reaction for a “target reaction” is to take combustion analysis data for products and reactants within the target reaction, and then manipulate those separate reactions and their respective heats of reaction, so that by virtue of Hess’s Law we can derive the heat of reaction for the final target reaction: Here is the target reaction we are concerned with: 3C(g) + 4H 2 (g) CH 3 CH 2 CH 3 (g) ΔH rxn = ??? Now let’s consider the combustion reactions of the individual reactants and product: C(s) + O 2 (g) CO 2 (g) ΔH comb = –393.5 kJ/mol (this refers to the combustion of ONE mole of C(s), as per the reaction to the left) H 2 (g) + ½O 2 (g) H 2 O(g) ΔH comb = –285.8 kJ/mol (this refers to the combustion of ONE mole of H 2 (g), as per the reaction to the left) CH 3 CH 2 CH 3 (g) + 5O 2 (g) 3CO 2 (g) + 4H 2 O(g) ΔH comb = –2220.1 kJ/mol (this refers to the combustion of ONE mole of CH 3 CH 2 CH 3 (g) as per the reaction to the left)

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

### What students are saying

• As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

Kiran Temple University Fox School of Business ‘17, Course Hero Intern

• I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

Dana University of Pennsylvania ‘17, Course Hero Intern

• The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

Jill Tulane University ‘16, Course Hero Intern