# EXAM 6 - This print-out should have 16 questions...

This preview shows pages 1–3. Sign up to view the full content.

Johnson, Chelsea – Homework 11 – Due: Apr 25 2007, 11:00 pm – Inst: Walker 1 This print-out should have 16 questions. Multiple-choice questions may continue on the next column or page – find all choices before answering. The due time is Central time. Read all of the options before choosing one. There may be cases in which more than one response appears to be true. PICK THE RE- SPONSE THAT BEST answers the question asked. 001 (part 1 of 1) 3 points Which of the following statements about re- acting molecules is true? 1. The transition state energy is usually the average between the energies of the reactants and products. 2. All molecules in a gas sample at a specific temperature have the same energy. 3. When two reactant molecules collide they must react. 4. An effective collision between two molecules must be oriented correctly. cor- rect Explanation: A collision between molecules results in a reaction if they collide with enough energy and an effective orientation. 002 (part 1 of 1) 3 points Activation energy for an elementary process 1. is part of the net enthalpy change for the reaction. 2. is the energy required to produce the transition state from the reactants. correct 3. is smaller for slower reactions and larger for faster reactions. 4. None of these Explanation: E a reactants products transition state Reaction progress Potential energy When the reactants gain enough energy to equal the energy of activation the transition state is formed. 003 (part 1 of 2) 3 points Consider the following potential energy dia- gram. 40 80 120 160 energy, kJ reaction progress A + B AB What is the value of Δ H ? Correct answer: - 30 kJ. Explanation: The final energy for AB is 50 kJ. The initial energy for A + B is 80 kJ. Δ H = final - initial = 50 - 80 = - 30 kJ 004 (part 2 of 2) 3 points What is the activation energy E a for this re- action? Correct answer: 100 kJ. Explanation: The maximum energy (top of “hill”) is 180 kJ. The initial energy for A + B is 80 kJ.

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

View Full Document
Johnson, Chelsea – Homework 11 – Due: Apr 25 2007, 11:00 pm – Inst: Walker 2 E a = maximum - initial = 180 - 80 = 100 kJ 005 (part 1 of 1) 3 points The overall reaction NO 2 (g) + CO(g) NO(g) + CO 2 (g) is proposed to proceed by the mechanism 2 NO 2 (g) NO 3 (g) + NO(g) slow NO 3 (g) + CO(g) NO 2 (g) + CO 2 (g) fast Which of the following rate laws would be consistent with this mechanism?
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