Homework 11

Download Document
Showing pages : 1 - 3 of 4
This preview has 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.

Unformatted text preview: ycs73 Homework 11 Fakhreddine (53605) 1 This print-out should have 14 questions. Multiple-choice questions may continue on the next column or page fnd all choices be±ore answering. 001 10.0 points Which o± the ±ollowing statements about re-acting molecules is true? 1. An e²ective collision between two molecules must be oriented correctly. cor-rect 2. When two reactant molecules collide they must react. 3. All molecules in a gas sample at a specifc temperature have the same energy. 4. The transition state energy is usually the average between the energies o± the reactants and products. Explanation: A collision between molecules results in a reaction i± they collide with enough energy and an e²ective orientation. 002 10.0 points Activation energy ±or an elementary process 1. is smaller ±or slower reactions and larger ±or ±aster reactions. 2. is part o± the net enthalpy change ±or the reaction. 3. is the energy required to produce the transition state ±rom the reactants. correct 4. None o± these Explanation: E a reactants products transition state Reaction progress Potential energy When the reactants gain enough energy to equal the energy o± activation the transition state is ±ormed. 003 (part 1 o± 2) 10.0 points Consider the ±ollowing potential energy dia-gram. 40 80 120 160 energy, kJ reaction progress A + B AB What is the value o± Δ H ? Correct answer: 10 kJ. Explanation: The fnal energy ±or AB is 20 kJ. The initial energy ±or A + B is 30 kJ. Δ H = fnal initial = 20 30 = 10 kJ 004 (part 2 o± 2) 10.0 points What is the activation energy E a ±or this re-action? Correct answer: 150 kJ. Explanation: The maximum energy (top o± hill) is 180 kJ. The initial energy ±or A + B is 30 kJ. ycs73 Homework 11 Fakhreddine (53605) 2 E a = maximum initial = 180 30 = 150 kJ 005 10.0 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 ...
View Full Document