Question

only questions number: #3,6,8,16,19,22

Δι CH 122 - Practice Problems for Chapter 12 Do NOT use this problem set solely as test preparation. This problem set does NOT cover everything that we have discussed in class. You will still need to study class materials in order to do well on the learning assessment. 1. Of the following all are valid units for a reaction rate except A. moll B. M/S C. molhr D.g's E.molle 2. Which one of the following is not a valid expression for the rate of the reaction below? 4NH3 + 702 - 4NO2 + 6H20 1 [0] I ANO) 1 [ H0] 1 A[NH] A D. Δι Δι Δι E. All of the above are valid expressions of the reaction rate. 3. Based on the enthalpy changes and the activation energies and assuming that all collision factors are the same, which of the following reactions would be the fastest? Circle ONE answer. A. AH = 5J/mol; E. = 55 Jimol B. AH 10 J/mol; E,- 45 Jimol C. CH = +10 Jimol: E. = 35 kJ/mol 4. According to collision theory, why is the frequency factor not simply the number of collisions between reactants per unit time? A. because molecules repel one another when they get too close, thus preventing a reaction B. because some collisions do not break the important bonds in the reactants C. because not all collision have enough energy to produce a reaction D. because reactants have to collide in the proper orientation for the reaction to occur E. because the reverse process must be considered 5. It rate = k [A[B]C), what are the units of the rate constant ()? Circle ONE answer. A B. MS! c. M's D. EM F. kis unitless 6. Which of the following is true? A. If we know that a reaction is an elementary reaction, then we know its rate law. B. The rate-determining step of a reaction is the rate of the fastest elementary step of its mechanism. C. For the overall reaction, the reaction order can be determined from the coefficients of reactants D. In a reaction mechanism, an intermediate is identical to a transition state. E. All of the above statements are true. 1

Answer 1

g care barrier related as rate reaction only depends upon potential activation and. energy (Ea). 1 Activation Eneay (8) 07) همه عملے Note : because 괴 ) Activation en energy increases , rate o f reaction Enthalpy freaction does not affect rate of reaction, linked with thermodynamics, which indicate at what degree the resets into product A1 = 4410J/mol Among the followry only est stalemet is touse. In a mulh'step reaction slowest elemening Stepis sate. determining step. Ans :-(A) للنه turn ans :- (c) Ea = = 35 kr mol 6 #

$ A + B - C rate = k[A]2 Apps tienen ( B' does not Ang : CB4ncreasing the concentraties of resclant B. As rate law does not associated with concentration of 'B', so a conch of the rate of reaction —2с Elementy steps are EK CAJUB] ° A B C + D ; Eq=985 'KI/mol Step 2: A +€ > f ; eq=2.5 kJ step-3 : F+D → Etc; ta = 12.5 ks affect N 2A + 13 Step 1: Rate mol mo? (A) overall reaction. Addi 2A + -> 20. which are not (B) intermediates are :: Species present in overall reacties. So, D, and E are intermedals species which do not post in reaction sy, 'Er is catalyst he rate = k CA]*[1835. : (co Catalyst (d) rate law ces Yes. (f) 4 PE &q=2.5105 &a=98.5 kJ/mol ca = 12:57 KS/mol Etc reaction Coordinate A+B

2A +BB -20 +D. led rate from the data law bei, dale=k [a]e[B]s. 098 0-075 zk [ocas] 0.0283 ? K 10.035)*10.01997 - Liis K[17s][ob2s)–Gi) g: 450 form (1) slij Y: 0.025 0:098 0.075 Cores 0:116. DO Yxlog Cound) 10.098 -0.075 0.019 0.97 1. । 0.116 0:119 from I ad ling X, 0.035 0.098 Q. 45 6.175 log og man kan Х = 2. z -1.39 0.69 So, (A) Experimental tale law rate =K[A] [B] Ani (B) som (B. 0.098 L2 = 3200 mal? see ka (0-035)2C0-023) Ko 3200_12 my? see

2 X (C) rate 0.020) 3200x (0.050 Irat 0.16. nollet Dne