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Chemical Kinetics - Practice Problems
- Which of the following graphs best describes the relationship between the a reaction and the temperature of the reaction? rate of
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- Describe the difference between the terms rate of reaction, rate law, and rate constant. Give an example of each.
- What are the units of the rate constant for the following reaction? 2NO 2 ( g ) โ N 2 O 4 ( g ) Rate = k [NO 2 ]^2
- Calculate the rate at which Nmoment in time when NO 2 O 4 is formed in the following reaction at the 2 is being consumed at a rate of 0.0592 M/s: 2NO 2 ( g ) โ N 2 O 4 ( g )
- NO reacts with H 2 according to the following equation: 2NO( g ) + 2H 2 ( g )โ N 2 ( g ) + 2H 2 O( g ) The mechanism for this reaction involves two steps: 2NO + H 2 โ N 2 + H 2 O 2 (slow step) H 2 O 2 + H 2 โ 2H 2 O (fast step) What is the experimental rate law for this reaction?
- The disproportionation of NO to N 2 O and NO 2 is third order in NO: 3NO( g ) โ N 2 O( g ) + NO 2 ( g ) Rate = k [NO] 3 This rate law is consistent with which of the following mechanisms? a) 3NO โ N 2 O + NO 2 (one-step) b) 2NON โ N 2 O 2 (slow step) 2 O^2 + NO^ โ^ N^2 O + NO^2 (fast step) c) 2NO N 2 O 2 (fast step) N 2 O 2 + NO โ N 2 O + NO 2 (slow step)
Chemistry 123/125 General Chemistry II
- The reaction in which NO 2 forms a dimer is second order in NO 2 : 2NO 2 ( g ) โ N 2 O 4 ( g ) Rate = k [NO 2 ]^2 Calculate the rate constant for this reaction if it takes 0.005 s for the initial concentration of NO 2 to decrease from 0.50M to 0.25M.
- The decomposition of hydrogen peroxide is first order in H 2 O 2 : 2H 2 O 2 ( aq ) โ 2H 2 O( l ) + O 2 ( g ) Rate = k [H 2 O 2 ] How long will it take for half of the H the rate constant for this reaction is 5.6 x 10 2 O 2 in a 10- (^2) s- (^1) ?-gal sample to be consumed if
- Calculate the rate constant for the following acid-base reaction if the half-life for this reaction is 0.0282 s at 25^0 C and the reaction is first order in the NH 4 +^ ion: NH 4 +( aq ) + H 2 O( l ) โ NH 3 ( aq ) + H 3 O+( aq )
- Use the following data to determine the rate law for the decomposition of N 2 O. 2N 2 O( g ) โ 2N 2 ( g ) + O 2 ( g ) [N 2 O] (M): 0.100 0.086 0.079 0.075 0.066 0.059 0.0 49 Time (s): 0 80 120 160 240 320 480
- Use the results of the preceding problem to calculate the rate constant for this reaction. Predict the concentration of N 2 O after 900 s.
- Dimethyl ether, CH following equation: 3 OCH3,, decomposes at high temperatures as shown in the CH 3 OCH 3 ( g ) โ CH 4 ( g ) + H 2 ( g ) + CO( g ) The following data were obtained when the partial pressure of CH studied as this compound decomposed at 500oC. Use these data to determine the 3 OCH 3 was order of this reaction. PCH3OCH3 (mmHg): 312 278 251 227 157 Time (s): 0 390 777 1195 3155
- The rate constant for the decomposition of N 2 O 5 increases from 1.52 x 10-5^ s-1^ at 250 C to 3.83 x 10 -3^ s-1^ at 45 0 C. Calculate the activation energy for this reaction.
- Calculate the activation energy for the following reaction if the rate constant forthis reaction increases from 87.1 M-1 (^) s-1 (^) at 500K to 1.53 x 10 3 M-1 (^) s-1 (^) at 650K:
2NO 2 ( g )โ 2NO( g ) + O 2 ( g )
- Calculate the activation energy for the decomposition of NOtemperature dependence of the rate constant for this reaction: 2 from the
2NO 2 ( g ) โ N 2 ( g ) + 2O 2 ( g ) Temperature (K): 319 329 352 381 389 k (M-^1 s-^1 ): 0.522 0.755 1.70 4.02 5.
- Calculate the rate constant at 780 K for the following reaction if the rate constantfor the reaction is 3.5 x 10-7 (^) M-1 (^) s-1 (^) at 550 K and the activation energy is 188 kJ/mol: 2HI( g ) โ H 2 ( g ) + I 2 ( g )
- Calculate the rate constant at 75for this reaction is 6.5 x 10-5 (^) M-1 (^) s (^0) -1^ C for the following reaction if the rate constant (^) at 25 0 C and the activation energy is 92. kJ/mol: CH 3 I( aq ) + OH -^ ( aq )โ CH 3 OH( aq ) + I-^ ( aq )
