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ChE 125 Chemical Reaction Engineering

Department of Chemical Engineering University of the Philippines Diliman

Problem Set #1

PROBLEM 1 C. Cristallini, A. Villani, L. Lazzeri, G. Ciardelli, and A. S. Rubino [ Polym. Int., 48, 63-68 (1999)] used dilatometry to monitor the kinetics of the homopolymerization of sodium acrylate in aqueous solution at 50°C . A cathetometer was employed to generate the data tabulated below. The initial concentration of sodium acrylate is 0.4 M. Time (min) 0 5 10 15 20 25

Height of meniscus (cm) 0.304 0.515 0.726 0.887 1.063 1.178

Time (min) 30 35 40 45 50 inf

Height of meniscus (cm) 1.307 1.418 1.513 1.593 1.680 3.617

Determine the order of sodium acrylate. What is the value of the rate constant?

PROBLEM 2 S. Mittal, V. Sharma, and K. Banerji [Int. J. Chem. Kinet., 18, 689-699 (1986)] studied the oxidation of propanol (A) with Nchloroethylcarbamate (B) in acid solution:

A + 2B ® C + D + 2E a.

The following data are characteristic of this reaction at 30°C. Determine the integers that characterize the orders of this reaction with respect to each of the reactants and the reaction rate constant. A (mol/L) 0.5 0.5 0.5 0.5 0.5 0.5 0.1 0.2 0.3 0.7 0.9

b.

B x 103 (mol/L) 2.0 5.0 7.5 10.5 12.5 15.0 5.0 5.0 5.0 5.0 5.0

Rate x 108 (mol/ L s) 2.66 6.15 9.45 12.60 15.40 17.85 1.25 2.46 3.78 8.65 11.30

Analyze the following values of the rate constant to determine the activation energy and frequency factor.

Temperature (°𝐶) 25 30 35 40 45

Rate constant x 105 1.66 [from part (A)] 3.55 5.11 7.27

PROBLEM 3 S. D. Furrow [INt. J. Chem. Kinet., 14, 927-932 (1982)] studied the kinetics of the hydrozy iodination of 2-butenoic acid (B) in aqueous solution:

2I 2 + B + I O3- + H + + 2H 2O ® 5C

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a.

Furrow used absorbance measurements to monitor the concentration of I 2 as a function of time for an experiment in which the initial concentrations of I2, B, IO3-, and H+ were 1.98x10-4, 0.10, 0.025, and 0.10 M, respectively. If the rate expression is of the form:

r = k(I 2 )m (B )n (I O3- )p (H + )q Time (s) 0 35 96 232 339 588 824

I2 x 104 (mol/L) 1.98 1.94 1.84 1.68 1.56 1.28 1.06

Time (s) 1060 1290 1530 1760 2000 2250 2500

I2 x 104 (mol/L) 0.856 0.650 0.479 0.350 0.250 0.145 0.063

where the various orders are either integers or half-integers, use the following data to determine the order of this reaction with respect to I2, and the corresponding value of the pseudo-mth order rate constant. What assumptions must be made to arrive at numerical values of these parameters? b.

From analyses of the type conducted to determine the order of the reaction with respect to I 2, Furrow reported the values of the pseudo-mth order rate constant tabulated below. IO3 (M) 0.0250 0.0250 0.0250 0.0250 0.00625 0.0500

B (M) 0.025 0.005 0.100 0.100 0.100 0.100

H+ (M) 0.0985 0.0985 0.0493 0.0197 0.0985 0.0985

kpseudo x 105 0.442 0.203 0.458 0.175 0.375 1.460

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