Question

10. Samples of a new anticancer drug in aqueous solution were stored at 45°C, 60°C and 75°C. The first-order rate constants for the decomposition at different temperatures were determined as follows: 45 60 75 Temperature (°C) Rate Constant (day'') 0.052 0.069 0.089 Considering that the drug expires once the concentration decreases to 90% of the original, calculate the expiration time of the anticancer drug at 25°C (room temperature).
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Answer 1

According to Arrehinius equation, Arrhenius in the needle It to) Eu R= Activation energy Gas constant T, = 45° C = US +273 = 318 K Te = 60°C = 60 +273 = 333K ki = 0.052 day- Kz = 0.069 day! In = 0.069 0.052 333-318 KI 333 x 318 K 8.314 TK Mol Eas 16602 Jmurta 16.602 kJ/mol k, = ? Now, T.: 25°C - 25 +243 = 298 K Ja=us'c = 318k K₂ = 0.052 day" 16602 J mai K2 = 318 - 298 K 1 318x 298 k² 8-314 J Kimont In A = -0.42144 -02 0.42144 ki = 0.052 day- x é de I k, = 0.034 day- for 1st order reaction, A = 100 kt = In Ao At = 90 - At :obzu days in any one *3.089 days Expiration time of anticancer drug is 3 days.