Answered: Chemistry Question

Chemistry

10th Edition

ISBN:9781305957404

Author:Steven S. Zumdahl, Susan A. Zumdahl, Donald J. DeCoste

Publisher:Steven S. Zumdahl, Susan A. Zumdahl, Donald J. DeCoste

Chapter1: Chemical Foundations

Section: Chapter Questions

Problem 1RQ: Define and explain the differences between the following terms. a. law and theory b. theory and...

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Step 1 Introduction

The randomness or disorders of the surroundings modifies when additional heat is added to it or absorbed from it. So, the entropy change of the surroundings increases when the reaction is exothermic i.e., the released heat energy (enthalpy) is added to the surroundings thereby causing the entropy change. The relationship between the entropy change of the surroundings and the enthalpy change of the reaction is given by the following relation

$△ S_{s u r r o u n d i n g} = \frac{- △ H_{r x n}}{T}$

$\begin{array}{l} △ S_{s u r r o u n d i n g} - E n t r o p y c h a n g e o f s u r r o u n d i n g \\ △ H_{r x n} - E n t h a l p y c h a n g e o f r e a c t i o n \\ T - T e m p e r a t u r e \end{array}$

P.S.: When calculating entropy change of surroundings, the enthalpy change of the reaction should be in J not KJ.

Step 2 Solution

Temperature = 25^oc

Temperature = 273 +25 K=298K

$\begin{matrix} \begin{array}{rcl} △ S_{s u r r o u n d i n g} & = & \frac{- △ H_{r x n}}{T} \\ = & \frac{- (- 183000)}{273 + 25} \\ = & \frac{183000}{298} \\ = & 614.09 J K^{- 1} \end{array} \end{matrix}$

The negative sign in the relation modifies the entropy change to positive since exothermic reaction heats the surroundings causing an increase in entropy.