BuyFindarrow_forward

Chemistry & Chemical Reactivity

10th Edition
John C. Kotz + 3 others
ISBN: 9781337399074

Solutions

Chapter
Section
BuyFindarrow_forward

Chemistry & Chemical Reactivity

10th Edition
John C. Kotz + 3 others
ISBN: 9781337399074
Textbook Problem

Based on ΔrH° and ΔrS°, predict the spontaneity of the reaction of hydrogen and chlorine to give hydrogen chloride gas under standard conditions (at 298 K). Calculate ΔS° (universe) to verify your prediction.

H 2 ( g ) + C l 2 ( g ) 2   H C l ( g )

Interpretation Introduction

Interpretation:

The ΔSo(universe) for the reaction of hydrogen and chlorine that results in formation of hydrogen chloride gas should be calculated. It should be identified that the calculated ΔS(universe) value is in accordance with the predicted spontaneity of the reaction.

Concept introduction:

The universe consists of two parts, systems and surroundings. The entropy change for the universe is the sum of entropy change for the system and for surroundings.

  ΔSo(universe)= ΔSo(system)+ΔSo(surroundings)

The ΔS(universe) should be greater than zero for a spontaneous process.

The  ΔS(system) calculated by using the following expression,

  ΔSo(system)rS°=nS°(products)nS°(reactants)

The ΔSo(surroundings) calculated by using the following expression,

  ΔSo(surroundings)rHoT

Here, ΔrHo is the enthalpy change for the reaction and T is the temperature.

Explanation

The calculation of ΔSo(universe) for the reaction of hydrogen and chlorine to give hydrogen chloride gas is calculated below.

Given: H2(g)+Cl2(g)2HCl(g)

The Appendix L was referred for the values of entropies and enthalpies.

The standard entropy of H2(g) is 130.7 J/Kmol

The standard entropy of Cl2(g) is 223.08 J/Kmol

The standard entropy of HCl(g) is 186.2 J/Kmol

The standard enthalpy of H2(g) is 0 kJ/mol

The standard enthalpy of Cl2(g) is 0 kJ/mol

The standard enthalpy of HCl(g) is -92.31 kJ/mol

The balanced chemical equation is: H2(g)+Cl2(g)2HCl(g)

Calculation for ΔSo(system):

The  ΔSo(system) can be calculated by the following expression,

  ΔSo(system)= ΔrS° = nS°(products)nS°(reactants)

  ΔSo(system)=[(2 mol HCl(g)/mol-rxn)S°[HCl(g)]-[(1 mol H2(g)/mol-rxn)S°[H2(g)]+(1 mol Cl2(g)/mol-rxn)S°[Cl2(g)]]]

Substituting the entropy values referred from appendix L results to yield the answer as follows,

  ΔrS°=[(2 mol HCl(g)/mol-rxn)(186.2 J/K×mol)-[(1 mol H2(g)/mol-rxn)(130.7 J/K×mol)+(1 mol Cl2(g)/mol-rxn)(223.08 J/K×mol)]]=18

Still sussing out bartleby?

Check out a sample textbook solution.

See a sample solution

The Solution to Your Study Problems

Bartleby provides explanations to thousands of textbook problems written by our experts, many with advanced degrees!

Get Started

Chapter 18 Solutions

Show all chapter solutions add

Additional Science Solutions

Find more solutions based on key concepts

Show solutions add

Energy-yielding nutrients include all of the following except. a. vitamins b. carbohydrates c. fat d. protein

Nutrition: Concepts and Controversies - Standalone book (MindTap Course List)

A standard unit must have what characteristics?

An Introduction to Physical Science

What are sister chromatids?

Human Heredity: Principles and Issues (MindTap Course List)

Explain how a hot-air balloon works in terms of gas densities.

Chemistry for Today: General, Organic, and Biochemistry