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

Is the reaction Si(s) + 2 H2(g) → SiH4(g) spontaneous under standard conditions at 298.15 K? Answer this question by calculating ΔS°(system), ΔS°(surroundings), and ΔS°(universe). (Define reactants and products as the system.)

Interpretation Introduction

Interpretation:

It should be identified that whether the given reaction is spontaneous at 298.15K by calculating  ΔS(system), ΔS(surroundings) and ΔS(universe) also the reactants and products should be defined as system.

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.

  ΔS(universe)= ΔS(system)+ΔS(surroundings)

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

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

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

The ΔS(surroundings) can be calculated by the following expression,

  ΔS(surroundings)=ΔrHT

Here, ΔrHo is the enthalpy change for the reaction.

Explanation

Given: Si(s) + 2H2(g)SiH4(g)

The standard entropy of SiH4(g) is 204.65 J/Kmol.

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

The standard entropy of Si(s) is 18.82 J/Kmol.

The standard enthalpy of SiH4(g) is 34.31 kJ/mol.

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

The standard enthalpy of Si(s) is 0 kJ/mol.

The ΔS(universe) for the reaction Si(s) + 2H2(g)SiH4(g) is calculated below.

The balanced chemical equation is:

  Si(s) + 2H2(g)SiH4(g)

Calculation for ΔSo(system):

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

  ΔS(system)=ΔrS°=nS°(products)nS°(reactants)ΔS(system)=[(1 mol SiH4(g)/mol-rxn)S°[SiH4(g)](1 mol Si(s)/mol-rxn)S°[Si(s)]+(2 mol H2(g)/mol-rxn)S°[H2(g)]]

Substituting the respective entropy values,

  ΔS(system)=[(1 mol SiH4(g)/mol-rxn)(204.65 J/Kmol)(1 mol Si(s)/mol-rxn)(18.82 J/Kmol)+(2 mol H2(g)/mol-rxn)(130.7 J/Kmol)]=75

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

A diet book that addresses eicosanoids and adipokines can be relied upon to reflect current scholarship in nutr...

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

Describe the basic elements of bone tissue.

Human Biology (MindTap Course List)

Provide two reasons why meiosis leads to genetic variation in diploid organisms.

Human Heredity: Principles and Issues (MindTap Course List)

Gas is contained in an 8.00-L vessel al a temperature of 20.0C and a pressure of 9.00 atm. (a) Determine the nu...

Physics for Scientists and Engineers, Technology Update (No access codes included)