# Is the reaction Si(s) + 2 Cl 2 (g) → SiCl 4 (g) spontaneous under standard conditions at 298.15 K? Answer this question by calculating Δ S °(system), Δ S °(surroundings), and Δ S °(universe). (Define reactants and products as the system.)

### Chemistry & Chemical Reactivity

9th Edition
John C. Kotz + 3 others
Publisher: Cengage Learning
ISBN: 9781133949640

Chapter
Section

### Chemistry & Chemical Reactivity

9th Edition
John C. Kotz + 3 others
Publisher: Cengage Learning
ISBN: 9781133949640
Chapter 18, Problem 9PS
Textbook Problem
57 views

## Is the reaction Si(s) + 2 Cl2(g) → SiCl4(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 of Solution

Given: Si(s) + 2Cl2(g)SiCl4(g)

The standard entropy of SiCl4(g) is 330.86 J/Kmol.

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

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

The standard enthalpy of SiCl4(g) is 662.75 kJ/mol.

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

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

The ΔS(universe) for the reaction Si(s) + 2Cl2(g)SiCl4(g) is calculated below.

The balanced chemical equation is:

Si(s) + 2Cl2(g)SiCl4(g)

Calculation for ΔSo(system):

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

ΔS(system)=ΔrS°=nS°(products)nS°(reactants)=[(1 mol SiCl4(g)/mol-rxn)S°[SiCl4(g)](1 mol Si(s)/mol-rxn)S°[Si(s)]+(2 mol Cl2(g)/mol-rxn)S°[Cl2(g)]]

Substituting the above entropy values results to yield the entropy of the system.

ΔS(system)=[(1 mol SiCl4(g)/mol-rxn)(330.86 J/Kmol)(1 mol Si(s)/mol-rxn)(18.82 J/Kmol)+(2 mol Cl2(g)/mol-rxn)(223.08 J/Kmol)]=134

### 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

#### Additional Science Textbook Solutions

Find more solutions based on key concepts
Contrast the three main clades of mammals.

Biology (MindTap Course List)

Bacteria, Archaea, and Eukarya are three ________.

Biology: The Unity and Diversity of Life (MindTap Course List)

The bodys use of fat for fuel without the help of carbohydrate results in the production of a. ketone bodies b....

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

What are the two fuels for the urea cycle?

Organic And Biological Chemistry

A light rope passes over a light, frictionless pulley. One end is fastened to a bunch of bananas of mass M, and...

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

Use the definition of Avogadros number to find the mass of a helium atom.

Physics for Scientists and Engineers with Modern Physics

How does sand move on a beach?

Oceanography: An Invitation To Marine Science, Loose-leaf Versin