Warning: foreach() argument must be of type array|object, bool given in /var/www/html/web/app/themes/studypress-core-theme/template-parts/header/mobile-offcanvas.php on line 20

Use the information in Appendix G to estimate the boiling point of CS2.

Short Answer

Expert verified

The estimated boiling point of CS2is 323 K.

Step by step solution

01

Define the enthalpy of the reaction

The change in Gibbs free energy is as follows:

\({\bf{\Delta G = \Delta H - T\Delta S}}\)

where,

\({\bf{\Delta G }}\)= change in Gibbs free energy,

\({\bf{\Delta H}}\)= change in enthalpy,

T = absolute temperature in Kelvin, and

\({\bf{\Delta S}}\)= change in entropy.

The Gibbs free energy change is used to determine the spontaneity of a process. It is expressed in terms of the enthalpy and the entropy of a system.

Entropy is the degree of disorderness or randomness in a given system. The entropy change during a transition phase is expressed as

\({\bf{\Delta S = }}\frac{{{\bf{\Delta H}}}}{{\bf{T}}}\)

02

Determine the estimate the boiling point of CS2

Given:

\({\rm{\Delta }}{{\rm{H}}^ \circ }f({\rm{KJ/mol}})\)

\({{\rm{S}}^ \circ }f({\rm{J/Kmol}})\)

\({\rm{CS2}}\)(g)

115.3

237.8

\({\rm{CS2}}\)(l)

87.3

151

Carbon disulfide vaporization is given by

\({\rm{C}}{{\rm{S}}_{{\rm{2(l)}}}} \to {\rm{C}}{{\rm{S}}_{{\rm{2(g)}}}}\)

Solve for enthalpy change of vaporization

\(\Delta {H_{vap}} = \Delta H_{f\left( {C{S_{2(g)}}} \right.}^o - \Delta H_{f\left( {C{S_{2(l)}}} \right.}^o = 115.3 - 87.3 = 28\frac{{kJ}}{{ mole }}\)

Solve for entropy change of vaporization

\({\rm{\Delta }}{{\rm{S}}_{{\rm{vap}}}}{\rm{ = \Delta S}}_{{\rm{f}}\left( {{\rm{C}}{{\rm{S}}_{{\rm{2(g)}}}}} \right.}^{\rm{o}}{\rm{ - \Delta S}}_{{\rm{f}}\left( {{\rm{C}}{{\rm{S}}_{{\rm{2(l)}}}}} \right.}^{\rm{o}}{\rm{ = 237}}{\rm{.8 - 151 = 86}}{\rm{.8}}\frac{{\rm{J}}}{{{\rm{ mole \times K}}}}\)

Solve boiling point using entropy definition for phase changes

\(\Delta {S_{vap}} = \frac{{\Delta {H_{vap}}}}{{{T_b}}}\)

\(\begin{array}{l}{{\rm{T}}_{\rm{b}}}{\rm{ = }}\frac{{{\rm{\Delta }}{{\rm{H}}_{{\rm{vap}}}}}}{{{\rm{\Delta }}{{\rm{S}}_{{\rm{vap}}}}}}\\{\rm{ = }}\frac{{{\rm{28000}}\frac{{\rm{J}}}{{{\rm{ mole }}}}}}{{{\rm{86}}{\rm{.8}}\frac{{\rm{J}}}{{{\rm{ mole \times K}}}}}}\\{\rm{ = 323K}}\end{array}\)

Unlock Step-by-Step Solutions & Ace Your Exams!

  • Full Textbook Solutions

    Get detailed explanations and key concepts

  • Unlimited Al creation

    Al flashcards, explanations, exams and more...

  • Ads-free access

    To over 500 millions flashcards

  • Money-back guarantee

    We refund you if you fail your exam.

Over 30 million students worldwide already upgrade their learning with Vaia!

One App. One Place for Learning.

All the tools & learning materials you need for study success - in one app.

Get started for free

Most popular questions from this chapter

Calculate ฮ”Gยฐ using

(a) free energies of formation and

(b) enthalpies of formation and entropies(Appendix G). Do the results indicate the reaction to be spontaneous or nonspontaneous at 25 ยฐC?

\({{\bf{C}}_{\bf{2}}}{{\bf{H}}_{\bf{4}}}{\bf{(g)}} \to {{\bf{H}}_{\bf{2}}}{\bf{(g) + }}{{\bf{C}}_{\bf{2}}}{{\bf{H}}_{\bf{4}}}{\bf{(g)}}\)

In the laboratory, hydrogen chloride \({\bf{(HCl(g))}}\) and ammonia \(\left( {{\bf{N}}{{\bf{H}}_{\bf{3}}}{\bf{(g)}}} \right)\)often escape from bottles of their solutions and react to form the ammonium chloride\(\left( {{\bf{N}}{{\bf{H}}_{\bf{4}}}{\bf{Cl(s)}}} \right)\), the white glaze often seen on glassware. Assuming that the number of moles of each gas that escapes into the room is the same, what is the maximum partial pressure of \({\bf{HCl}}\) and \({\bf{N}}{{\bf{H}}_{\bf{3}}}\)in the laboratory at room temperature? (Hint: The partial pressures will be equal and are at their maximum value when at equilibrium.)

An important source of copper is from the copper ore, chalcocite, a form of copper(I) sulfide. When heated, the \({\bf{C}}{{\bf{u}}_{\bf{2}}}{\bf{S}}\) decomposes to form copper and sulfur described by the following equation:

\({\bf{C}}{{\bf{u}}_{\bf{2}}}{\bf{\;S(s)}} \to {\bf{Cu(s) + S(s)}}\)

(a) Determine \({\bf{\Delta G}}_{{\bf{298}}}^{\bf{^\circ }}\)for the decomposition of \({\bf{C}}{{\bf{u}}_{\bf{2}}}{\bf{S(\;s)}}\).

(b) The reaction of sulfur with oxygen yields sulfur dioxide as the only product. Write an equation that describes this reaction, and determine\({\bf{\Delta G}}_{{\bf{298}}}^{\bf{^\circ }}\)for the process.

(c) The production of copper from chalcocite is performed by roasting the \({\bf{C}}{{\bf{u}}_{\bf{2}}}{\bf{S}}\) in air to produce the \({\bf{Cu}}\). By combining the equations from Parts (a) and (b), write the equation that describes the roasting of the chalcocite, and explain why coupling these reactions together makes for a more efficient process for the production of the copper.

Predict the sign of the enthalpy change for the following processes. Give a reason for your prediction.

(a) \({\bf{NaN}}{{\bf{O}}_{\bf{3}}}{\bf{(s)}} \to {\bf{N}}{{\bf{a}}^{\bf{ + }}}{\bf{(aq) + N}}{{\bf{O}}_{\bf{3}}}^{\bf{ - }}{\bf{(aq)}}\)

(b) the freezing of liquid water

(c) \({\bf{C}}{{\bf{O}}_{\bf{2}}}{\bf{(s)}} \to {\bf{C}}{{\bf{O}}_{\bf{2}}}{\bf{(g)}}\)

(d) \({\bf{CaCO(s)}} \to {\bf{CaO(s) + C}}{{\bf{O}}_{\bf{2}}}{\bf{(g)}}\)

Write conversion factors (as ratios) for the number of:

(a) yards in 1 meter

(b) liters in 1 liquid quart

(c) pounds in 1 kilogram

See all solutions

Recommended explanations on Chemistry Textbooks

View all explanations

What do you think about this solution?

We value your feedback to improve our textbook solutions.

Study anywhere. Anytime. Across all devices.

Sign-up for free