Consider a system consisting of an ice cube. (a) Under what conditions can the ice cube melt reversibly? (b) If the ice cube melts reversibly, is \(\Delta E\) zero for the process? Explain.

Short Answer

Expert verified
(a) The ice cube can melt reversibly when it is at its melting point (0°C or 273.15 K) and the pressure is constant (at atmospheric pressure). (b) No, ∆E is not zero during a reversible melting process because both heat is absorbed and work is done by the ice cube, indicating that energy is transferred within the system.

Step by step solution

01

(a) Identifying reversible melting conditions

To allow the ice cube to melt reversibly, the melting process must occur under thermodynamic equilibrium. This means: 1. The temperature of the ice cube should be equal to its melting point (0°C or 273.15 K) 2. The pressure applied on the ice cube must be equal to the atmospheric pressure (around 1 atm or 101325 Pa) In conclusion, the ice cube can melt reversibly when it is at its melting point and the pressure is constant (at atmospheric pressure).
02

(b) Determining if ∆E is zero during reversible melting

In order to determine if the change in internal energy (∆E) is zero during a reversible melting process, we can use the first law of thermodynamics, which states: ∆E = Q - W Where: - ∆E is the change in internal energy of the system - Q is the heat added to the system - W is the work done by the system During a constant-pressure reversible melting process, the ice cube absorbs heat (Q) at its melting point, which is used to break the hydrogen bonds within the ice. Simultaneously, the volume of the ice cube changes as the ice transforms into liquid water. This change in volume results in work done by the ice cube (W). Since both heat is absorbed and work is done by the ice cube, it implies that the energy is transferred within the system. Therefore, we can conclude that the change in internal energy (∆E) is NOT zero for the reversible melting process of the ice cube.

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

The value of \(K_{a}\) for nitrous acid \(\left(\mathrm{HNO}_{2}\right)\) at \(25^{\circ} \mathrm{C}\) is given in Appendix D. (a) Write the chemical equation for the equilibrium that corresponds to \(K_{a}\). (b) By using the value of \(K_{a}\), calculate \(\Delta G^{\circ}\) for the dissociation of nitrous acid in aqueous solution. (c) What is the value of \(\Delta G\) at equilibrium? (d) What is the value of \(\Delta G\) when \(\left[\mathrm{H}^{+}\right]=5.0 \times 10^{-2} \mathrm{M}\) \(\left[\mathrm{NO}_{2}^{-}\right]=6.0 \times 10^{-4} \mathrm{M},\) and \(\left[\mathrm{HNO}_{2}\right]=0.20 \mathrm{M} ?\)

In each of the following pairs, which compound would you expect to have the higher standard molar entropy: (a) \(\mathrm{C}_{2} \mathrm{H}_{2}(g)\) or \(\mathrm{C}_{2} \mathrm{H}_{6}(g),(\mathbf{b}) \mathrm{CO}_{2}(g)\) or \(\mathrm{CO}(g) ?\) Explain.

(a) Express the second law of thermodynamics in words. (b) If the entropy of the system increases during a reversible process, what can you say about the entropy change of the surroundings? (c) In a certain spontaneous process the system undergoes an entropy change, \(\Delta S=42 \mathrm{~J} / \mathrm{K} .\) What can you conclude about ?

(a) What do you expect for the sign of \(\Delta S\) in a chemical reaction in which two moles of gaseous reactants are converted to three moles of gaseous products? (b) For which of the processes in Exercise 19.11 does the entropy of the system increase?

Propanol \(\left(\mathrm{C}_{3} \mathrm{H}_{7} \mathrm{OH}\right)\) melts at \(-126.5^{\circ} \mathrm{C}\) and boils at \(97.4{ }^{\circ} \mathrm{C}\). Draw a qualitative sketch of how the entropy changes as propanol vapor at \(150^{\circ} \mathrm{C}\) and 1 atm is cooled to solid propanol at \(-150^{\circ} \mathrm{C}\) and \(1 \mathrm{~atm}\).

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