Textbook Question
Determine the sign of ΔSsys for each process. a. water boiling
Ch.19 - Free Energy & Thermodynamics
Tro6th EditionChemistry: A Molecular ApproachISBN: 9780137832217
Not the one you use?Change textbookSelect a different textbook
Table of contents
- Ch.1 - Matter, Measurement & Problem Solving118
- Ch.2 - Atoms & Elements106
- Ch.3 - Molecules and Compounds131
- Ch.4 - Chemical Reactions and Chemical Quantities56
- Ch.5 - Introduction to Solutions and Aqueous Solutions82
- Ch.6 - Gases114
- Ch.7 - Thermochemistry96
- Ch.8 - The Quantum-Mechanical Model of the Atom60
- Ch.9 - Periodic Properties of the Elements90
- Ch.10 - Chemical Bonding I: The Lewis Model89
- Ch.11 - Chemical Bonding II: Molecular Shapes, VSEPR & MO Theory85
- Ch.12 - Liquids, Solids & Intermolecular Forces51
- Ch.13 - Solids & Modern Materials47
- Ch.14 - Solutions90
- Ch.15 - Chemical Kinetics115
- Ch.16 - Chemical Equilibrium68
- Ch.17 - Acids and Bases136
- Ch.18 - Aqueous Ionic Equilibrium153
- Ch.19 - Free Energy & Thermodynamics93
- Ch.20 - Electrochemistry106
- Ch.21 - Radioactivity & Nuclear Chemistry74
- Ch.22 - Organic Chemistry140
Chapter 19, Problem 87b
Determine the sign of ΔSsys for each process. b. water freezing
Verified step by step guidance1
Identify the process: Water freezing is a phase change from liquid to solid.
Recall that entropy (ΔS) is a measure of disorder or randomness in a system.
Understand that in the liquid state, water molecules have more freedom of movement compared to the solid state.
Recognize that when water freezes, the molecules become more ordered as they form a crystalline structure.
Conclude that the entropy of the system decreases, so the sign of ΔS_sys is negative.
Verified video answer for a similar problem:
This video solution was recommended by our tutors as helpful for the problem above.
Video duration:
51sWas this helpful?
Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Entropy (ΔS)
Entropy, denoted as ΔS, is a measure of the disorder or randomness in a system. In thermodynamics, a positive ΔS indicates an increase in disorder, while a negative ΔS signifies a decrease in disorder. Understanding how entropy changes during a process is crucial for predicting the spontaneity and feasibility of that process.
Recommended video:
Guided course
02:46
Entropy in Thermodynamics
Phase Changes
Phase changes, such as freezing, involve transitions between solid, liquid, and gas states. During freezing, water transitions from a liquid to a solid state, which typically results in a decrease in entropy because the molecules become more ordered in the solid phase. Recognizing how phase changes affect entropy is essential for analyzing thermodynamic processes.
Recommended video:
Guided course
01:46Entropy in Phase Changes
Second Law of Thermodynamics
The Second Law of Thermodynamics states that the total entropy of an isolated system can never decrease over time. This principle implies that spontaneous processes tend to increase the overall entropy of the universe. When considering processes like water freezing, it is important to evaluate how the entropy of the system and surroundings changes to determine the sign of ΔS.
Recommended video:
Guided course
00:48Second Law of Thermodynamics Example
Related Practice
Textbook Question
Nitrogen dioxide, a pollutant in the atmosphere, can combine with water to form nitric acid. One of the possible reactions is shown here. Calculate ΔG° and Kp for this reaction at 25 °C and comment on the spontaneity of the reaction. 3 NO2(g) + H2O(l)→ 2 HNO3(aq) + NO(g)
Textbook Question
Consider the reaction: 2 NO(g) + O2(g) ⇌ 2 NO2(g) The following data show the equilibrium constant for this reaction measured at several different temperatures. Use the data to find ΔH°rxn and ΔS°rxn for the reaction.
Textbook Question
A reaction has an equilibrium constant of 8.5⨉103 at 298 K. At 755 K, the equilibrium constant is 55.2. Find ΔH°rxn for the reaction.