Ch. 17 - Chemical ThermodynamicsWorksheetSee all chapters
All Chapters
Ch.1 - Intro to General Chemistry
Ch.2 - Atoms & Elements
Ch.3 - Chemical Reactions
BONUS: Lab Techniques and Procedures
BONUS: Mathematical Operations and Functions
Ch.4 - Chemical Quantities & Aqueous Reactions
Ch.5 - Gases
Ch.6 - Thermochemistry
Ch.7 - Quantum Mechanics
Ch.8 - Periodic Properties of the Elements
Ch.9 - Bonding & Molecular Structure
Ch.10 - Molecular Shapes & Valence Bond Theory
Ch.11 - Liquids, Solids & Intermolecular Forces
Ch.12 - Solutions
Ch.13 - Chemical Kinetics
Ch.14 - Chemical Equilibrium
Ch.15 - Acid and Base Equilibrium
Ch.16 - Aqueous Equilibrium
Ch. 17 - Chemical Thermodynamics
Ch.18 - Electrochemistry
Ch.19 - Nuclear Chemistry
Ch.20 - Organic Chemistry
Ch.22 - Chemistry of the Nonmetals
Ch.23 - Transition Metals and Coordination Compounds

Solution: The element gallium (Ga) freezes at 29.8°C, and its molar enthalpy of fusion is ΔH fus = 5.59kJ/mol.1. When molten gallium solidifies to Ga(s) at its normal melting point, is ΔS positive or negative?2

Problem

The element gallium (Ga) freezes at 29.8°C, and its molar enthalpy of fusion is ΔH fus = 5.59kJ/mol.

1. When molten gallium solidifies to Ga(s) at its normal melting point, is ΔS positive or negative?

2. Calculate the value of ΔS when 70.0g of Ga(l) solidifies at 29.8°C. ΔS = ?

Solution

At constant temperature, the change in entropy can be expressed as:

Where: Q = heat , T = Temperature

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