Ch.11 - Liquids, Solids & Intermolecular ForcesWorksheetSee 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: How much energy is released when 42.5 g of water freezes? 

Solution: How much energy is released when 42.5 g of water freezes? 

Problem

How much energy is released when 42.5 g of water freezes?

 

Solution

We’re being asked to calculate the amount of energy released by freezing 42.5 g of water.


Recall that during a phase transition, the temperature is constant

Also note that freezing is an exothermic process, which means q is negative (–).


The amount of energy (q) needed to freeze a given mass is calculated using:


q=m×ΔHfreezing


where:

m = mass (in g)

ΔHfreezing = heat of freezing (in J/g)     *ΔHfreezing = – ΔHfusion


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