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
Jules Bruno

Charles’ Law, also known as the Law of Volumes, is a simple gas law that helps to explain what happens to the volume of a dry gas as it is heated. 

Charles’ Law

Charles’ Law, named after the balloonist Jaques Charles, was theorized in order to examine the compressibility of gases. According to the findings of Charles, at constant pressure and amount for a gas, the volume (V) and absolute temperature (T) are directly proportional. 

Thermal Expansion

The direct temperature-volume relationship with Charles’ Law can be illustrated by the following example: 

Thermal-Expansion-Balloon-expandThermal Expansion of a ballon (Charles Law Application)

As the temperature from the hotplate is increased (290 K to 360 K), the gas molecules will absorb the additional thermal energy and convert it to kinetic energy. This causes the gas molecules to move faster and collide with the borders of the balloon with greater force. As a result of this increasing temperature, the volume inside the balloon also increases. 


Temperature-Volume Plot

The linear relationship between temperature and volume can be plotted as the following graph: 

Temperature-Volume-Plot-Graph-DefinitionCharles Law Graph Representation (VT Plot)

At constant pressure (P) and moles (n), this linear relationship between temperature (T) and volume (V) produces the following expression: 

Temperature-Volume-ExpressionTemperature-Volume Expression

Charles’ Law Formula

Isolating the variables of volume (V) and absolute temperature (T) can be accomplished by rearranging the Ideal Gas Law:

Charles-Law-DerivationDerivation of Charles' Law

When moles (n) and pressure (P) are in fixed states then the right side of the equation simplifies to: 

Temperature-Volume-Ratio-k-assumes-constant-charles-lawTemperature-Volume Ratio & k constant (Charles' Law)

When dealing with 2 Volumes (V1 and V2) and 2 Tempertaures (T1 and T2) we obtain Charles’ Law Formula: 

Charles-Law-Formula-EquationCharles' Law Formula


PRACTICE: A hot air balloon is filled with 1.33 x 106 L of an ideal gas on a cool morning (11°C) at 1.01 atm. The volume in the hot air balloon expands to 3.05 x 106 L. What is the temperature of the air in the balloon after its expansion? Assume that none of the gas escapes from the balloon and the conditions are isobaric.


STEP 1: Identify the variables that have changed and ignore the variables that have remained constant because they will not affect the final answer. 

Charles-Law-V1-T1-V2-T2-variables-examples-calculator-worksheetCharles' Law (Identifying Variables)

STEP 2: Kinetic Molecular Theory states that all calculations dealing with temperature have to be done under absolute temperature. This means we must convert Celsius into Kelvin. 

Absolute-Temperature-conversionAbsolute Temperature (Charles' Law)

STEP 3: Plug the given values into the Charles’ Law formula.

Charles-Law-Solving-for-T2Charles' Law (V1/T1 = V2/T2)

STEP 4: Perform cross-multiplication between the two ratios. 

Charles-Law-Cross-MultiplicationCharles' Law (Cross Multiplication)

STEP 5: Isolate the missing variable for the second temperature (T2). 

Charles-law-isolating-variable-V1-T1-V2-T2Charles' Law (V1T2 = V2T1)

The Other Gas Law Equations

Charles’ Law represents one of the Simple Gas Laws in chemistry and like the others it tries to explain the reactive behavior of gases under varying conditions of pressure, volume, temperature or amount. The other Simple Gas Laws include Boyle’s Law, Avogadro’s Law and Gay-Lussac’s Law. Together these different laws combine to form the Ideal Gas Law when discussing ideal gases. 


Jules Bruno

Jules felt a void in his life after his English degree from Duke, so he started tutoring in 2007 and got a B.S. in Chemistry from FIU. He’s exceptionally skilled at making concepts dead simple and helping students in covalent bonds of knowledge.