Charles's Law Calculator

Calculate gas volume and temperature relationships at constant pressure

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V₁/T₁ = V₂/T₂

Volume and Temperature are directly proportional at constant pressure

Step-by-Step Solution

Visual Representation

V₁

T₁ =

Heat/Cool
V₂

T₂ =

Related Gas Laws Reference

Law Name Formula Relationship

Temperature Conversion Reference

Celsius → Kelvin

K = °C + 273.15

Fahrenheit → Kelvin

K = (°F - 32) × 5/9 + 273.15

Kelvin → Celsius

°C = K - 273.15

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About Charles's Law Calculator

What is Charles's Law?

Charles's Law is one of the fundamental gas laws in chemistry and physics that describes the relationship between the volume and temperature of a gas when the pressure and amount of gas remain constant. Named after French scientist Jacques Charles, it states that the volume of a given mass of gas is directly proportional to its absolute temperature.

The Charles's Law Formula

The mathematical expression for Charles's Law is:

V₁/T₁ = V₂/T₂

Where:

  • V₁ = Initial volume of the gas
  • T₁ = Initial absolute temperature (in Kelvin)
  • V₂ = Final volume of the gas
  • T₂ = Final absolute temperature (in Kelvin)

How to Use This Calculator

  1. Select what to solve for: Choose whether you want to find V₁, T₁, V₂, or T₂
  2. Enter the known values: Input the three known values
  3. Select temperature units: Choose Kelvin, Celsius, or Fahrenheit
  4. View results: Get instant results with step-by-step explanation

Important Temperature Conversions

  • Celsius to Kelvin: K = °C + 273.15
  • Fahrenheit to Kelvin: K = (°F - 32) × 5/9 + 273.15
  • Kelvin to Celsius: °C = K - 273.15

Critical Note: Charles's Law requires temperatures in Kelvin. Never use Celsius or Fahrenheit directly in the formula.

Example Calculation

A gas occupies 2.5 liters at 25°C. What will its volume be at 50°C?

  1. Convert temperatures to Kelvin:

    • T₁ = 25 + 273.15 = 298.15 K
    • T₂ = 50 + 273.15 = 323.15 K
  2. Apply Charles's Law:

    • V₂ = V₁ × (T₂/T₁)
    • V₂ = 2.5 × (323.15/298.15)
    • V₂ = 2.71 L

Real-World Applications

  • Hot air balloons: The air inside heats up, expands, and becomes less dense
  • Tire pressure: Tires expand in hot weather and contract in cold
  • Aerosol cans: Warning labels about not exposing to heat
  • Weather balloons: Expand as they rise into colder atmosphere
  • Engine cylinders: Gas expansion in combustion engines

Related Gas Laws

  • Boyle's Law: P₁V₁ = P₂V₂ (pressure-volume relationship)
  • Gay-Lussac's Law: P₁/T₁ = P₂/T₂ (pressure-temperature relationship)
  • Ideal Gas Law: PV = nRT (combines all gas laws)

Limitations

  • Only applies to ideal gases
  • Pressure must remain constant
  • Amount of gas must remain constant
  • Temperature must be in absolute scale (Kelvin)
  • Real gases deviate at high pressures or low temperatures

Frequently Asked Questions

Why must temperature be in Kelvin?

Charles's Law shows direct proportionality. At 0°C, gases don't have zero volume—Kelvin represents true absolute zero where molecular motion stops.

What happens at absolute zero?

Theoretically, gas volume would be zero. However, all gases condense to liquids before reaching absolute zero.

Does Charles's Law work for all gases?

It works well for ideal gases and reasonably well for real gases at moderate temperatures and pressures.