Gas Laws Calculator & Table
The ultimate reference for Gas Laws. Instantly solve for any missing variable using the Universal Gas Law Calculator.
Universal Gas Law Calculator
Solve for any missing variable instantly.
Boyle's Law
Pressure is inversely proportional to volume at constant temperature.
Charles's Law
Volume is directly proportional to temperature (in Kelvin) at constant pressure.
Gay-Lussac's Law
Pressure is directly proportional to temperature (in Kelvin) at constant volume.
Avogadro's Law
Volume is directly proportional to the amount of gas (moles) at constant T and P.
Ideal Gas Law
The equation of state relating all four variables for a hypothetical ideal gas.
Combined Gas Law
Combines Boyle's, Charles's, and Gay-Lussac's laws into one expression.
Dalton's Law
The total pressure of a gas mixture is the sum of the partial pressures of each component.
Graham's Law
The rate of effusion of a gas is inversely proportional to the square root of its molar mass.
Henry's Law
The solubility of a gas in a liquid is directly proportional to the partial pressure of that gas above the liquid.
Kinetic Molecular Theory (KMT)
The Kinetic Molecular Theory explains why gases behave the way they do (as described by Boyle, Charles, etc.). It assumes that gas particles are in constant, random motion and that collisions between particles and the container walls are perfectly elastic.
Gases consist of large numbers of tiny particles.
Particles are in continuous, rapid, random motion.
No kinetic energy is lost during collisions.
There are no attractive or repulsive forces between particles.
Gas Laws in Real Life
Breathing (Boyle's Law)
When your diaphragm contracts (moves down), your lung volume increases. This decreases pressure inside the lungs, causing air to rush in to equalize it.
Tires in Winter (Gay-Lussac)
When the outside temperature drops properly, the air molecules inside your tires move slower. This decreases pressure, often triggering your car's TPM sensor.
Hot Air Balloons (Charles's)
Heating the air inside the balloon increases its volume (and decreases density). The hotter, less dense air rises above the cooler, denser air outside.
Tips for solving Gas Law Problems
- Always use Kelvin: Temperature must be in Kelvin. $K = ^\circ C + 273$.
- Consistency is Key: For laws like Boyle's ($P_1V_1 = P_2V_2$), units for Pressure and Volume must match on both sides (e.g., both atm, or both kPa).
- Visualize variables: Identify what is changing. If Temperature is constant, you typically need Boyle's Law. If Pressure is constant, Charles's Law.
Frequently Asked Questions
What is the Ideal Gas Law formula?
The Ideal Gas Law is PV = nRT, where P is pressure (atm), V is volume (L), n is the number of moles, R is the ideal gas constant (0.0821 L⋅atm/mol⋅K), and T is temperature (Kelvin).
How do I convert Celsius to Kelvin?
To convert Celsius to Kelvin, add 273.15 to the Celsius temperature. For example, 25°C + 273.15 = 298.15 K. Gas laws ALWAYS use Kelvin.
What does Boyle's Law state?
Boyle's Law (P₁V₁ = P₂V₂) states that pressure and volume are inversely proportional at constant temperature. As volume decreases, pressure increases.
What separates an Ideal Gas from a Real Gas?
An Ideal Gas assumes particles have no volume and no intermolecular forces. Real gases deviate from this behavior at high pressures and low temperatures.
What is Charles's Law?
Charles's Law (V₁/T₁ = V₂/T₂) states that volume is directly proportional to temperature at constant pressure. As a gas heats up, it expands.
What is the Combined Gas Law?
The Combined Gas Law combines Boyle's, Charles's, and Gay-Lussac's laws into one equation: P₁V₁/T₁ = P₂V₂/T₂. It is used when P, V, and T all change.
What is STP in chemistry?
STP stands for Standard Temperature and Pressure. It is defined as 0°C (273.15 K) and 1 atmosphere (1 atm) of pressure. At STP, 1 mole of gas occupies 22.4 liters.
What is Gay-Lussac's Law?
Gay-Lussac's Law (P₁/T₁ = P₂/T₂) states that pressure is directly proportional to temperature at constant volume. This explains why tire pressure drops in winter.
What is Dalton's Law of Partial Pressures?
Dalton's Law states that the total pressure of a gas mixture is the sum of the partial pressures of each individual gas component (P_total = P₁ + P₂ + ...).
Who formulated Avogadro's Law?
Amedeo Avogadro formulated the law stating that equal volumes of gases at the same temperature and pressure contain equal numbers of molecules (V ∝ n).