Combined Gas Law Calculator
Solve for Final Pressure (P2)
Solve for Final Volume (V2)
Solve for Final Temperature (T2)
Formula
(P₁V₁)/T₁ = (P₂V₂)/T₂ | Temperature must be in Kelvin
Frequently Asked Questions
What is the combined gas law?
The combined gas law merges Boyle's, Charles's, and Gay-Lussac's laws into one equation: (P1V1)/T1 = (P2V2)/T2. It relates the pressure, volume, and temperature of a fixed amount of gas between two states.
When do I use the combined gas law vs. the ideal gas law?
Use the combined gas law when comparing the same gas sample under two different sets of conditions (P, V, T). Use the ideal gas law (PV = nRT) when you need to find absolute values or when moles are involved.
What temperature unit must I use?
Always use absolute temperature in Kelvin (K). Convert from Celsius: K = °C + 273.15. Using Celsius or Fahrenheit will give incorrect results.
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