Kp Calculator
Quickly convert equilibrium constants between concentration (Kc) and pressure (Kp) form by applying the ideal gas relationship.
Optional. Defaults to 1 atm.
Kp
0.0004
How to Use This Calculator
Enter Kc
Provide the equilibrium constant expressed in concentration form.
Provide temperature
Use absolute temperature (Kelvin) for the gas constant relationship.
Specify Δn
Calculate the difference in total moles of gaseous products and reactants.
Optional pressure scaling
Include a pressure factor if working at pressures other than 1 atm.
Formula
Kp = Kc (RT)^{Δn}
R = 0.082057 L·atm·mol⁻¹·K⁻¹. When pressure scaling P is used, replace RT with RTP.
Example
With Kc = 1.4, T = 700 K, Δn = −2, Kp = 1.4 × (0.082057 × 700)^-2 ≈ 0.0004.
Full Description
Gas-phase equilibria often use pressure-based constants. The relationship between Kc and Kp depends on temperature and the change in moles of gas. This calculator automates the conversion for quick problem solving.
It assists students and practitioners analyzing chemical equilibria in reactors, environmental systems, or physical chemistry coursework.
Frequently Asked Questions
What is Δn?
It is the moles of gaseous products minus the moles of gaseous reactants in the balanced equation.
Can solids or liquids be included?
Only gases contribute to Δn and Kp expressions. Solids and liquids are excluded.
What if Δn = 0?
Kp = Kc. Temperature and pressure factors cancel out.
Does this handle multiple pressures?
Set the pressure scaling factor to the operating pressure in atm. For varying pressures, adjust accordingly.
Can I convert from Kp to Kc?
Yes. Rearrange the formula: Kc = Kp / (RT)^{Δn}. Enter Kp in the Kc field and invert the expression manually.