Convert Kc to Kp

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Equation / Last modified by KurtHeckman on 2017/10/12 19:40
`K_p = `
Convert Kc to Kp
Variable Instructions Datatype
`(K_c)"Equilibrium constantant calculated from concentrations"` Enter the equilibrium constant. Decimal (mol/L)
`(T)"Temperature"` T is the temperature in Kelvin (K) Decimal (K)
`(n)"Number of moles of products"` n is the number of moles of products (disregarding solids and liquids) Decimal (mol)
`(n_0)"Number of moles of reactants"` N is the number of moles of reactants (disregarding solids and liquids) Decimal (mol)
Type
Equation
Category
vCommons
Contents
4 variables
Rating
ID
ekskekel.Convert Kc to Kp
UUID
c716d20f-1dee-11e6-9770-bc764e2038f2

The Conversion of Kc to Kp calculator uses the formula Kp = Kc * RT(n-n0) to compute an equilibrium constant in terms of pressure by using an equilibrium constant in terms of molarity. 

INSTRUCTIONS: Choose your preferred units and enter the following:

  • (Kc) Equilibrium constant in terms of molarity (mols/L)
  • (T) Temperature 
  • (n) Number of moles of products in the gas phase
  • (n0) Number of moles of reactants in the gas phase

Kp:  The calculator makes all of the needed unit conversions and returns the equilibrium constant (Kp) in kilo-pascals.  However, this can be automatically converted to other pressure units via the pull-down menu.

Related Items:

  • Relationship between temperature and volume, Charles Law Calculator:
    • `V_1``T_2` = `V_2``T_1`
  • Relationship between pressure and volume: Boyles Law Calculator
    •  `P_1``V_1` = `P_2``V_2`
  • Relationship between temperature and pressure, Gay-Lussac Law:
    • `T_1``P_2`=`T_2``P_1`
  • Relationship between temperature, volume and pressure, Combined Gas Law Calculator:
    •  PV / T = k
  • Relationship between pressure, volume, moles and temperature, Ideal Gas Law:
    • PV = n•R•T

The Science

Note: in this formula, only gaseous substances are taken in to consideration. Aqueous species are taken into account when calculating other equilibrium constants, but this equation focuses specifically on gaseous species with partial pressures.

Equilibrium constants can be used to predict the direction that a reaction will proceed, and is useful in chemistry, biology, and biochemistry. When K > 1, equilibrium favors the products, and when K < 1, equilibrium favors the reactants.

The Math

The formula used in this calculator is as follows:

            Kp = Kc * RT(n-n0)

where: 

  • Kc = equilibrium constant in terms of molarity (mols/L)
  • R = ideal gas constant (0.08206 L*atm/mols*K)
  • T = temperature (Kelvin)
  • n = number of moles of products in the gas phase
  • n0 = number of moles of reactants in the gas phase

References

Whitten, et al. "Chemistry" 10th Edition. Pp. 734

ChemWiki

See Also

Acid Equilibrium Constant (Ka)

Base Equilibrium Constant (Kb)

 

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