Relation between Kp and Kc equilibrium: Detailed Explanation with Examples

Kp=Kc(RT)n with R being the gas constant T is the temperature, and N is the change in the number of gaseous moles in the reaction.

Relation between Kp and Kc equilibrium: Detailed Explanation with Examples

Kp=Kc(RT)n with R being the gas constant T is the temperature, and N is the change in the number of gaseous moles in the reaction. Note: Just gaseous moles are considered.

Besides that, what's the relation between KP and KC?

Let's define the relation between Kp and Kc Equilibrium-

The equilibrium constant is Kp in the sense of pressure (pascals). Kc is the equilibrium constant in terms of Molarity (moles/L) R is the optimal gas constant (0.08206 L*atm/mols*K) T = temperature (Kelvin)

In the same way, for what reaction will KP KC? In this instance, you will have two moles of gas on the reaction's side and 5 moles of gas on the reactions' side KpKc. As you have 2 moles of gas on both equilibrium sides, you'll get Kp=Kc.

How can we differentiate KP and KC?

Re: The difference between Kc and Kp is nothing but the equilibrium constant when it's found through the use of concentrations. In contrast, Kp is the equilibrium constant when it's found through using partial pressures.

What is the reason KP and KC aren't the same?

To flip the value of Kc to Kp, we'd need to convert the factor from the molarity (concentration) into the pressure two times in the denominator and 4 times in the denominator since there are molarity units. The conversion factor doesn't match to 1. Therefore Kc isn't equal to Kp in this case.

Let’s have an example-

What’s the relationship between Kp and Kc?

Let’s Consider the following reversible reaction, where:

aA + bB ⇌ cC + dD

We can express equilibrium constant for the reaction expressed as concentration (mol / litre) like this:

K c = [C] c [D] d / [A] a [B] b

If the equilibrium includes gaseous species, the concentrations may be conveyed regarding the gaseous substance’s partial pressures. The equilibrium constant regarding partial pressures may be expressed as:

K p = pcC pdD / paA pbB

Here pA, pB, pC, and pD represent the partial pressures of the A, B, C, and D substances. Assuming the gases to be ideal, then as per the ideal gas equation, it would be:

pV = nRT

p = nRT / V

Where p stands for pressure in Pa

n stands for the amount of gas in mol

V stands for Volume in m3

T stands for temperature in Kelvin

n/V stands for concentration, C


p = CRT or [gas] RT

If C is in mol dm-3 while p is in bar, R will be 0.0831 bar dm3 mol-1 K-1.

Hence, the pressure of the gas P is directly proportional to its concentration C at a constant temperature.

You must deeply analyse the following pic, illustrating an excellent example of the same:

Does KP equal KC?

So Kp=Kc, and if you've got RT to the 0 power, this particular part equals 1. In case you know that delta n equals 0, then Kp equals Kc. In contrast, ensure you use R; 0.08206 and use the temperature in Kelvins. Also, delta n, that you'll use the change in moles of gases.

What is the KC formula?

Kc is any chemical reaction's equilibrium constant. Note down the first chemical reaction equation. This formula, including carbon dioxide, which is CO2, and nitrogen (I) oxide (N2O), is written as CO 2NO=CO2 N2O. Keep in mind this is a homogeneous equilibrium, which means all components are gases.

What is the KC value?

In simple words, the equilibrium constant stands for the value of the reaction quotient that’s computed from the expression for chemical equilibrium.

The equilibrium constant every single time depends on the temperature and ionic strength and is independent of the reactants' concentrations and products in the solution.

What’s the KC expression?

Here’s the prime definition: equilibrium constant expression means the ratio of concentrations of the products and the reactants. The activities of liquids and pure solids are equal to 1.

What does KEQ mean?

Illustrated Glossary of Organic Chemistry - Equilibrium constant or Keq, and Equilibrium constant or Keq, is an actual ratio that quantifies the position of the chemical equilibrium.

What is KP in equilibrium?

Equilibrium constant Kp equals the products’ partial pressure ➗ reactants partial pressure, and the partial pressure is further raised with some power which equals the substance‘s coefficient in the balanced equation.

What is the KC value?

The magnitude of the equilibrium constant indicates the extent to which a particular reaction will proceed. If K is a big number, it indicates that the products’ equilibrium concentration is big. In such a case, the reaction as written proceeds to the right. This results in a definite increase in the products’ concentration.

What are the characteristics of the equilibrium constant?

It has a given value for every single chemical reaction at a given temperature. It’s independent of starting concentrations of the reacting species. Besides that, it will further change as per the change in the temperature. Not just that, it depends on the reaction’s nature.

What do K and Q mean in chemistry?

Equilibrium: Q and K. Let’s consider a simple chemical system that involves just two compounds, A and B: Q stands for the quantity that changes when the reaction system approaches equilibrium. K illustrates the numerical value of Q at the reaction’s closing time when equilibrium is reached.

Is KP only for gases?

Re: Kc, Kp, K

Keep in mind that Kp stands for the equilibrium constant regarding partial pressure, and it can only be used with gases because aqueous solutions don’t have partial pressure. Most importantly, considering homogeneous equilibria, where all the products and reactants are gases, the textbook will consider K and Kp the same.


Let’s conclude by knowing the units of KP and Kc equilibrium now.

On consulting with the Chemistry LibreTexts for the equilibrium constant, you'll locate that every single fo unit of equilibrium constant Kc is mentioned in moles per litre (mol/L).

On the other hand, the equilibrium constant Kp is mentioned in pascals. The formula to calculate the equilibrium constant concerning pressure (pascals) is like Kp = Kc * RT^(n-n0).

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