Given kc what is kp

Overview and Key Difference 2. What is Kc 3. What is Kp 4. Relationship Between Kc and Kp 5. Kc is the equilibrium constant given as a ratio between concentrations of products and reactants. The molar concentrations of the components are used for the expression of Kc.

In the expression of Kc, the concentrations of reactants and products are raised to the powers equal to their stoichiometric coefficients. Kp is the equilibrium constant given as a ratio between the pressure of products and reactants. Equilibrium constants are not changed if you change the pressure of the system. The only thing that changes an equilibrium constant is a change of temperature.

That means that if you increase the pressure, the position of equilibrium will move in such a way as to decrease the pressure again — if that is possible. If the gas is one of the reactants or products, this would affect one of the concentrations, and the reaction will have to shift to reestablish equilibrium. Again, this changes one of the rates, but does not affect the rate constants, so Kc is unaffected. The position of equilibrium is changed if you change the concentration of something present in the mixture.

Because there is an equal number of moles on both sides of the reaction, an increase in volume will have no effect on the equilibrium and thus there is no shift in the direction. Similarly, when you decrease the volume there is no effect on the equilibrium.

In the textbook, K refers to Kp, whice is why it always makes a distinction with Kc. In our course reader, however , Kp is explicitly stated. Kc is in terms of molarity and Kp is in terms of pressure. Also both of them are ratios of respective quantities [ ratio of molarity s in Kc and ratio of pressure s in Kp], so they should be dimensionless according to dimensional analysis.

The magnitude of the equilibrium constant, K, indicates the extent to which a reaction will proceed: If K is a large number, it means that the equilibrium concentration of the products is large. If K is a small number, it means that the equilibrium concentration of the reactants is large. The equilibrium constant cannot be 0. This is because this implies that the concentration of products is equal to 0 at equilibrium. The value of the equilibrium constant for any reaction is only determined by experiment.

It does, however, depend on the temperature of the reaction. This is because equilibrium is defined as a condition resulting from the rates of forward and reverse reactions being equal. The true equilibrium constant has no units because they are supposed to be calculated using unitless values called activities. Equilibrium Constant Formula where Kc, indicates the equilibrium constant measured in moles per litre. Since activities are unitless, they eliminate the units of all the quantities in the equilibrium constant expression, making the constant itself unitless all the time.

Thus, they are always in their reference state, and thus always have an activity of 1. Kc and Kp are also dimensionless, as they are defined properly using activities of the reactants and products which are dimensionless too. For simple calculations for Kp, dividing by the standard pressure of 1 bar for each component in the ratio brought to any power will always yield a dimensionless result. Kp is the equilibrium constant calculated from the partial pressures of a reaction equation.

Thus we get the relation between Kp and Kc,. This is the required expression that gives the relation between the two equilibrium constants. The relation between Kp and Kc Pdf can be downloaded. Depending on the change in the number of moles of gas molecules, Kp and Kc relation will be changing.

If the change in the number of moles of gas molecules is positive, i. If the change in the number of moles of gas molecules is negative, i. Consider the following reversible equation and hence calculate Kp and Kc and derive the relationship between Kp and Kc:. Given the reversible equation,.