Equilibrium constant writing expressions

The concept of equihbrium constants is extremely important in chemistry. As you will soon see, equihbrium constants are the key to solving a wide variety of stoichiometry problems involving equihbrium systems. For example, an industrial chemist who 

To use equilibrium constants, we must express them in terms of the reactant and product concentrations. Our only guide is the law of mass action [Equation (14.2)], which is the general formula for finding equilibrium concentrations. However, because the concentrations of the reactants and products can be expressed in different units and because the reacting species are not always in the same phase, there may be more than one way to express the equilibrium constant for the same reaction. To begin with, we will consider reactions in which the reactants and products are in the same phase. 

The term homogeneous equilibrium applies to reactions in which all reacting species are in the same phase. An example of homogeneous gas-phase equilibrium is the dissociation of N2O4. The equilibrium constant, as given in Equation (14.1), is 

Note that the subscript in indicates that the concentrations of the reacting species are expressed in molarity or moles per liter. The concentrations of reactants and products in gaseous reactions can also be expressed in terms of their partial pressures. Erom Equation (5.8) we see that at constant tanperature the pressure P of a gas is directly related to the concentration in mol/L of the gas that is, P = (nlV)RT. Thus, for the equilibrium process 

In general, is not equal to Kp, because the partial pressures of reactants and products are not equal to their concentrations expressed in moles per liter. A simple relationship between Kp and K can be derived as follows. Let us consider the following equilibrium in the gas phase  

---

Write equilibrium constant expressions for the following reactions. Determine the value for the equilibrium constant for each reaction using appropriate equilibrium constants from Appendix 3. 

Write equilibrium constant expressions (X) for die following reactions ... 

The concentrations of pure solids and pure liquids are omitted from the equilibrium constant expression because their activity is taken to be 1. Therefore, when writing equilibrium constant expressions, we would omit ... 

Write equilibrium constant expressions (Ksp) for the addition of each of the following substances to water. 

When writing equilibrium constant expressions, use products over reactants. Each concentration is raised to the power of the coefficient in the balanced chemical equation. 

Because the reactions of Br0nsted acids and bases with water are equilibrium reactions, we can write equilibrium constant expressions for these ionizations or dissociations. For example, the dissociation of nitrous acid in water and its equilibrium constant expression are as follows ... 

Write equilibrium constant expressions for the following equations. Tell how they are related. 

Write equilibrium constant expressions for the following equations. Tell how these expressions are related. (a) N2O4 2 NO2 (b) 2 NO2 N2O4 (c) NO2 N2O4... 

A eq for this homogeneous equilibrium at 731 K is 49.7. Note that 49.7 has no units. In writing equilibrium constant expressions, it s customary to omit units. Considering the size of K, are there more products than reactants present at equilibrium ... 

Write equilibrium constant expressions for these equilibria. 

Why should you pay attention to the physical states of all reactants and products when writing equilibrium constant expressions (18.1)... 

Writing Equilibrium-Constant Expressions for Solubility Equilibria. 

Example 16.4 - Writing Equilibrium Constant Expressions for Heterogeneous Equilibria... 

The following examples illustrate the procedure for writing equilibrium constant expressions and calculating equilibrium constants and equilibrium concentrations. 

Write equilibrium constant expressions for and Kp for the formation of nickel tetracarbonyl, which is used to separate nickel from other impurities ... 

SUMAAARY OF GUIDELINES FOR WRITING EQUILIBRIUM CONSTANT EXPRESSIONS... 

Write equilibrium constant expressions for K, and for Kp if applicable, for the following processes ... 

EXAMPLE 2 (a) Write equilibrium constant expressions for equations 1 to 3 below, (b) Determine the relationship of the K value for equation 3 to those of equations 1 and 2. 

We write equilibrium constant expressions for the reactions of weak acids with water, just as we did for regular equilibria, but remember that liquids such as water in dilute solutions are not included in the equilibrium constant expression. The expressions for... 

Write equilibrium-constant expressions and use these expressions to calculate equilibrium constants. 

---