“Exploring Homogeneous and Heterogeneous Equilibrium in Chemical Reactions”

 

“Exploring Homogeneous and Heterogeneous Equilibrium in Chemical Reactions”

Introduction:

Chemical equilibrium is a pivotal concept in the realm of chemistry, describing the balance between reactants and products in a reaction. This equilibrium can be further classified into two main types:

• Homogeneous equilibrium
• Heterogeneous equilibrium

In this article, we will delve into the distinctions between these two types of equilibrium, provide real-world examples, and discuss the relationship between homogeneous equilibrium and the Law of Mass Action, all within the context of chemical equilibrium and equilibrium constants.

Homogeneous Equilibrium:

Homogeneous equilibrium occurs when all the reactants and products are in the same phase, typically in a gaseous or liquid state. This means that the concentrations are expressed in terms of molar concentrations (in the case of gases) or molarity (in the case of liquids). The equilibrium constant, denoted as K_c, is a fundamental parameter used to quantify homogeneous equilibrium.

Example:

Consider the reaction of nitrogen dioxide (NO₂) with dinitrogen tetroxide (N₂O₄), both in the gas phase.

N₂O₄(g) ⇌ 2NO₂(g)

The K_c for this reaction is mentioned below:

Kc = [NO₂]² / [N₂O₄]

Heterogeneous Equilibrium:

Heterogeneous equilibrium, on the other hand, involves reactants and products in different phases, such as a solid and a gas or a liquid and a gas. In such cases, the concentration of solids or pure liquids is considered constant, and only the concentrations of gases are taken into account when determining the equilibrium constant. The equilibrium constant is represented as K_c or K_p, depending on the concentrations or partial pressures of the gaseous species.

Example:

The decomposition of calcium carbonate (CaCO₃) into calcium oxide (CaO) and carbon dioxide (CO₂) in the solid and gas phases:

CaCO₃(s) ⇌ CaO(s) + CO₂(g)

The equilibrium constant is expressed as:

K_c = [CO₂][ CaO] / [CaCO₃]