Chemical Equilibrium

Chemical equilibrium is usually defined as a state in which the rate of the forward reaction is equal to the rate of the backward reaction. In other words, we can also say that the concentration of the reactant and the concentration of the products do not change with time. Chemical equilibrium occurs when a reversible reaction is occurring backward and forwards at the same time by the same amount, and one can say that when the rates are equal, equilibrium has occurred. The reaction then appears to have stopped, and the total amount of products and reactants remain stable.

Types of chemical equilibrium

Homogeneous equilibrium

A homogeneous equilibrium is one in which all of the reactants and products are present in a single solution, the reactions between solutes in liquid solutions belong to one type of homogeneous equilibria. The chemical species involved can be molecules, ions, or a mixture.

Heterogeneous equilibrium

A heterogeneous equilibrium is a system in which reactants and products are found in two or more phases. The phases may be any combination of solid, liquid, or gas phases, and solutions, the solids, and pure liquids do not appear in equilibrium constant expressions.

A reaction is in chemical equilibrium when the rate of the forward reaction equals the rate of the reverse reaction. There are numerous examples of chemical equilibrium; one such example is a bottle of fizzy cold drink, in that bottle, there is carbon dioxide which is dissolved in the liquid. To know more about the chemical equilibrium of the reactions we could refer to Le Chatelier’s principle, it is an observation about the chemical equilibrium of reactions. It states that changes in the temperature, pressure, volume, or concentration of a system will result in the system opposing the change to achieve a new equilibrium state, equilibrium is categorized into three types and these are stable, unstable, and neutral. The temperature, pressure, and concentration of the system are all the factors that affect equilibrium. When one of these factors changes, the equilibrium of the system is disrupted, and the system changes or readjusts itself until it returns to an equilibrium state. The term chemical equilibrium is used to describe a chemical reaction in which the concentrations of the substances involved remain constant and 

The main characteristics of chemical equilibrium are:

• (The reaction rates) the rates of forwarding and reverse reactions are equal.
• All the reactants and products are present at equilibrium.
• The position of equilibrium is not affected by a catalyst.

When a system has reached equilibrium, no further changes in the reactant and product concentrations occur; the reactions continue to occur, but at equivalent rates, also the concept of equilibrium does not imply equal concentrations. When all the forces that act upon an object are balanced or cancel out each other, then the object is said to be in a state of equilibrium. Objects at equilibrium must have an acceleration of 0 m/s/s. and this extends from Newton’s first law of motion. The increasing temperature always shifts the chemical equilibrium in the direction of the endothermic reaction. Changing the pressure also affects equilibrium. For example, decreasing the volume of a gas system increases its pressure, which increases the concentration of both reactants and products and if the concentration of a substance is changed, the equilibrium will shift to minimize the effect of that change, to nullify the effect, If the concentration of a reactant has increased the equilibrium will shift in the direction of the reaction that uses the reactants so that the reactant concentration decreases. 

Conclusion

The chemical equilibrium is a state in which the rate of the forward reaction is equal to the rate of the reverse reaction, there is no net change in the concentrations of reactants and products and this does not mean that all chemical reaction has ceased. When equilibrium reactions are disrupted, such as the binding of oxygen by haemoglobin, as in carbon monoxide poisoning, it can be life-threatening. Conversely, controlling an equilibrium reaction is also very important in chemical manufacturing, like in the synthesis of ammonia.