The balanced equation for the Haber process can be expressed as:

The Haber process is a widely used method for the large-scale production of ammonia. Named after Fritz Haber, who developed this process in the early 20th century, the equation illustrates the reaction between nitrogen gas ($\text{N}_2$) and hydrogen gas ($\text{H}_2$) to produce ammonia ($\text{NH}_3$).

In this equation, the notation $(g)$ indicates that all reactants and products are in the gaseous state. The double-headed arrow ($\rightleftharpoons$) signifies that the reaction is reversible, meaning it can proceed in both forward and reverse directions. In the forward reaction, nitrogen and hydrogen combine to form ammonia, whereas in the reverse reaction, ammonia breaks down into nitrogen and hydrogen.

The coefficients in front of the chemical formulas are known as stoichiometric coefficients. They represent the proportions in which the reactants combine and the products are formed. According to the balanced equation, one molecule of nitrogen reacts with three molecules of hydrogen to yield two molecules of ammonia.

Balancing the equation is essential as it upholds the law of conservation of mass. This fundamental principle states that matter cannot be created or destroyed during a chemical reaction. In the context of the Haber process, this means that the number of each type of atom is the same on both sides of the equation, ensuring that no atoms are lost or gained throughout the reaction.

In summary, the balanced equation for the Haber process illustrates the reaction of nitrogen and hydrogen to form ammonia, with all substances existing in the gaseous state. The equation is balanced to comply with the law of conservation of mass.