Explain why it is necessary to balance chemical equations in terms of maintaining equilibrium. How can you tell when a chemical reaction has reached equilibrium? Give an example to help explain your answer.

See explanation.

Explanation:

Hello,

In this case, we say that chemical reactions are governed by the law of conservation of mass, which states that matter cannot be neither created nor destroyed by transformed, for that reason, we need to balance chemical reactions in order to ensure all the atoms to be in the same quantity at both reactants and products.

Moreover, equilibrium is defined as such condition at which the concentration of both reactants and products stop changing over the time so they become constant as well as their null reaction rate.

A widely acknowledged reaction is the HABER one which consists on the synthesis of ammonia by using elemental nitrogen and hydrogen:

In such reaction, we have two nitrogens at both reatants and products and six hydrogens at at both reatants and products for us to obey the law of conservation of mass. Furthermore, as the time goes by, nitrogen reacts with hydrogen, nonetheless, they do not react indefinitely, they have a limit that is equilibrium, so their moles stop being consumed and remain unchanged as well as the produced moles of ammonia.

Best regards.