Question

Define reversible and irreversible reactions. Give examples.

Short answer

Answer: The main difference between reversible and irreversible reactions is that reversible reactions can be reversed by changing the conditions to convert the products back into the reactants, while irreversible reactions go to completion and cannot be reversed by simply changing the conditions. An example of a reversible reaction is the synthesis and decomposition of ammonia (N2(g) + 3H2(g) ⇌ 2NH3(g)). An example of an irreversible reaction is the combustion of methane (CH4(g) + 2O2(g) → CO2(g) + 2H2O(g)).

Step-by-step solution

Definition of Reversible Reaction

A reversible reaction is a chemical reaction that, once complete, can be reversed by changing the conditions to convert the products back into the reactants. Reversible reactions can reach a state of equilibrium, where both the forward and reverse reactions occur at the same rate.

Example of Reversible Reaction

An example of a reversible reaction is the synthesis and decomposition of ammonia. When nitrogen gas (N2) reacts with hydrogen gas (H2) to form ammonia (NH3), it can also decompose back into nitrogen and hydrogen when the conditions are changed. The reaction can be represented as follows: N2(g) + 3H2(g) ⇌ 2NH3(g)

Definition of Irreversible Reaction

An irreversible reaction is a chemical reaction that goes to completion, meaning it proceeds in the forward direction only, with no significant chance of the products converting back into the reactants. Once the reaction is completed, it cannot be reversed by simply changing the conditions.

Example of Irreversible Reaction

An example of an irreversible reaction is the combustion of a hydrocarbon, such as methane burning in the presence of oxygen to produce carbon dioxide and water. Once the reaction has occurred, it cannot be simply reversed to form methane and oxygen again. The reaction can be represented as follows: CH4(g) + 2O2(g) → CO2(g) + 2H2O(g)