Question

Consider the following chemical reaction:

2CH₂(g) → C₂H₂(g) + 3H₂(g)

Describe what is happening within the system when it is at equilibrium in terms of concentrations, reactions that occur, and reaction rates.​

Answer 1

At equilibrium, the concentrations of reactants and products are constant and do not change over time. In this particular reaction, 2 molecules of CH₂ combine to form 1 molecule of C₂H₂ and 3 molecules of H₂.

Initially, when the reaction starts, there is only CH₂, and as the reaction proceeds, some of the CH₂ molecules are converted into C₂H₂ and H₂. As the concentrations of C₂H₂ and H₂ increase, the reverse reaction can occur where C₂H₂ and H₂ react to form more CH₂ molecules. This process continues until the rate of the forward reaction equals the rate of the reverse reaction, resulting in a state of equilibrium.

At equilibrium, the rate of the forward reaction is equal to the rate of the reverse reaction. The concentrations of reactants and products no longer change over time, and the system is said to be in a state of dynamic equilibrium.