Question

When a chemical system is at equilibrium, A. the concentrations of the reactants are equal to the concentrations of the products. B. the concentrations of the reactants and products have reached constant values. C. the forward and reverse reactions have stopped. D. the reaction quotient, Picture, has reached a maximum. E. the reaction quotient, Picture, has reached a minimum.

Answer 1

Answer: The correct option is option B (the concentrations of the reactants and products have reached constant values).

Explanation:

CHEMICAL EQUILIBRIUM is defined as a state which is attained in a chemical system where by forward reaction occurs at the same rate with the backward reaction leading to CONSTANT CONCENTRATIONS of the reactants and the products. Chemical equilibrium is achievable in a closed Chemical system so that none of the reactants or products would escape be they gaseous or otherwise.

Chemical equilibrium occurs in a type of reaction called reversible reactions. Reversible reactions is one that can go in either direction depending on the condition of the system. In other words, reactants form products and under favourable conditions products react together to reform the reactants. For example,

3Fe(s) + 4H2O(l) <-------> Fe3O4(s) + 4H2(g)

As the above reversible reaction proceeds, a time is reached when the rate of forward reaction { which is the formation of Fe3O4(s) + 4H2(g)} is equal to the rate of the backward reaction {which is the formation of 3Fe(s) + 4H2O(l)}. At this point, concentrations of the reactants and products have reached constant values.