Which of the following can we predict from an equilibrium constant for a reaction?
1 The extent of a reaction
2 Whether the reaction is fast or slow
3 Whether a reaction is exothermic or endothermic
a. 1 only
b. 2 only
c. 3 only
d. 1 and 2 only
e. 1 and 3 only
The answers is a. We can only predict the extent of a chemical reaction and the direction of a reaction from the
Keq
To determine the correct answer, let's break down the question:
The equilibrium constant (K) is a numerical value that represents the ratio of product concentrations to reactant concentrations at equilibrium for a chemical reaction. It is determined based on the stoichiometry of the reaction and the concentrations of the species involved.
Now, let's evaluate each statement:
1. The extent of a reaction: Yes, the equilibrium constant can provide information about the extent of a reaction. A higher value of K indicates that the equilibrium lies more towards the product side, suggesting a greater extent of reaction in favor of products.
2. Whether the reaction is fast or slow: No, the equilibrium constant does not provide any information about the speed of a reaction. Reaction rate, which relates to the speed of a reaction, is not determined by the equilibrium constant.
3. Whether a reaction is exothermic or endothermic: No, the equilibrium constant does not provide information about the energy changes (exothermic or endothermic) that occur during a reaction. The equilibrium constant only reveals the relative concentrations of products and reactants at equilibrium.
Based on the evaluation, the correct answer is:
a. 1 only
The extent of a reaction can be predicted from an equilibrium constant, but the speed and energy changes cannot be determined solely from the equilibrium constant.
The correct answer is e. 1 and 3 only.
The equilibrium constant for a reaction provides information about the extent of the reaction and whether it is exothermic or endothermic. It does not provide information about the rate of the reaction, which is related to whether the reaction is fast or slow.