AP Chemistry Flashcards: Calculating the Equilibrium Constant
Written by AP Content Team, Verified for 2026 AP Exams, Last updated: May 2026
Review key ideas with interactive flashcards. This set includes 10 cards to help you master important concepts.
What is the basis for calculating the equilibrium constant, Kc?
Kc is calculated based on the experimental measurements of the concentrations of reactants and products once the reaction has reached equilibrium.
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What is the basis for calculating the equilibrium constant, Kc?
Kc is calculated based on the experimental measurements of the concentrations of reactants and products once the reaction has reached equilibrium.
A student measures the pressures of gases in a reaction mixture and finds they are no longer changing. Why is this observation important for calculating Kp?
This observation indicates the system has reached equilibrium, which is the required state for the measured partial pressures to be used to calculate Kp.
What is the basis for calculating the equilibrium constant, Kp?
Kp is calculated based on the experimental measurements of the partial pressures of gaseous reactants and products at equilibrium.
What two types of experimental observations can be used to calculate equilibrium constants?
Equilibrium constants can be calculated from observations of either the concentrations or the partial pressures of the species in a reaction at equilibrium.
If you are given the partial pressures of all gases in a reaction vessel at equilibrium, which equilibrium constant can you determine?
You can determine Kp, which is calculated from the partial pressures of reactants and products at equilibrium.
From what source is the data used to determine an equilibrium constant obtained?
The data is obtained from experimental measurements of the concentrations or partial pressures of the substances involved in the reaction.
An experiment measures the molarity of all aqueous reactants and products in a system at equilibrium. Which equilibrium constant can be directly calculated from this data?
Kc can be directly calculated, as it is based on the equilibrium concentrations of the species.
Can you calculate an equilibrium constant from the initial concentrations of reactants?
No, equilibrium constants can only be determined from the concentrations or partial pressures of reactants and products measured at equilibrium.
What is the critical condition that the system must be in when measurements are taken to calculate an equilibrium constant?
The system must be at equilibrium when the concentrations or partial pressures of reactants and products are measured.
Equilibrium Constant
A value determined from experimental measurements of the concentrations (Kc) or partial pressures (Kp) of the reactants and products at equilibrium.