equilibrium constant
Let an agent handle equilibrium constants by expression, calculation, temperature dependence and applications, with sourced data.
Research draft, second pass
A second pass drafted this model: the structure a model of this thing needs, and what is known about it in the world. The line under this one says how the second half was obtained - researched against sources, or recalled without web access, in which case nothing here was read anywhere and every claim is a lead to verify. Unreviewed either way.
written by Claude from model knowledge without web access - no source was read, every claim is a lead to verify
Researched by: Claude
Purpose and description
Let an agent handle equilibrium constants by expression, calculation, temperature dependence and applications, with sourced data.
A number characterising the ratio of product to reactant concentrations or activities at chemical equilibrium for a given reaction and temperature, written K (Kc, Kp), with related constants such as the solubility product (Ksp), acid dissociation constant (Ka) and formation constants.
What it is for: Predicting the extent of reactions and composition at equilibrium.
It can be write equilibrium constant expressions; calculate equilibrium concentrations; relate K to Gibbs energy; look up constants from data tables.
Distinguishing features
Defined at equilibrium
Temperature-dependent
Related to Gibbs free energy
Many specialised forms
What it looks like
Not physical; written as K values in tables and equations.
How it is recognised
K, Kc, Kp, Ka, Ksp
Reaction quotient Q compares non-equilibrium states
Rate constants describe speed, not extent
Related models
is a kind of - category
includes - kind
is related to - thermodynamics
is contrasted with - kinetics
In practice
Families and kinds
Kc and Kp
acid and base dissociation constants
solubility products
formation and stability constants
partition coefficients (related)
Standards and regulation
IUPAC recommendations on equilibrium constants
Failure modes and hazards
Using K at the wrong temperature
Confusing K and Q
Ignoring activity corrections
Also called
Where this came from
wikidata · CC0 1.0
Also registered as vr.tr.equilibrium-constant
Drafted structure
Bundle to layer to finding to question, as the second pass will find it: 4 bundles · 8 layers · 8 findings · 16 questions.
Expression Writing K.
Expressions follow rules.
Write
Expression.
Write
Expression.
- How is the equilibrium constant expression written for this reaction? definition
- Which species are excluded, such as pure solids? definition
Type
Which constant.
Type
Constant type.
- Is Kc, Kp, Ka or Ksp meant? definition
- How do they relate? definition
Calculation Using K.
Calculations predict composition.
Concentrations
Equilibrium amounts.
Concentrations
Equilibrium concentrations.
- What are the equilibrium concentrations given these starting amounts? measurement
- Are approximations valid? boundary
Q
Reaction quotient.
Q
Reaction quotient.
- How does comparing Q with K predict the direction of reaction? definition
- What is Q here? measurement
Thermodynamics Temperature and energy.
K depends on temperature.
Gibbs
Free energy.
Gibbs
Gibbs energy relation.
- How is K related to the standard Gibbs energy change? definition
- What value results? measurement
Temperature
Van t Hoff.
Temperature
Temperature dependence.
- How does K change with temperature for this reaction? definition
- Is the reaction exothermic or endothermic? definition
Data Sources.
Values need sources.
Tables
Reference data.
Tables
Reference data.
- What is the tabulated value, and at what temperature and ionic strength? provenance
- Which data source is used? provenance
Teaching
Learning.
Teaching
Teaching.
- How can equilibrium constants be explained with a worked example? action
- Which misconceptions arise? boundary
What the second pass must settle
- Should constant types be separate entries?
- How should data tables be linked?
- How should activity corrections be explained?