Dynamic equilibrium
High School
Definition
A state in a reversible reaction where the forward and reverse reactions occur at the same rate, so the concentrations of reactants and products stay constant. The reaction has not stopped; both directions continue at equal speed.
Worked examples
\(\)N\(_2\)O\(_4(g) \rightleftharpoons 2\)NO\(_2(g)\) in a sealed flask
Once equilibrium is reached, both gases keep reacting in both directions at equal rates, so their concentrations stay fixed.
Ice water in a sealed thermos at \(0^\circ\)C\(\)
Ice melts and water freezes at the same rate, so the amounts of ice and liquid water remain constant.
Common mistakes
- At equilibrium the reaction has stopped → At equilibrium both forward and reverse reactions continue at equal rates Dynamic means the reactions are still happening; they just balance each other out.
- Equal concentrations of reactants and products at equilibrium → Equal rates of forward and reverse reactions; concentrations can differ Equilibrium means equal speeds, not equal amounts.
- Only closed systems can reach equilibrium → Dynamic equilibrium requires a closed system to prevent material loss In an open system, reactants or products escape, preventing constant concentrations.
Where you'll use it next
Dynamic equilibrium is central to studying Le Chatelier's principle, equilibrium constants, acid-base chemistry, solubility, and phase changes in chemistry and later chemical engineering.
Found in 1 StudyPug lesson
Mastering Dynamic Equilibrium: Where Stability Meets Change
12th Grade12thChemistry 12
Dive into the fascinating world of dynamic equilibrium! Our introductory video breaks down this complex concept, showing how systems maintain balance despite constant internal changes. Perfect for chemistry and beyond!
See also
Reviewed by Pat Cheng, M.Ed. — StudyPug Curriculum Lead · Last updated June 6, 2026