Equilibria
Describe dynamic equilibrium and predict how concentration, pressure, temperature and catalysts affect equilibrium systems.
How to study Higher Chemistry
Move deliberately between structure, equations, quantitative models, unfamiliar evidence and justified experimental conclusions, while using current official materials for exact paper and assignment practice.
Core concepts
Concept 1
At dynamic equilibrium in a closed system, forward and reverse reactions continue at equal rates and concentrations remain constant but need not be equal.
Exam cue: State both equal rates and constant macroscopic composition when defining dynamic equilibrium.
Concept 2
A system responds to concentration, pressure or temperature change in the direction that opposes the imposed change.
Exam cue: For pressure, count gaseous moles on each side before predicting a shift.
Concept 3
A catalyst speeds forward and reverse reactions but does not change equilibrium position or equilibrium yield.
Exam cue: Treat heat as a reactant or product when reasoning about temperature.
Risk pitfalls and guardrails
Saying reactions stop at equilibrium.
Guardrail: Check structures, formulae, charges, equation balance, units, signs and experimental conditions before committing to the final conclusion.
Saying reactant and product concentrations become equal.
Guardrail: Check structures, formulae, charges, equation balance, units, signs and experimental conditions before committing to the final conclusion.
Claiming a catalyst shifts equilibrium toward products.
Guardrail: Check structures, formulae, charges, equation balance, units, signs and experimental conditions before committing to the final conclusion.
Memory anchors
Dynamic equilibrium
Forward and reverse reactions continue at equal rates in a closed system.
Constant, not equal
Equilibrium concentrations remain constant but are not necessarily equal.
Concentration change
The system shifts in the direction that consumes some of the added substance.
Pressure change
Higher pressure favours the side with fewer moles of gas.
Temperature change
Higher temperature favours the endothermic direction.
Catalyst at equilibrium
It reaches equilibrium faster but does not alter equilibrium position.
Checkpoint rule
Do the check-up only after you can summarize each concept in one sentence and identify one dangerous pitfall from memory.
Knowledge Check (after reading)
Short check-up to confirm understanding of this module.
Check-up Questions
Which statement correctly describes dynamic equilibrium?
At equilibrium, what happens to reactant and product concentrations?
Answer all questions to submit.
Next step personalized recommendations
Continue learning
Move forward only after this module is stable.
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