How temperature, concentration, surface area, and catalysts change reaction rate, and how Le Chatelier's principle predicts which way an equilibrium shifts, worked through HESI A2 style examples.
ObjectiveC.2.3Read5 minExam weightBonding and Reactions ≈ 24% of Chemistry
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Name the four factors that speed up a chemical reaction and explain why each one works.
Define chemical equilibrium and read a reversible reaction's forward and reverse arrows correctly.
Apply Le Chatelier's principle to predict which direction an equilibrium shifts after a stress.
What the lesson concludes
Reaction rate rises with higher temperature, higher concentration, greater surface area, and the presence of a catalyst, though the first three work by raising the frequency or energy of particle collisions while a catalyst works by lowering the activation energy.
A catalyst speeds up a reaction by lowering its activation energy, and it is not consumed or permanently changed by the reaction.
Equilibrium is a state where the forward and reverse reaction rates are equal, not a state where the reaction has stopped or the concentrations are equal.
Le Chatelier's principle says a system at equilibrium shifts to partially counteract any stress placed on it, whether that stress is concentration, temperature, or pressure.
Adding a catalyst changes how fast equilibrium is reached but never changes where the equilibrium sits.