Lesson · S.3.4

What affects the rate of a reaction

Temperature, concentration, surface area, and catalysts, and how each one speeds up or slows down a chemical reaction on the TEAS.

ObjectiveS.3.4Read1 minExam weightChemistry ≈ 18% of Science

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What you will be able to do

  • Explain how temperature, concentration, surface area, and catalysts affect reaction rate.
  • Predict which of two conditions will produce a faster reaction.
  • Distinguish how added heat affects endothermic versus exothermic reactions.

What the lesson concludes

  • Raising temperature speeds most reactions up by increasing particle energy and collision force.
  • Higher concentration means more particles available to react, so the reaction speeds up.
  • Greater surface area exposes more particles to collisions, speeding a reaction.
  • A catalyst lowers the energy barrier to reaction without being consumed, so more collisions succeed.
  • Endothermic reactions tend to speed up with added heat; exothermic reactions can slow down.