Year 10 Science · Unit 2 · Lesson 11

What Affects Reaction Rate?

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Learning Goals

Trace the cause-and-effect chain linking temperature to increased reaction rate via collision theory.
Compare all four factors affecting reaction rate using mechanism, example, and measurement.
Select an appropriate method for measuring how each factor affects rate.

Warm Up

Because… chain

Each row on the left is one step, and the next row is what happens after it. In the box, write the because — the reason that step forces the next one. Do not copy the next step’s words back; explain what makes it follow.

Temperature of the reaction mixture increases

→

Particles have more kinetic energy

→

Particles move faster

→

Collisions are more frequent and more energetic

→

Overall outcome: More collisions exceed the activation energy, so…

Your Turn

Compare the four factors affecting reaction rate

Complete the table. For each factor, explain the mechanism (how it changes the number or energy of collisions), give a real example, and suggest how you could measure the effect in a lab.

Factor	Mechanism (how it works)	Real example	How to measure it
Concentration
Surface area
Temperature
Catalyst

Show What You Know

1. A student dissolves marble chips (CaCO₃) in hydrochloric acid and measures the volume of CO₂ gas produced. They run the experiment at 25°C, then again at 50°C with everything else the same. Predict what will happen to the rate and explain why, using collision theory.

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Wrap Up

In one sentence, what was the main idea of this lesson?