Grade 10 · Reaction Rates · Factors Affecting Rate
What Affects Reaction Rates
Temperature, concentration and surface area explained by collisions.
Learning objectives
- Describe factors that affect reaction rate.
- Explain rate changes using collision theory.
- Process rate data and identify trends.
NGSS alignment
HS-PS1-5
Apply scientific principles and evidence to provide an explanation about the effects of changing the temperature or concentration of the reacting particles on the rate at which a reaction occurs.
HS-PS1-6
Refine the design of a chemical system by specifying a change in conditions that would produce increased amounts of products at equilibrium.
MS-PS1-6
Undertake a design project to construct, test, and modify a device that either releases or absorbs thermal energy by chemical processes.
MYP criteria
- Criterion B — Inquiring and Designing
- Criterion C — Processing and Evaluating
ENGAGE
Why does a splinter burn faster than a log?
EXPLAIN
Collision theory
Reactions happen when particles collide with enough energy. Anything that increases the frequency or energy of collisions increases the rate.
- Higher temperature: particles move faster, more energetic collisions.
- Higher concentration: more particles per volume, more collisions.
- Larger surface area: more particles exposed to react.
- Catalyst: provides an easier route, lowering activation energy.
Criterion C skill
Rate is often the gradient of a graph. A steeper line at the start means a faster reaction.
Interactive simulation · PhET
Concentration
Add solute and change the water volume, then watch how concentration changes — more concentrated solutions mean more collisions and faster reactions.
While you explore
- How does adding more solute change the concentration?
- Why do more concentrated solutions react faster?
- What happens to concentration when you add water?
Key vocabulary
- Collision theory
- The idea that particles must bump into each other hard enough to react.
Practice questions
0/2 correct
Level 1
Increasing the temperature increases reaction rate mainly because particles...
Level 2
Powdered marble reacts faster than a marble chip of the same mass because it has a greater...
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