The rate of reaction tells you how quickly a reaction goes, and the lessons here link three things: what a graph shows, why particles react faster or slower, and how to compare experiments fairly.
This section is part of SPM Chemistry. It connects to thermochemistry through energy diagrams.
How do the parts connect?
The lessons follow a chain of four skills.
- Read an average or instantaneous rate from a graph.
- Explain why a factor changes the rate using collision theory.
- Compare two graphs fairly, changing one variable at a time.
- Interpret an activation-energy diagram to see why a catalyst works.
The first skill gives you the numbers, and the others give you the reasons.
One short example
A student collects 40 cm³ of gas in the first 50 seconds. The average rate is 40 ÷ 50 = 0.80 cm³ s⁻¹.
Later, only 10 cm³ is collected in the next 50 seconds, giving an average of 0.20 cm³ s⁻¹. The rate fell because the reactant was being used up. That single comparison already links a graph reading to a particle explanation.
Who should start where?
Choose the lesson that matches the gap you notice most.
| Your difficulty | Start with |
|---|---|
| Finding a rate from a graph or a tangent | calculating average and instantaneous rates from graphs |
| Explaining a factor in words | explaining factors using collision theory |
| Comparing two experiments | comparing rate graphs fairly |
| Energy diagrams and catalysts | interpreting activation-energy diagrams |
When the four feel steady, mix them in the rate of reaction practice set.
To have a teacher connect the graphs and the theory with you, see online one-to-one Chemistry tuition.