Year 10 Science · Unit 2 · Lesson 12

Concentration and Surface Area

Challenge Worksheet

Name

Date

Class

Learning Goals

Design a full investigation comparing the effect of particle size on reaction rate.
Predict graph shapes for different particle sizes and explain them using collision theory.
Identify safety considerations specific to surface area experiments.

Go Deeper

Design a mini-experiment

A scientist wants to test: "How does particle size of calcium carbonate (CaCO₃) affect the rate of reaction with 1.0 mol/L hydrochloric acid?" Three particle sizes will be compared: large chips, medium chips, and fine powder (same mass for all). Plan the full investigation below.

What I will change (independent variable)
What I will keep the same (controlled variables, list at least 4)
What I will measure (dependent variable)
Step-by-step method (at least 5 steps)
Data table (design columns and rows with units)
Safety, risk of fine powder and acid; controls
Expected graph, describe the shape for each particle size (same axes). Do the curves end at the same volume? Why?

Show What You Know

1. After running the investigation, a student notices that the fine powder produced CO₂ three times faster than the large chips in the first 30 seconds, but the total CO₂ after 10 minutes was identical for all three. Use collision theory and the concept of limiting reactant to explain both observations.

Challenge 4 marks

2. A classmate proposes measuring the mass lost by the reaction flask instead of collecting CO₂ gas volume. Evaluate this alternative method, what are its advantages and one potential source of error?

Challenge 3 marks

Wrap Up

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