A scientist measured the rate of diffusion of a gas across a membrane at different concentration differences.
The surface area and thickness of the membrane were kept the same.
The Table shows the results.
Table
| Concentration difference in arbitrary units | Rate of diffusion in arbitrary units |
|---|---|
| 10 | 4 |
| 20 | 8 |
| 30 | 12 |
| 40 | 16 |
| 50 | 20 |
Describe the relationship between the concentration difference and the rate of diffusion.
Predict the rate of diffusion when the concentration difference is 35 arbitrary units.
The scientist repeated the investigation using a membrane that was twice as thick.
Predict the rate of diffusion at a concentration difference of 40 arbitrary units.
Give a reason for your answer.
Explain why the scientist kept the surface area of the membrane the same.
42 exam-style questions on Edexcel GCSE Biology 8.1 Exchange surfaces and diffusion, covering 8.1.1 Introduction to exchange and transport, 8.1.2 Alveoli adapted for gas exchange, 8.1.3 Factors affecting rate of diffusion, and 8.1.4 Rate of diffusion using Fick's law. Each one has a worked solution and a mark scheme showing where the marks go.