A laboratory model of an exchange surface uses a synthetic membrane that separates two solutions of the same solute. In the first test, the solute concentrations on the two sides of the membrane are 20 and 8 arbitrary units. In a second test, they are 14 and 8 arbitrary units. The membrane thickness, temperature and membrane material are the same in both tests, but the membrane area can be changed. The diffusion rate in the second test must be 1.5 times the rate in the first test.
Using Fick's law, what membrane area is needed in the second test?
1.5 times the area used in the first test
2 times the area used in the first test
3 times the area used in the first test
0.5 times the area used in the first test
102 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.