A student puts some pondweed in a test tube of water and places it in bright light. Bubbles of gas are given off by the pondweed. The student collects the gas. Which test and result would show that the gas is oxygen?
A lit splint is put in the gas and gives a squeaky pop.
A glowing splint is put in the gas and relights.
The gas is bubbled through limewater and it turns milky.
Damp litmus paper is put in the gas and is bleached.
117 exam-style questions on OCR GCSE Biology 1.4 Photosynthesis, covering 1.4.1 Photosynthesisers as biomass producers, 1.4.2 Factors affecting the rate of photosynthesis, and 1.4.3 Limiting factors in photosynthesis. Each one has a worked solution and a mark scheme showing where the marks go.