Which observation is a positive oxygen test?
A glowing wooden splint bursts back into flame
A squeaky pop occurs
A white precipitate forms
A lit splint is extinguished
97 exam-style questions on Edexcel GCSE Chemistry 9.2 Earth and atmospheric science, covering 9.2.1 The Earth's early atmosphere, 9.2.2 How the atmosphere evolved, 9.2.3 Chemical test for oxygen, and 9.2.4 The greenhouse effect and climate change. Each one has a worked solution and a mark scheme showing where the marks go.