The atmosphere of Venus is about 96% carbon dioxide, similar to the Earth's early atmosphere. The surface of Venus is at about 460 ∘C460\,^\circ\mathrm{C}460∘C, and Venus has no liquid water and no living organisms.
Using ideas about how the Earth's atmosphere changed, which statement best explains why the atmosphere of Venus is still mainly carbon dioxide?
Its volcanoes are hotter, so they release more carbon dioxide than Earth's volcanoes did
Carbon dioxide is too dense to escape into space, so it has built up over time
No organisms have respired, so nothing has used up the carbon dioxide
No oceans formed for carbon dioxide to dissolve in, and no photosynthesis removed it
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.