A technician has three test tubes of gas, X, Y and Z. One contains oxygen, one contains hydrogen and one contains carbon dioxide. The technician tests each gas. The table shows the results.
| Gas | Glowing splint | Lighted splint | Limewater |
|---|---|---|---|
| X | relights | burns more brightly | no change |
| Y | goes out | squeaky pop | no change |
| Z | goes out | goes out | turns milky |
Identify gases X, Y and Z.
Give the reason why the glowing splint relights in gas X.
The technician made gas X by decomposing hydrogen peroxide using a catalyst. Balance the equation for this reaction.
...H2O2→...H2O+O2\mathrm{H_{2}O_{2}} \rightarrow ...\mathrm{H_{2}O} + \mathrm{O_{2}}H2O2→...H2O+O2
A student says, "If a glowing splint goes out in a gas, the gas must be carbon dioxide."
Use the results in the table to explain why the student is wrong.
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.