Chemical analysis
AQA GCSE Chemistry revision on Chemical analysis. Aligned to the AQA GCSE Chemistry 8462 specification. This bank has 8 practice questions on this topic.
Sample questions (3 of 8)
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Question 1
The test for hydrogen gas is...
- A) Lighted splint - 'squeaky pop'
- B) Glowing splint relights
- C) Damp red litmus turns blue
- D) Limewater turns cloudy
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Answer: Lighted splint - 'squeaky pop'
Test for hydrogen: bring a lighted splint to the gas. H2 burns explosively in oxygen with a 'squeaky pop' sound. The product is water. The four main gas tests: H2 (squeaky pop), O2 (relights glowing splint), CO2 (turns limewater cloudy), Cl2 (bleaches damp litmus paper).
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Question 2
The test for oxygen gas is...
- A) Squeaky pop
- B) Glowing splint relights
- C) Universal indicator turns red
- D) Limewater turns cloudy
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Answer: Glowing splint relights
Take a wooden splint, light it, then blow it out so it just glows. If you put it into a gas + it RElights, the gas is oxygen. Oxygen supports combustion - the splint reignites in the pure O2 atmosphere.
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Question 3
The test for carbon dioxide is...
- A) Squeaky pop
- B) Limewater turns cloudy
- C) Litmus turns red only
- D) Glowing splint relights
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Answer: Limewater turns cloudy
Limewater is calcium hydroxide solution Ca(OH)2. Bubbling CO2 through it: CO2 + Ca(OH)2 -> CaCO3 (white precipitate, makes water cloudy) + H2O. Standard test in school labs.
Want to test yourself on the remaining cards for this topic?
5 more questions on Chemical analysis — plus mistakes tracking and spaced repetition across the whole Chemistry spec.