Which gas is it
A candle tells hydrogen from oxygen.
Two test tubes
Two gases are collected from water, one in each test tube. You bring a burning candle near each mouth.
What could the candle show?
What this lesson covers
The idea
A burning candle brought near a gas identifies it: hydrogen burns with a pop sound, while oxygen makes the flame glow brighter.
Two test tubes
Two gases are collected from water, one in each test tube. You bring a burning candle near each mouth.
What could the candle show?
- Which gas is which
- Nothing
- Only the colour of the gas
Candle test
Open both tabs.
Spot the gas
A burning candle near the mouth of each test tube identifies the gas.
Hydrogen burns with a pop sound. Oxygen makes a burning candle's flame glow brighter.
- Gas | Candle test
- Hydrogen | Pop sound
- Oxygen | Flame glows brighter
Notes
Hydrogen: pop sound. Oxygen: flame glows brighter.
Check yourself
A burning candle near a gas gives a pop sound. The gas is …
A candle flame glows brighter near a gas. The gas is …
Hydrogen near a burning candle …
How do we identify the two gases from water?
- hydrogen — correct. Yes!
- oxygen. Oxygen makes the flame glow brighter.
- water. Water is a liquid. The pop sound shows hydrogen.
- hydrogen. Hydrogen gives a pop sound.
- oxygen — correct. Yes!
- nitrogen. Oxygen makes the flame glow brighter.
- makes the flame brighter. That is oxygen.
- puts out no sound. Hydrogen burns with a pop sound.
- burns with a pop sound — correct. Yes!
- With a burning candle — correct. Yes!
- By their taste. We use a burning candle.
- By their weight. The test uses a burning candle.