Properties of Hydrogen Gas
Explore physical properties and combustion of hydrogen.
What this lesson covers
Why it matters
A balloon of hydrogen tugs upward, escaping your hand. Bring a flame near and it answers with a sharp squeaky pop — the classic test for hydrogen.
Predict first
Why does a hydrogen balloon float upward?
Hydrogen is the lightest gas — colourless, odourless, lighter than air, and it burns with a squeaky pop. It is used as a clean fuel and to make ammonia.
- Hydrogen is much lighter (less dense) than air — correct
- Hydrogen is heavier than air
- The balloon is actually empty
What you do
Sort each statement: true of hydrogen, or false?
Check yourself
The lab test for hydrogen gas is…
Milky lime water tests for CO₂ and relighting tests for O₂; hydrogen gives the pop.
Hydrogen floats up in air because it is…
Being the lightest of all gases, hydrogen rises in air.
Why is hydrogen called a CLEAN fuel?
2H₂ + O₂ → 2H₂O: the only product is water vapour. That is why hydrogen is prized as a pollution-free fuel.
- a lighted splint burns it with a squeaky pop — correct
- it turns lime water milky
- it relights a glowing splint
- less dense (lighter) than air — correct
- denser than air
- the same density as air
- Burning it produces only water — no smoke, no CO₂ — correct
- It burns without releasing any energy
- It puts out fires instead of feeding them