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Hydrogen properties
Chemistry

Hydrogen properties

To demonstrate two principal properties of hydrogen.

Preparing and testing gases
hydrogen; gas tests; combustion

What students learn

The science behind this experiment

Hydrogen is a flammable gas with other interesting properties. It is highly explosive, but it is also lighter than air and diffuses rapidly because it is a small molecule.

Equipment used

  • Iron stand — 5404.52
  • Universal clamp — 5416.20
  • Right angle clamp — 5401.16
  • Conical flask 150 ml — 1322.10
  • Rubber stopper, 2 holes — 5450.80
  • Dropping funnel — 1359.00
  • Right angle bent glass delivery tube — 1468.07
  • Connection for glass delivery tubes — 5449.43
  • Dropping pipette — 1441.50
  • Test tube — 1473.60
  • Spatula — 5460.34
  • Cork stopper to fit test tube (not a rubber stopper) — 5453.20
  • Parafilm — 1646.00
  • Matches

Chemicals and reagents

  • Hydrochloric acid 2 M — R:34-37 S:26-45
  • Granulated zinc
  • Distilled water

Safety notes

  • Hydrogen is a very flammable gas and forms explosive mixtures with air. Remove any naked flame to a safe distance — preferably have no flames on the same bench as the apparatus.

Questions for students

  • Record your observation of what happens on igniting the gas.
  • Record what happens keeping the test tube vertical. What can you say about the weight of hydrogen with respect to air?
  • Record what happens, and explain it.

What to expect

<p>The combustion of the hydrogen causes the production of water in a very exothermic reaction. 2H2 + O2 → 2H2O + heat.</p><p>The water vapour formed condenses on the walls of the test tube.</p><p>There is no explosion and no burning gas.</p><p>Hydrogen is lighter than air. Placing the test tube in a vertical position allows it to escape and the test tube is filled with air.</p><p>Because of the small mass of the hydrogen molecule, the gas diffuses very rapidly.</p>

Disposal

Add plenty of water to the conical flask and dispose of the liquid into the liquid wastes container. Dispose of the zinc residues in the solid wastes container.

Run this experiment in your classroom

This experiment is part of the ATP Mobile Lab — a self-contained laboratory that turns an ordinary classroom into a working science lab, with over 200 experiments in physics, chemistry, biology, robotics and engineering. Gali, the AI tutor built into ATP Connect, guides students through each step and answers their questions at the bench.

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