Question

(d)

A teacher collected two tubes full of hydrogen gas, as shown in figure 3
She tested tube A with a lighted splint as soon as she took the bung out.
She tested tube B with a lighted splint a few seconds after taking the bung out.
(1) Suggest why tube B gave a much louder pop than tube A.

Answer 1

Step-by-step explanation:

This practical can be used to introduce the idea that the relative amounts of a fuel and oxygen (from air) are important in combustion, and that there will be an optimum ratio in which the two substances react. This leads on to the idea of chemical equations.

In the case of a class experiment, where students generate the hydrogen themselves under strict supervision, all the hydrogen generators must be collected once the test tubes have been filled and before any flames are lit, to prevent the possibility of accidental or deliberate ignition of the hydrogen in the generator. This has caused a number of accidents in the past. Alternatively the test tubes could be filled with hydrogen beforehand, or by students under supervision, from a steady cylinder supply.