The electrolysis of water

Electrolysis

Water is a compund. The electrolysis of water produces hydrogen gas and oxygen gas.

Water molecules contain two atoms of hydrogen chemically joined to one atom of a oxygen. The formula of water is H20. Electrolysis decomposes water into hydrogen (H2) and oxygen (O2).

Hydrogen

Hydrogen is a flammable gas. It can explode when it is mixed with air. Containers of hydrogen have the flammable hazard symbol on them.

Testing gases

The gases produced in reactions can be tested to find out what they are.

Gas:        Hydrogen        

Test:       Hold a lighted splint in the mouth of te test tube.

Results:  If the gas is hydrogen, it will explode with a squeaky 'pop'           

Gas:       Oxygen

Test:      Hold a glowing splint in the mouth of the test tube (light the splint, then blow it out so that the  

end is just glowing)

Results:  If the gas is oxygen the splint will relight (burst into flames) again

Gas:       Chlorine 

Test:      Hold a piece of damp blue litmus paper in the mouth of the test tube

Results:  If the gas is chlorine the paper will turn red and then turn white.