Oxygen

We can prepare oxygen in the laboratory by reacting hydrogen peroxide and manganese dioxide according to the equation below.

2H2O2(aq) => 2H2O(l) + O2(g)

The manganese dioxide acts as a catalyst.
The serpent is a fantastic demonstration of the decomposition of hydrogen peroxide into oxygen and water.

Click to see a demonstration of this reaction.

Properties of oxygen
Supports combustion Click to see a 120 kb video. The video shows a glowing wick placed in oxygen.
Oxygen reacts with most metals (corrosion) and non-metals. Click to see a 120 kb video. The video shows red hot steel wool in oxygen.
Odourless and colourless.  
Oxygen is slightly soluble in water but enough is present to support marine life.

 
Oxygen can be identified by placing a glowing splint of wood into a test tube of oxygen gas. The splint re-ignites. Click to see a 120 kb video.
Continue with hydrogen