Testing for Carbon Dioxide gas

Aim: To show that carbon dioxide is produced when a metal carbonate reacts with acid.

Equipment:

Two boiling tubes
Delivery tube and bung
Test tube rack
Wooden splint
Hydrochloric acid (the acid)
Calcium carbonate (the metal carbonate)
Test tube tongs
Safety glasses
Lighter

Method:

1. Add a pea-sized amount of the metal carbonate into one of the boiling tubes.
2. Place this boiling tube into a test tube rack. Ensure you have the bung and delivery tube ready.
3. Add 5ml of acid to the boiling tube and quickly insert the bung and delivery tube into the mouth of the boiling tube.
4. Holding the other boiling tube with your tongs, capture the gas produced. 
5. When you think that the tube is full, light a wooden splint. 
6. Carefully remove the boiling tube from under the delivery tube, taking care to keep it facing upward. 
7. Insert the burning splint into the mouth of the test tube. 

Results:

Test 1 including the stated experiment showed the splint going out in an instant within entering the test tube. It had choked and died due to having no oxygen within the space

Test 2 with lime water in the receiving tube and without the splint lighting showed the liquid within the receiving tube grow cloudier and foggier.

Discussion:

Within the experiment, we watch a chemical occur between the metal carbonate (the calcium carbonate) and the acid (the hydrochloric acid).

Calcium carbonate + Hydrochloric acid = Calcium chloride + Carbon dioxide + Water

As the gas went through the delivery tube the receiving tube filled with gas and had it gone longer it would have left a mixture of carbon dioxide and calcium chloride in the first boiling tube.