Carbon Dioxide

Carbon Dioxide

Preparing It in the Lab

Carbon dioxide is made by the reaction between dilute hydrochloric acid and calcium carbonate in the form of marble chips.

CaCO₃(s) + 2HCl(aq) à CaCl₂(aq) + CO₂(g) + H₂O(l)

Formation of Carbon Dioxide from Thermal Decomposition of Metal Carbonates

Key thing here: When heating metal carbonate, you get:

Metal Carbonate -> Metal Oxide + Carbon Dioxide

Here is the picture of the experiment setup:

Properties of Carbon Dioxide

• Colourless gas, denser than air, slightly soluble in water
• Used in carbonated (fizzy) drinks because it dissolves in water under pressure. When bottle is opened, pressure falls and gas bubbles out of the solution.
• Used in fire extinguishers to put out electrical fires, or those caused by burning liquids, where using water could cause problems. The carbon dioxide sinks onto the flames and prevents any more oxygen from reaching them.
• Turns limewater cloudy white (limewater is calcium hydroxide – work out the equation yourself – water is one of the products).