CHEMISTRY

OXIDES OF CARBON Carbon forms two important oxides, namely: 1. Carbon(IV) oxide, CO₂ 2. Carbon(II) oxide, CO                                                     Carbon (IV) oxide, CO₂ The atmosphere contains about 0.03% by volume of CO₂. A small percentage of CO₂ is also found dissolved in water. In the combined form, carbon is found mainly as metallic trioxocarbonates(IV) and hydrogen trioxocarbonates(IV) in the Earth's crust, especially in limestone regions and coral reefs. Preparation of CO₂ A. Laboratory Preparation CO₂ is prepared in the laboratory by: (i) Action of dilute acids on trioxocarbonates(IV) or hydrogen trioxocarbonates(IV) For example: CaCO₃(s) + 2HCl(aq) → CaCl₂(aq) + H₂O(l) + CO₂(g) Another example is: NaHCO₃(aq) + HCl(aq) → NaCl(aq) + H₂O(l) + CO₂(g) (ii) Heating metallic trioxocarbonates(IV) Except those of sodium and potassiu...

Carbon is a non-metal and occurs naturally in both free and combined states. In the free state, carbon occurs in different allotropic forms, including: 1. Diamond 2. Graphite 3. Amorphous carbon Carbon also occurs in the combined state in many substances, including: 1. Carbon(IV) oxide (CO₂) in the atmosphere and dissolved in water. 2. Metallic trioxocarbonates(IV), such as: Calcium trioxocarbonate(IV) (limestone), CaCO₃, Magnesium trioxocarbonate(IV) (dolomite), MgCO₃ 3. Petroleum 4. Natural gas 5. Coal 6. Wood and other living matter Carbon is an essential constituent of all living organisms. It is present in carbohydrates, proteins, fats and many other organic substances. The branch of chemistry that deals mainly with carbon compounds is known as organic chemistry.                                                Allotropes of Carbon Allotrope of carbon is...