Combustion

• For complete combustion, heat, oxygen and fuel are needed.
• During complete combustion, carbon dioxide + water is produced
• During imcomplete combustion, carbon monoxide and soot (carbon) are produced.
• Carbon monoxide is poisonous as it stops the blood from carrying oxygen around the body.
• Carbon dioxide extinguishers replace the oxygen with carbon dioxide as oxygen keeps it burning
• Water extinguishers remove heat from the fire to stop it from burning
• We test for oxygen by placing a glowing splint in a tube of oxygen gas - if it relights oxygen is present
• We test for carbon dioxide by putting CO2 gas into limewater - if it turns cloudy then CO2 is present
• We test for hydrogen by placing a lit splint in a tube of hydrogen gas - if it makes a popping sound, hydrogen is present
• We test for chlorine by putting damp litmus paper into chlorine gas - if litmus paper turns blue, chlorine is present
• Hydrocarbons are made of Carbon and Hydrogen only
• To test for water, we take cobalt chlorine paper and if it turns from blue to pink upon impact with the substance, water is present
• Alkanes have the general formula: CnH(2n+2)
• Incomplete combustion happens when there is not enough oxygen to burn a fuel fully
• Alkanes have a single bond, whereas alkenes have a double bond
• Combustion is a chemical reaction when a fuel is burnt in oxygen to produce carbon dioxide and water
• CH4 + 202 --> CO2 + 2H2O

  methane