When a substance burns what is it reacting with? Oxygen
Name the type of compound found in oil and natural gas. Hydrocarbons
What is a hydrocarbon? A compound which contains hydrogen and carbon only.
Name the two products formed when a hydrocarbon burns in a plentiful supply of oxygen (complete combustion) Carbon dioxide and water
What is the test for carbon dioxide? Limewater turns milky
Name the poisonous gas produced when a hydrocarbon burns in a limited supply of oxygen (incomplete combustion). Carbon monoxide
What is produced when nitrogen and oxygen from the air react inside a petrol engine ? Oxides of nitrogen which are poisonous
What causes nitrogen and oxygen from the air to react inside a petrol car engine? Spark
Why is it dangerous to burn fuels containing sulphur compounds? Sulphur dioxide is produced (a poisonous gas)
Name the harmful particles produced by the incomplete combustion of diesel. Soot
What does a catalytic converter do? Converts pollutant gases into harmless gases. Carbon monoxide into carbon dioxide Oxides of nitrogen into nitrogen
Name the type of chemicals compounds found in crude oil. Hydrocarbons
Name the process used to separate crude oil into fractions. Fractional distillation
What is a fraction? A mixture of hydrocarbons with similar boiling points
What property allows the hydrocarbons to be separated by fractional distillation? They have different boiling points
Which size of hydrocarbon molecules have the largest boiling point? largest molecules - as the molecules become larger the boiling point increases.
Describe what happens to ease of evaporation, viscosity and flammability as the molecular size increases. As the molecular size increases - ease of evaporation decreases - more viscous(thicker) - less flammable
Why is lubricating oil more viscous than petrol? Lubricating oil contains longer hydrocarbons than petrol.
Is air a mixture of gases or a compound? A mixture of gases
Name the gas which turns lime water milky? Carbon dioxide
What is the test for oxygen gas? Relights a glowing splint
Why should sulphur dioxide not be released into the atmosphere? It causes acid rain
Give a use for the residue fraction. Tar for roads/roofing
Approximately how many carbon atoms are in the hydrocarbon molecules used to make petrel? 8 carbons C 8 H 18