C7 Organic chemistry Flashcards
What is crude oil?
Crude oil is a finite resource found in rocks, made from the remains of ancient biomass, mainly plankton, buried in mud.
What are hydrocarbons?
Hydrocarbons are molecules made up of hydrogen and carbon atoms only.
What is crude oil composed of?
Crude oil is a mixture of a very large number of compounds, mostly hydrocarbons.
What type of hydrocarbons are most common in crude oil?
Alkanes.
What is the general formula for alkanes?
CnH2n+2.
Name the first four alkanes.
Methane (CH4), Ethane (C2H6), Propane (C3H8), Butane (C4H10).
How can hydrocarbons in crude oil be separated?
By fractional distillation.
What is fractional distillation?
A process that separates hydrocarbons into fractions based on their boiling points.
What are some fuels produced from crude oil?
Petrol, diesel, kerosene, heavy fuel oil, liquefied petroleum gases.
What industries rely on petrochemicals?
The production of solvents, lubricants, polymers, and detergents.
How do boiling point, viscosity, and flammability change with increasing hydrocarbon size?
Boiling point: Increases
Viscosity: Increases (becomes thicker)
Flammability: Decreases
What happens during the complete combustion of hydrocarbons?
Carbon and hydrogen are oxidised, producing carbon dioxide and water.
Write a balanced equation for the complete combustion of propane (C3H8).
C3H8 + 5O2 → 3CO2 + 4H2O.
What is cracking?
Cracking is the process of breaking down large hydrocarbons into smaller, more useful molecules.
Name two methods of cracking
Catalytic cracking and steam cracking
What are the products of cracking?
Smaller alkanes and alkenes.
How can you test for alkenes?
Use bromine water. If alkenes are present, the bromine water changes from orange to colourless.
Why is cracking useful?
: It produces smaller, more useful hydrocarbons, including fuels and materials for making polymers.
