Revision Flashcards
Crude oil and petroleum
Petroleum is a complex mixture of organic liquids called crude oil and natural gas
What is crude oil an important source of….
Fuels e.g petrol, diesel, kerosene
Visocity
A measure of a fluid’s resistance to flow
Viscosity increases/ decreases as you move down the fractional column
Decreases
Why do longer carbon chains have a higher viscosity
They have a larger surface area for dispersion forces to act across
Why do smaller molecules have lower viscosity
Have shorter chains so they have less surface area for dispersion forces to act across
Fractional distillation top to bottom
Refinery gas, gasoline, naphtha, paraffin, diesel, fuel oil, lubrication oil, bitumen
What is refinery gas used for
Heating and cooking esp. where piped gas cannot be used
Gasoline uses
Fuels for cars
Naphtha uses
Making chemicals especially plastics
Paraffin uses
Fuel for Jet aircraft
Diesel oil uses
Used in diesel engines such as trucks and tractors
Fuel oil (heavy fraction) use
Used for fuel for ships and home heating systems
Lubrication oil uses
Used for lubricants, waxes and polishes
Fossil fuels and green chemistry principles
Crude oil is a finite resource that takes millions of years to form-> renewable alternatives= necessary e.g plant-based biomass is a renewable source of many everyday chemicals
What challenges are currently faced in finding new alternatives for crude oil
Cost, practicability, sustainability, ethics
At top of fractional distillation
Shorter hydrocarbons, low viscosity(Runny), easy to ignite, low boiling point, few intermolecular forces
At bottom of fractional distillation
Longer hydrocarbons, high viscosity- thick, harder to ignite, high boiling point, more intermolecular forces
Process of f.d
1.Crude oil is heated
2. Long hydrocarbon chains remain as liquid at base of tower and topped off in liquid form I.e bitumen
3. Shorter chains vaporise and rise up the tower
4. As the hydrocarbons reach their bopiling point in the tower, they condense from gas to liquid and are tapped off
Cracking method
Hydrocarbon molecules are heated until they turn to vapour, and then are mixed using a catalyst
Catalytic cracking done in lab
- Heat mineral wool soaked in oil with a catalysts producing a gas
- Oil will likely be a long chain hydrocarbon, the catalyst is heated and not oil b/c oil= flammable.product being gaseous suggests that we gave produced molecules with a smaller size than that of the oil
Why does a large sa aid catalysis
More reactant particles can pass over the catalyst and form products
What is suck-back
When cold water is drawn upwards into the delivery tube and into the hot boiling tube
What can you do to prevent suck-back
Take the delivery tube out of the water before you stop heating
