C14 - Crude oil and fuels (PAPER 2) Flashcards
What is crude oil
a thick black liquid made of many different compounds, mainly hydrocarbons
What is a hydrocarbon
a compound containing only hydrogen and carbon
How is crude oil formed
over millions of years from the remains of ancient biomass
WHat are alkanes
hydrocarbons that only have single bonds
What three properties affect a hydrocarbon’s usefulness as a fuel
flammability, boiling point, viscosity
how does the chain length affect viscosity, boiling point and flammability
the longer the chain, the
- higher the boiling point
- higher the viscosity
- lower the flammability
What are the first four alkanes
methane, ethane, propane, butane
What is the general formula for alkanes
C(n)H(2n+2)
How can the different alkanes in crude oil be separated
fractional distillation
What is a fraction
a group of hydrocarbons with similar chain lengths
What are 5 useful fuels produced from fractional distillation
petrol, diesel, kerosene, heavy fuel oil, liquified petroleum gases
What are four useful materials produced from crude oil fractions
solvents, lubricants, polymers, detergents
What is cracking
breaking down a hydrocarbon with a long chain into smaller molecules
What two methods are used to carry out cracking
- explain the process for each
steam and catalytic cracking
- catalytic - vaporise hydrocarbons and pass them over a hot catalyst at approx 550 degrees C
- steam - mix the hydrocarbons with steam at a high temperature and pressure (above 800 *C)
What are the products of cracking
short chain alkanes and alkenes
