Crude Oil Flashcards
Crude oil is
A mixture of hydrocarbons
How does fractional distillation separate crude oil into fractions
Crude oil is separated by fractional distillation
Crude oil is heated and the oil evaporates into gas
The gas rises up the fractional distillation tower where it is cooler at the top and hotter at the bottom
As the gas rises the temperature falls and they condense
Fractions with higher boiling points condense and are collected nearer the bottom of the tower
Names and uses of the main fractions:
Ralph Goes Killing Dogs For Breakfast
Refinery gases - Bottled gas
Gasoline - Fuel for cars
Kerosene - Fuel for aeroplanes
Diesel Oil - Fuel for lorries
Fuel Oil - Fuel for ships
Bitumen - Road surfacing
As the chain length of the hydrocarbons increase:
Boiling point increases
Viscosity increases (difficult to flow)
Darkness in color increases
Volatility decreases
Fuel definition
A substance that releases heat energy when burned
Why is carbon monoxide poisonous
It reduces the capacity of the blood to carry oxygen
Why can oxides of nitrogen form in car engines
When fuels are burned in engines, high temperatures are reached
At these high temperatures nitrogen and oxygen from the air react to produce nitrogen oxides
In the atmosphere these nitrogen oxides and combine with water to produce nitric acid
How is sulfur dioxide formed from combustion of fuels
Fossil fuels such as coal, gas and oil are derived from crude oil
These fuels contain impurities such as sulfur
When the fuels are burned, sulfur dioxide is produced which can escape into the atmosphere
S + O2 -> SO2
How do sulfur dioxide and oxides of nitrogen oxides contribute to acid rain
Sulfur dioxide released in the atmosphere can react with water and oxygen to make sulfuric acid (2H2SO4)
Sulfur dioxide reacting with just water -> weaker sulfurous acid (H2SO3)
Nitrogen oxide can produce nitric acid
Effects of acid rain
Kills trees and fish in lakes
Corrodes limestone buildings and marble statues
Some metals such as iron are also attacked by acid rain
Cracking conditions and method
Conditions: 600°C, alumina catalyst (Al2O3)
The thermal decomposition of long chain alkanes into shorter-chain alkanes and alkenes
Why is cracking necessary
Cracking converts long chain hydrocarbons into short chain hydrocarbons
Long chain alkanes are broken down into alkanes and alkenes of shorter length
Crude oil contains a surplus long chains
Shorter chain hydrocarbons are in greater demand, e.g. petrol
Cracking also produces alkenes which are used in making polymers and ethanol
