Fractional Distillation Flashcards
What is crude oil made up of?
A mixture of hydrocarbons
What is crude oil?
Black smelly viscous liquid
What is a hydrocarbon?
Molecules which contain hydrogen and carbon atoms ONLY
Similar boiling points and similar chain lengths
What is fractional distillation?
- crude enters base of fractioning tower -heated
- Fractions evaporate
- when a gas reaches a point in the tower in condenses and goes into a tray
- Fractions of similar BOILING points are collected in the same tray
- The lightest gases have the LOWEST boiling points so they rise to the very TOP and are collected
Fractional distillation is…
Separation of hydrocarbons that boil at different temperatures
As the chain lengths of hydrocarbon fractions increase their properties change..
What happens to colour?
YELLOW ➡️ ORANGE ➡️ BROWN
Viscosity?
Runny ➡️ Hard to pour ➡️ Very hard to pour
Ease of ignition?
Easy to light ➡️ harder to light ➡️ difficult to light
Cleanliness of burning?
Clean ➡️ more polluted
E.g.
H20 + C02 ➡️➡️➡️➡️ CO (sut)
What are the four changes that happen to the properties of hydrocarbon fractions when their chain length increases?
Colour
Viscosity
Ease of ignition
Cleanliness of burning
What does saturated mean?
Contains Single Covalent bonds ONLY
Why are alkANES so unreactive?
They contain single covalent bonds only
A lot of energy will be required to break bonds
List the alkANES (4)
METHane
ETHane
PROPane
BUTane
What are AlkENES?
They contain at least one double bond between the carbon atoms
Unsaturated molecules
List 3 AlkENES
EthENE
PropENE
ButENE
What happens when AlkENES react with hydrogen?
They turn into alkANES
What are AlkENES used to make?
Polymers and plastics
What is an addition reaction that AlkENES undergo?
The joining together of two reactants to make one product
No Impurities/side reactions made
What happens when AlkENES react with bromine?
Br is added and the AlkENE becomes an alkANE
How do we test for an AlkENE?
Add bromine water
Bromine is normally ORANGE
Solution will turn COLOURLESS if present
What does a molecular formula show?
Which elements are present and how many of each
What does the structural formula show?
The bonds of the arrangements of the atoms
What is additional polymerisation?
When monomers join together to form polymers
Won’t happen if we don’t have high pressure or a catalyst
Description of additional polymerisation..
Double bond between two carbon atoms break
Arms open
Two straight lines through brackets
Joins another monomer to form new single covalent bond
