2.5 Crude Oil, Fuels and Organic Chemistry Flashcards
How is crude oil formed?
The remains of dead sea organisms sink to the bottom of the sea, over time the dirt builds up on top and then they decay anaerobically causing the shells of the dead organisms to form crude oil.
The crude oil rises and is trapped underneath rocks which we drill through to get to it.
What is crude oil a mixture of?
Hydrocarbons (hydrogen and carbon only)
What does the larger the hydrocarbon result in? Why?
The less volatile(difficult to get into a gas)
High melting and boiling point
More viscous
Less flammable
Because stronger intermolecular bonds
What is the fractional distillation process?
- Crude oil is a complex mixture of hydrocarbons
- Crude oil is heated to a vapour then put in a fractional distillation column
- Column is the hottest at the bottom and cools towards the top
- Hydrocarbons make their way up the column and condense at diff temp and collected on plates as fractions.
- Large hydrocarbons condense at the bottom and small condense higher up the column
What are the prefixes for up to five carbon atoms?
- Meth-
- Eth-
- Prop-
- But-
- Pent-
Are alkanes saturated or unsaturated? Do they have a double bond?
Saturated
No
What is the general alkane formula?
CnH2n+2
How do you name alkane isomers?
Number all the carbons
Put the number of the extra carbon at the beginning of the name (has to be lowest it can be
CH3
I
e.g C-C-C-C
2-Methyl butane
Are alkenes saturated or unsaturated? Do they have a double bond?
Unsaturated
Yes, one double bond
What is the general formula for alkenes?
CnH2n
How do you name alkene isomers?
Same of alkanes but the double bond must be the lowest.
e.g C-C=C-C-C
I
CH3
2-Methyl Pent-2-ene
What is isomerism?
Same chemical formula, different chemical structure
What is cracking?
to produce smaller and more useful
hydrocarbon molecules, including monomers (alkenes) which can be used to
make plastics
Answer : C10H22 -> C2H4 + C5H12 + ?
C3H6
What are addition reactions?
Addition of two atoms across the C=C bond in an unsaturated compound thus forming a saturated compound.
What is and identifying test for an alkene and alkane and what do they show?
Addition of bromine water
Alkenes decolourise
Alkanes have no change/stay brown
Answer : H H
I I
C=C + Br-Br ->
I I
H H
H H
I I
H - C-C - H
I I
Br Br
What are polymers and how are they formed?
Use of chemicals from crude oil to make plastic
Formed when many smaller molecules join together (monomers)
What are the key features of a monomer?
- double bond (so an alkene)
- no line through the bracket
- “n” before the bracket