Notesale: Turn your study into money

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SC20a: Crude oil
Fossils: coal, crude oil, natural gas from remains of dead animals- formed because of heat,
pressure and absence of oxygen

Crude oil
-Mixture of HYDROCARBONS (=contain hydrogen and carbon atoms only)
-Thick black liquid trapped in sedimentary rocks
-No-renewable energy source->Finite resource

SC20b: Crude oil fractions
Fractional distillation
=used to separate mixture of liquids that have different boiling points (the longer the
hydrocarbon is the higher the boiling point as the intermolecular forces of attraction
between molecules are stronger)
Eg: separates crude oil into mixtures of hydrocarbons called fractions (most are used as
fuels)

How is crude oil separated into fractions? (6mark)
1
...
Column-hot at bottom-cold at the → As vapour rises is cools and condenses at
different levels-boiling point
3
...
Light fractions (have small carbon chain molecules→are more useful/desirable)
→low boiling point→condense at the top of column
5
...

2
...

4
...
Hydrocarbon molecule with C-C single bond
2
...
Compounds end in a -ane
1
...

3
...


Methane→ Monkeys
Ethane→ Eat
Propane→Pink
Butane→Bananas

The rest follow numbers eg: Pentane, hexane
Types of Formula
1
...


Molecular= Actual number of atoms

3
...


Structural= All atoms using subscript numbers

5
...
Acidic lakes-soils→fish die
2
...
Marble things dissolve

SC20f: Breaking down hydrocarbons
Cracking: Breaking of large alkane molecules into smaller alkanes and alkenes→→usually is the first product
-The heavier molecules can be broken down into lighter ones using heat or a catalyst (aluminium oxide)
➔Thermal cracking=thermal decomposition reaction
=Hydrocarbon molecules are heated until they turn into vapour
=Alkanes and alkenes (reactive molecules-used for plastic and chemicals) are made
One product should always be an alkene
(CnH2n)

oil

Porous pot

The rest can be alkanes (CnH2n+2) or
hydrogens
Paraffin oil
- Volatile (low boiling point)
-Hydrocarbon to be cracked
Strong heat-Provides active sites
-Provides surface to make reaction
faster
Gases which are soluble cannot be
collected with this method

1
...

3
...


Allow the first few bubbles to escape→air originally in apparatus
Paraffin oil absorbed by wool to stop it from flowing along the tube
Pot is heated strongly
Paraffin oil is heated→evaporates and forms gas→heat causes some covalent bonds to
break➔cracked paraffin
5
...
Remove delivery tube just before turning off the heat→otherwise the gas will contract→water will
be forced back into the tube→tube will crack➔Suck-back
How to know if reaction ended?
1
...
Volume of gas stays the same (scale on measuring cylinder)

Choosing Fuels (6mark)
1
...

3
...

5
...


=features that help identify eg
...
Add a little bromine water (brown) to alkane/ alkene
2
...
Alkane? Stays orange brown

Addition reactions
=Reaction in which reactants combine to form one larger product molecule and no other products
-Double bond breaks
-Bromine takes its place
-“1,2” tell the position of bromine
-“di” is how many bromines

SC23a/b: The alcohols homologous series
Alcohols=
-Family of organic compounds whose molecules contain a hydrocarbon chain
→OH/ hydroxyl functional group
-GF : CnH2n+1OH
-Eg: Whiskey, vodka

Ethanol production

Uses:
1
...

Solvent
3
...

Starting material to make
chemicals

1
...


Reaction of Ethene with steam (hydration)

All alcohols produce
-CO2
Can be oxidised to form carboxylic
acids
-react with reactive metals

Alcohol with metals
Higher % are formed by fractional distillation

1
...
Metal dissolves
3
...

C2H5OH+Na→C2H5Na+1/2H2O(g)
➔OH is replaced by the metal

Combustion of ethanol=
C2H5OH+O2→ CO2+H2O

SC23c: Carboxylic acids homologous series
=Organic acids
-names end in -oic acid
-Ph=3-4
Very soluble in water

General formula:
CnH2n+1COOH (There is one less C in n as it counts the COOH C)
-COOH is always last or first and has a double bons C=O

Vinegar:

Ethanoic Acid
-Produced by oxidation of ethanol eg
...
g
...

Example: NaOH + CH₃COOH → CH₃COONa + H₂O

Reaction with Carbonates:
They react with carbonates (e
...
, Na₂CO₃) to form salts, water, and CO₂ gas (bubbles)
...

Example: Na + CH₃COOH → CH₃COONa + ½ H₂

Key Points:
-Carboxylic acids behave like weak acids, so reactions happen slower than with strong acids
...


SC24a: Addition Polymerisation
=Process of many monomers joining together
Polymer=Large molecule made from lots of small molecules (monomers) joined together

Eg, polyethene (made from ethene)
-double covalent bond between
carbon atoms
-long lines are bonds that show the
connection with more monomers

-Equation? You add brackets and the n (how many repeating monomers

Naturally Occurring Polymers:
Starch: Polymer made from glucose
...

DNA: Polymer made from four different monomers (nucleotides)
...

Example: Carboxylic acid + Alcohol → Ester + Water
...


Esters:
-Functional group: -COO-

-Remove OH from COOH
and H from diol
-Put together what is left

-Have a fruity smell (found in fruits)
...

-Properties: Volatile (evaporate easily)
...


SC24d: Problems with polymers
Problems with Polymers
Environmental Issues:
-Landfill Disposal: Wastes valuable land, harms animal habitats, and polymers don’t biodegrade easily
...

Solutions:
-Reduce material use
...

-Recycle polymers into new products
...

3
...

5
...

Separate different types of polymers
...

Melt and remold or reprocess into new products
...

-Break down into carbon dioxide, water, and minerals via microorganisms
...


Reuse vs
...

-Recycling: Involves processing to create new materials but can be energy-intensive

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