Hydrocarbons & Cracking Flashcards
What is a hydrocarbon?
A compound that only contains hydrogen and carbon atoms.
What is crude oil?
Mixture of hydrocarbons formed over millions of years from remains of dead aquatic organisms.
Carbon atoms in hydrocarbons are joined together in:
1.
2.
Chains.
Rings.
Crude oil is an important source for what 5 things:
1.
2.
3.
4.
5.
- Fuel.
- Feedstock.
- Lubricants.
- Detergents.
- Solvents.
What is feedstock?
(Note: made from alkenes).
A raw material used to provide reactants for an industrial reaction.
What is a petrochemical?
A substance made from crude oil using chemical reactions.
An example of feedstock: Ethene.
Ethene is produced from crude oil. It is used as feedstock to make poly(ethene), a ____________.
polymer
Alkanes form a homologous series.
What is a homologous series?
A family of organic compounds that have the same functional group and chemical properties.
Like all homologous series, alkanes:
Have the same __________________.
Differ by ______ in molecular formulae from each compound.
Show a gradual variation in physical properties, such as their ___________________.
Have similar ____________________.
general formula
CH2
boiling points
chemical properties
What is the general formula for alkanes?
CnH2n+2
What are the names of the first 4 alkanes in order:
1.
2.
3.
4.
1.Methane.
2. Ethane.
3. Propane.
4. Butane.
Ball and stick models show that the _________________ are not really at angles of ____° like in the structural formulas.
covalent bonds
90
Alkanes are _____________ hydrocarbons because their _______________ are joined by C-C _________________.
saturated
carbon atoms
single bonds
Different hydrocarbons have _______________________.
different boiling points
What is are fractions?
The different parts of the original crude oil mixture.
What is fractional distillation?
When a mixture of several substances is distilled.
And the evaporated components are collected as they condense at different temperatures.
Heated crude oil enters a ___________________, which is _____ at the bottom and gets ____________ towards the top.
___________ from the crude oil _______ through the column.
Vapours __________________________ that are led out of the column at ___________________.
fractionating column
hot
cooler
Vapours
rise
cool and condense into liquids
different heights
Small hydrocarbon molecules have ____________________________, so they have ______________________.
They do not _____________, so they leave the column as ________.
weak intermolecular forces
low boiling points
condense
gases
Long hydrocarbon molecules have _____________________________, so they have ___________________.
They leave the column as _____________________.
stronger intermolecular forces
high boiling points
hot liquid bitumen
What are 4 properties of small molecules at the top of the fractioning column:
1.
2.
3.
4.
- Low boiling point.
- Very volatile.
- Ignites easily.
- Flows easily.
What are 4 properties of large molecules at the bottom of the fractioning column:
1.
2.
3.
4.
- High boiling point.
- Not volatile.
- Does not ignite easily.
- Does not flow easily.
What are the order of products from fractional distillation from top to bottom:
(Lazy Penguins Keep Drinking Hot Beverages).
Liquified petroleum gases.
Petrol.
Kerosene.
Diesel.
Heavy fuel oil.
Bitumen.
What are the 4 similar properties of hydrocarbons (mostly alkanes) in a fraction?
Numbers of hydrogen and carbon atoms.
Boiling points.
Ease of ignition.
Viscosity.
The hydrocarbons in different fractions have __________________________.
different properties
What is cracking?
(For most hydrocarbon molecules).
A reaction where larger, saturated hydrocarbon molecules are broken down into smaller, unsaturated hydrocarbons.
What is the reactant for cracking?
What are the products of cracking?
Reactants: Alkane.
Products: Alkanes and alkenes.
What is an alkane?
A saturated hydrocarbon.
An alkane is a compound of what?
Hydrogen and carbon only.
Alkenes are joined by ___-___ single bonds
C-C
What is an alkene?
An unsaturated hydrocarbon.
An alkene are compounds of what?
Hydrogen and carbon.
Carbon and carbon.
Alkenes have at least one __=__ double bond
C=C
What is the formula for an alkene?
CnH2n
True or false: Alkenes are less reactive than alkanes
False. Alkenes are more reactive than alkanes.
What is catalytic cracking?
Using a temperature of approximately ______ °C and a _______________ known as a __________ which contains aluminium oxide and silicon oxide.
550
catalyst
zeolite
What is steam cracking?
Using a temperature of approximately _____ °C with no ____________.
850
catalyst
Cracking helps to match the demand of certain ______________ with matching ____________.
fractions
supply
Fractional distillation of crude oil produces more ___________________________ than can be sold, and less of the _____________________________________.
larger hydrocarbons
smaller hydrocarbons in demand
How do you test for a double C=C bond (alkene) in a molecule?
React with bromine water and if an alkene is present it will turn from orange to colourless.
