Organic chemistry Flashcards
Hydrocarbon
Only contains Hydrogen and Carbon
Alkane
Contains only single bonds
CnH2n+2
Alkene
Contains at least one double bond
CnH2n
Saturated
Contains only single bonds
Unsaturated
Contains at least one double bond between carbon atoms
Parts of a name
- How many carbon atoms- meth, eth, prop, but
- Alkane or Alkene- ane or ene
Butane [3]
C4H10
Only single bonds
Alkane
Ethene [3]
C2H4
Contains a double bond
Alkene
of carbon atoms
Meth, eth, prop, but
Meth- 1
Eth- 2
Prop- 3
But- 4
Ethanol [2]
C2H6O or C2H5OH
Alcohol (contains OH)
Complete combustion
Enough oxygen
Products of complete combustion
Carbon dioxide + Water
CO2 + H2O
Fractional Distillation products
Fuel gases, petrol, kerosene, diesel, fuel oil, bitumen
Suggest 3 reasons why bitumen is not used as a fuel
[3]
- Too high a boiling point
- Not flammable
- Viscous (doesn’t flow easily)
How can bromine be used to distinguish between alkanes and alkenes? [2]
- Alkanes do not react with bromine (as they are saturated)
- Alkenes do react with bromine and the orange bromine with becoming discoloured (double bond opens and bonds with the bromine)
Ethene reaction with hydrogen.
[2]
- Forms ethane
- C2H4 + H2 –> C2H6
Ethene reaction with bromine
[2]
- Forms a haloalkane
- C2H4 + Br2 –> C2H4Br2
Ethene reaction with steam
{2}
- Forms ethanol (alcohol)
- C2h4 + H2O –> C2H5OH
What is an addition reaction? [1]
Give an example of one [1]
- A reaction where there are two reactants and then there is one product
- Ex. Propene + bromine –> Biopropane ( halo alkane)
Give 2 reasons why large hydrocarbon molecules are cracked to produce smaller hydrocarbon molecules
[2]
- There is a higher demand for smaller hydrocarbon molecules
- They are better fuels (easier burning)
Fuels
Release heat energy when they combust (burn in oxygen)
Symbol equation for cracking:
decane –> octane + ethene
C10H22 –> C8H18 + C2H4
Name 3 fossil fuels
Coal, natural gas, petroleum
What is meant by homologous series? [3]
A family of similar compounds.
The compounds in a homologous series have the same general formula and a gradual change in physical properties.
Each compound differs from the next by a CH2 group.
How many bonds can carbons form? [1]
4
Which type of bonds do alkanes form?
Single, covalent
Name the products of fractional distillation of petroleum [5]
Refinery gas- bottled gas for cooking and heating
Gasoline fraction- for fuel (petrol) in cars
Naphtha fraction- the feedstock for making chemicals
Diesel oil/gas oil- for fuel in diesel engines
Bitumen- for road surfaces
Name the 2 ways ethanol can be produced.
State an advantage and disadvantage for both. [6]
- Fermentation
+ cheap, made at 37 degrees c and so not much energy is used
- Low percentage yield, only about 18% yield of ethanol [3] - Ethene and steam reaction (hydration reaction)
+ Continuous process
+ High percentage yield
- Expensive, high temperature is needed and so uses a lot of electricity [3]
Define Polymers
long chain molecules formed
from small units (monomers)
What type of polymerisation is used in forming poly(ethene)?
Addition polymerisation
Name 2 things necessary when drawing polymers
- The bonds extend out of the square brackets
- Add the ‘n’ by the bottom right of the polymer and an ‘n’ on the left hand side of the displayed formula of the alkene
State the differences between addition polymerisation and condensation polymerisation. [2]
Addition polymerisation- multiple of the same monomer bonds to form 1 polymer. 2+ reactants and 1 product
Condensation polymerisation- 2 different monomers bond together with the removal of a small molecule (usually water) 2+ reactants and 2 products
