Organic Chemistry Flashcards
What is organic chemistry
the study of compounds with C-H bonds
Why can carbon form many compounds? (3)
- a carbon can form bonds with other carbon atoms to make chains and rings
- a carbon atom can form a single or double bond to other carbons
- a carbon atom can bond with other atoms (eg. hydrogen)
How many bonds can carbon form?
4 covalent bonds
What is a homologous series?
Where all the carbon compounds have the same general formula
How many carbon atoms are in the prefix “meth”?
1
How many carbon atoms are in the prefix “eth”?
2
How many carbon atoms are in the prefix “prop”?
3
How many carbon atoms are in the prefix “but”?
4
What is the suffix for alkanes?
ane
What is the suffix for alkenes?
ene
What is the suffix for alcohols?
anol
What is the suffix for carboxylic acids?
Anoic acid
What are hydrocarbons?
A molecule only consisting of carbon and hydrogen
What is a functional group?
A reactive group in a molecule
Do alkanes have functional groups?
No
What is combustion?
The reaction of fuels with oxygen, forming oxides and releasing thermal energy
What are alkanes?
Saturated hydrocarbons
Under what conditions does complete combustion occur?
What colour is the flame?
if there is a plentiful supply of oxygen in the air.
an orange flame is produced, and more carbon means a more orange flame
Under what conditions does incomplete combustion occur?
What does it form
If there is a limited supply of oxygen
It produces carbon monoxide and water (and possibly soot)
What is formed by the complete combustion of hydrocarbons?
Carbon dioxide and water vapour
How does carbon dioxide affect the environment?
Contributes to green house effect
Leading to:
- rise in sea level
- flooding
- climate change
What is formed by incomplete combustion of fuels
Carbon monoxide, water and sometimes soot
What is the impact of carbon monoxide?
binds to haemoglobin in the blood, reducing its capacity to carry oxygen
(Toxic gas)
How is soot formed?
Incomplete combustion of fuels
What is the impact of soot?
Pollutes the air and causes lung damage and respiratory problems
Give a balanced symbol equation for the combustion of sulphur
S2 + 2O2 —> 2SO2
Give a balanced symbol equation for the reactions which result in acid rain
- S2 + 2O2 —> 2SO2
- SO2 + H2O —> H2SO3
What is the effect of acid rain? (3)
- Damage buildings (especially limestone buildings),
- damage vegetation
- kill fish.
How can you prevent acid rain? (2)
- By removing sulphur impurity from coal
- or passing it through an alkali
What is the general formula for Alkenes
CnH2n
Do Alkenes have a functional group?
Yes, they have a double carbon bond
What is an addition reaction?
Where two molecules react to form one product
What is a polymer?
A long chain molecule made from joining small molecules together
What are monomers?
A small molecule that combines with other monomers to make a polymer
What is addition polymerisation? (2)
- The process of joining monomer molecules together
- to form a long chain molecule
what is a non-biodegradable material?
When a material can’t be decomposed by natural bacteria
What two methods are used to dispose of polymers?
- landfill
- incineration
What is the general formula for alcohols?
CnH2n+1OH
What is the functional group for alcohols?
Hydroxyl group (-OH)
What is the colour and state of all alcohols?
Colourless liquid
What is the result of complete combustion of alcohols?
- carbon dioxide and water
- clean blue flame with an orange tip
What is the result of incomplete combustion of alcohols?
- carbon monoxide, soot and water
- Smokey blue flame with orange tip
What is the product of oxidation of ethanol
Ethanoic acid (acid in vinegar)
What is the general product of oxidation of propan-1-ol, methanol and ethanol
What is different about the product for propan-2-ol?
- Carboxylic acids
- not in the case of propan-2-ol
Name the reagent used to convert propan-1-ol to propanoic acid
What colour change is observed?
What type of reaction is this?
- warm acidified potassium dichromate
- orange to green
- oxidation
What is fermentation?
The breakdown of sugars to produce ethanol and carbon dioxide
What are the conditions required for fermentation? (4)
- sugars dissolved in solution
- in the presence of yeast
- at a warm temp (not above 37º)
- in the absence of air (anaerobic)
How are higher concentrations of ethanol produced?
Fractional distillation
How long does fermentation take?
Several days
What concentration is produced by fermentation?
12-15%
Other than fermentation, how else can you produce ethanol?
Reacting ethene with steam
What is the functional group for carboxylic acids?
Carboxyl (-COOH)
Why are carboxylic acids not hydrocarbons?
They contain oxygen, not just hydrogen and carbon
What is the colour and state of all carboxylic acids?
Colourless liquid
Give the word equation for the reaction used to test for carboxylic acids
Carbonate + acid —> salt + water + carbon dioxide
What is the molecular formula of methane
CH4
What is the molecular formula of ethane
C2H6
What is the molecular formula of propane
C3H8
What is the molecular formula of butane
C4H10
What is the colour and state of alkanes at room pressure and temperature
Colourless gas
What is the molecular formula of ethene
C2H4
What is the molecular formula of propene
C3H6
What is the molecular formula of but-1-ene
C4H8
What is the molecular formula of but-2-ene
C4H8
What is the colour and state of alkenes at room pressure and temperature
Colourless gas
What is the molecular formula of methanol
CH3OH
What is the molecular formula of ethanol
C2H5OH
What is the molecular formula of propan-1-ol
C3H7OH
What is the molecular formula of propan-2-ol
C3H7OH
What is the viscosity of a substance?
a measure of a fluid’s resistance to flow
What is the observation when an Alkene reacts with bromine?
When is this reaction used?
- yellow-orange liquid turns colourless
- to test for a double carbon bond in an alkene
What is the product formed in a reaction between an alkene and hydrogen?
An alkane
What is the catalyst for the addition reaction between ethene and hydrogen?
What condition is required for this reaction?
- Finely divided nickel
- 150°C
What is the product of the addition reaction between an alkene and steam?
An alcohol
What does saturated mean in organic chemistry?
Where all carbon-carbon covalent bonds are single
What does unsaturated mean in organic chemistry?
When a molecule contains one or more carbon-carbon double bonds
What is an addition reaction?
A reaction where 2 molecules react to form 1 product
What is a hydration reaction?
When water is added across a C=C double bond
What other name is given to the addition reaction between alkenes and hydrogen?
What does this mean?
- Hydrogenation
- hydrogen is added across the C=C double bond
What is the catalyst for the addition reaction between ethene and water?
What condition is required for this reaction?
- concentrated phosphoric acid
- high temp (steam)
What is the name is given to molecules like but-1-ene and but-2-ene?
How do they differ?
- isomers
- differ by position of their functional group e.g C=C double bond in moleule (but-1-ene or 2) or OH (propan-1-ol or 2)
What is the molecular formula of methanoic acid?
HCOOH
What is the molecular formula of ethanoic acid?
CH3COOH
What is the molecular formula of propanoic acid?
C2H5COOH
What is the molecular formula of butanoic acid?
C3H7COOH
Why does melting and boiling point increase as the size of the molecule increases in each homologous group?
More van der walls forces - more energy required to overcome the forces
What are the properties of a homologous series? (4)
- same general formula
- differ by a CH2 unit
- gradation in physical properties
- similar chemical properties
Which homologous group doesn’t have a functional group?
Alkanes
What are the physical properties affected by size of chains in homologous series? (3)
bigger the chains:
- greater viscosity
- darker colour
- higher m.p. And b.p.
How is crude oil separated?
Explain
(3)
- Fractional distillation
- crude oil is heated and vapourised
- separated in terms of b.p. (higher b.p., lower fraction)
What are the fractions of crude oil
and
what are their uses?
(6)
- refinery gases - bottled gases
- petrol - fuel for cars
- naptha - manufacture of chemicals and plastics
- kerosine - fuel for aircrafts
- diesel - fuel for cars and trains
- bitumen - surface roads and roofs
What is cracking? (2)
- the breakdown of larger saturated hydrocarbons (alkanes)
- into smaller more useful ones, some of which are unsaturated (alkenes)
Describe the appearance of sulphur
What colour is the flame when sulphur burns in air?
- Yellow solid
- blue
What colour is bromine water?
Yellow-orange
Name the alkene from which PVC is formed
Chloroethene / vinyl chloride
Give a balanced symbol equation for the reaction between ethene and bromine
C2H4 + Br2 —> C2H4Br2
How do you produce a carboxylic acid from an alcohol?
What is released?
- React it with oxygen (oxidation)
- Hydrogen gas