Organic chemistry Definitions/Details Flashcards
Homologous series
a family of similar compounds with similar chemical properties due to the presence of the same functional group
Saturated compound
A compound that has molecules in which all carbon-carbon bonds are single bonds
Unsaturated compound
A compound that has molecules in which one or more carbon-carbon bonds are not single bonds
Functional group
an atom or group of atoms that determine the chemical properties of a homologous series
Structural isomers
Compounds with the same molecular formula, but different structural formulae
Structural formula
an ambiguous description of the way the atoms in a molecule are arranged
General formula of alkanes
CₙH₂ₙ₊₂
General formula of alkenes
CₙH₂ₙ
General formula of alcohols
CₙH₂ₙ₊₁OH
General formula of carboxylic acids
CₙH₂ₙ₊₁COOH
General characteristics of a homologous series
-Having the same functional group
-Having the same general formula
-Differing from one member to the next by a -CH₂- unit
-Displaying a trend in physical properties
-Sharing similar chemical properties
The bonding in alkanes is…
single covalent
Alkanes are…
saturated hydrocarbons
In terms of reactivity, alkanes are…
generally unreactive, except in terms of combustion and substitution by chlorine
What happens in a substitution reaction
One atom or group of atoms is replaced by another atom or group of atoms
Features of the substitution reaction of alkanes with chlorine
-A photochemical reaction(occurs as a result of light energy)
-Ultraviolet light provides the activation energy
The suffix -ane refers to…
alkanes
The suffix -ene refers to…
alkenes
The suffix -ol refers to…
alcohols
The suffix -oic acid refers to…
carboxylic acids
The prefix meth- means that…
there is 1 carbon atom
The prefix eth- means that…
there are 2 carbon atoms
The prefix prop- means that…
there are 3 carbon atoms
The prefix but- means that…
there are 4 carbon atoms
The prefix pent- means that…
there are 5 carbon atoms
The prefix hex- means that…
there are 6 carbon atoms
The bonding in alkenes includes a…
double carbon-carbon covalent bond
Alkenes are…
unsaturated hydrocarbons
In an addition reaction…
an unsaturated alkene is turned into a saturated compound(only one product is formed)
Functional group of alkenes
C=C
How alkenes are made
By cracking alkanes(using a high temperature and a catalyst)
Why alkenes are much more reactive than alkanes
The double bond in alkenes can break to add on other atoms
Addition polymerisation
an addition reaction in which alkene molecules(monomers) add on to each other to form compounds with much longer carbon chains(polymers)
Test for unsaturation
-Add bromine water(which is orange) to a compound
-If a C=C bond is present in that compound, the solution becomes colourless
Reactions between hydrogen and alkenes will produce…
alkanes
Conditions required for reactions between hydrogen and alkenes
-Temperature: 150°C
-Catalyst: nickel catalyst
Hydration reaction
a chemical reaction in which a substance reacts with water
What happens when alkenes react with steam
Alcohols are formed
Conditions required for reactions between steam and alkenes
-Temperature: 300°C
-Pressure: 60atm
-Catalyst: (phosphoric)acid catalyst
Complete combustion of alkanes
The alkane and oxygen react together to form carbon dioxide and water
Incomplete combustion of alkanes
The alkane and oxygen react together to form carbon monoxide and water
Functional group of alcohols
OH
Uses of ethanol
-Is a good solvent(dissolves many substances that don’t dissolve in water)
-Is used as a fuel
Combustion of ethanol
Ethanol reacts with oxygen to form carbon dioxide and water
Conditions required for the fermentation of aqueous glucose(to form ethanol)
-Temperature: 25-35°C
-In the presence of yeast
-Catalyst: yeast enzymes
-In the absence of oxygen
Conditions required for the hydration of ethene
-Temperature: 300°C
-Pressure: 60atm
-Catalyst: (Phosphoric)acid catalyst
Advantages of the manufacture of ethanol by fermentation
-Renewable(uses plants)
-Uses less energy(lower temperature and pressure)
Disadvantages of the manufacture of ethanol by fermentation
-Produces carbon dioxide as waste
-Slow process
Advantages of the manufacture of ethanol by the hydration of ethene
-No waste products
-Produces ethanol continuously
-Quicker process
Disadvantages of the manufacture of ethanol by the hydration of ethene
-Requires a lot of energy(high heat and pressures)
-Use of crude oil which is non-renewable
Functional group of carboxylic acids
COOH
In terms of acidity, all carboxylic acids are…
weak acids
Carboxylic acids are made by…
oxidising alcohols
Process of fermentation of ethanol
When ethanol is left in presence of oxygen(eg. in open air), bacteria will bring about its oxidation to ethanoic acid
Process of oxidation via acidified potassium
manganate(VII)
When ethanol is heated with the oxidising agent acidified potassium manganate(VII), ethanoic acid is formed
What happens when a carboxylic acid reacts with an alcohol
An ester and water is formed
Reactions between carboxylic acids and alcohols are…
-reversible
-condensation reactions
Condensation reaction
a chemical reaction in which two molecules are combined to form a single molecule with the loss of a small molecule (e.g. water)
In an ester, the alcohol part comes…
first in the name but second in the formula
Catalyst for reactions between carboxylic acids and alcohols
Concentrated sulfuric acid
Fossil fuels
-Coal
-Natural gas
-Petroleum
Main constituent of natural gas
Methane
Hydrocarbons
compounds that contain hydrogen and carbon only
Petroleum is a…
mixture of hydrocarbons
Use of refinery gas fraction
Used in heating and cooking
Use of gasoline/petrol fraction
Fuel used in cars
Use of naptha fraction
Chemical feedstock(source for making other chemicals)
Use of kerosene/paraffin fraction
Jet fuel
Use of diesel oil/gas oil fraction
Fuel used in diesel engines
Use of fuel oil fraction
Fuel used in ships and home heating systems
Use of lubricating oil fraction
Lubricants, waxes and polishes
Use of bitumen fraction
Making roads
How properties of fractions obtained from petroleum change from the bottom to the top
-Decreasing chain length
-Higher volatility
-Lower boiling points
-Lower viscosity
Polymers
large molecules built up from small molecules(called monomers)
What plastics are made from
Polymers
Environmental challenges caused by plastics
-Disposal in land fill sites
-Accumulation in oceans
-Formation of toxic gases from burning
Why plastics are hard to dispose of
-Plastics are made from polymers
-Polymers are non-biodegradable(they don’t decay)
-Burning them isn’t good as poisonous gases form as a result
Proteins
natural polyamides
Features of PET
Can be converted back to monomers and re-polymerised
Difference between addition and condensation polymerisation
-There are no additional products made apart from the polymer in addition reaction
-A small molecule(eg. water) is also formed along with the polymer in a condensation reaction