Organic Chemistry Flashcards
Alkanes general formula
CnH2n+2
Alkene general formula
CnH2n
Alcohols general formula
CnH2n+1OH
what is a functional group
an atom or group of atoms that determine the chemical properties of a homologous series
what are structural isomers
compounds with the same molecular formula, but different structural formulae, including:
C4H10 as CH3CH2CH2CH3 and CH3CH(CH3)CH3
what are hydrocarbons
compounds that contain hydrocarbon and carbon only
what is a structural formula
unambiguous description of the way the atoms in a molecule are arranged, including:
CH2=CH2, CH3CH2OH, CH3COOCH3
homologous series
a family of similiar compounds with similiar chemical properties due to the prescence of the same functional group
what does a saturated compound have?
has molecules in which all carbon-carbon bonds are single bonds, e.g. alkanes
What does an unsaturated compound have
Has molecules in which one or more carbon-carbon bonds are not single bonds
general characteristics of a homologous series as:
1) having the same functional group
2) having the same general formula
3) differing from one member to the next by a -CH2- unit
4) displaying a trend in physical properties
5) sharing similiar chemical properties
Fossil fuels
coal, natural gas and petroleum
main constituent of natural gas
Methane
what is petroleum
a mixture of hydrocarbons
describe the seperation of crude oil into useful fractions by fractional distillation
Evaporation of crude oil at high temperatures
Condensation at different fractions
Collection at fractions
Describe how the properties obtained from petroleum change from the bottom to the top of the fractionating column
1) decreasing chain length
2) higher volatility
3) lower boiling points
4) lower viscosity
Mnemonic to remember order of the fractional distillation of crude oil from smallest number of carbon to highest.
Red Pandas Nag Kittens Dancing Like Fighting Bats
Refinery gas, Petrol, Naptha, Kerosine, Diesel fuel, lubricating oil, fuel oil, bitumen
uses of refinary gas fraction
used in heating and cooking
uses of gasoline/petrol fraction
for car fuel
uses of kerosene/paraffin fraction
for jet fuel
uses of naphtha fraction
a chemical feedstock
uses of diesel oil/gas oil fractions
for fuel used in diesel engines
uses of fuel oil fraction
for fuel used in ships and home heating systems
uses of lubricating oil fraction
for lubricants, waxes and polishes
uses of bitumen fraction
making roads
describe the bonding in alkanes
single covalent and are saturated hydrocarbons
properties of alkanes
generally unreactive, except in terms of combustion and substitution by chlorine
what type of reaction is the substitution reaction of alkanes with chlorine
photochemical reaction, with ultraviolet light providing the activation energy
what happens in a substitution reaction
one atom or a group of atoms is replaced by another atom or group of atoms
describe bonding of alkenes
double carbon-carbon covalent bond and unsaturated hydrocarbon
manufacture of alkenes and hydrogen
the cracking of larger alkane molecules using a high temperature and a catalyst
reasons for the cracking of larger alkane molecules
-it helps to match the supply of fractions with the demand for them
- it produces alkenes, which are useful as feedstock for the petrochemical industry
test to distinguish between saturated and unsaturated hydrocarbons
Bromination - adding aqueous bromine
Adding bromine to unsaturated hydrocarbons go from an orange red to a colourless solution
how many products are formed in an addition reaction?
only one
Hydrogenation of alkene (adding hydrogen)
E.g. C2H4 + H2 –> C2H6
From alkene to alkane
From double bond to single bond
- requires nickel as catalyst
- occurs at 150C
Bromination of alkenes (adding bromine)
E.g. C2H4 + Br2 –> C2H4Br2
Ethene + bromine –> 1,2, -dibromoethane
From orange brown colour to colourless
Adding steam to alkenes
Hydration: C2H4 + H2O –> C2H5OH
(ethene + steam –> ethanol)
Double bond breaks and reacts with steam
Conditions: phosphoric acid (H3PO4) as catalyst, 300 - 400C, 60 - 70 atm
manufacture of ethanol
1) fermentation of aqueous glucose at 25-35C in the prescence of yeast and in the absence of oxygen
2) catalytic addition of steam to ethene at 300C and 6000kPa/60 atm in the prescence of an acid catalyst
complete combustion of ethanol
Forms carbon dioxide and water
C2H5OH + 3O2 –> 2CO2 + 3H2O
uses of ethanol
- fuel
- solvent
Advantages and disadvantages of the manufacture of ethanol by fermentation
advantages: simple equipment needed, uses renewable resources, low temperature required
disadvantages: batch process is inefficient, very slow ROR, produces dilute solution (further processing needed), carbon dioxide is produced (greenhouse gas)
Advantages and disadvantages of manufacture of ethanol by the catalytic addition of steam to ethene
Advantages: continuous process is efficient, fast ROR, produces pure ethanol, no greenhouse gas produced
Disadvantages: complex set up required, pollutants are formed from the burning of fossil fuels to maintain high temp, requires high temp and pressures (high cost)
Carboxylic acid + metals –>
salt + hydrogen
Carboxylic acids + carbonates –>
salt, water, and carbon dioxide gas
(neutralisation) carboxylic acid + base –>
salt + water
what are the endings of a salt formed by the reaction of carboxylic acids
-anoate
e.g. magnesium ethanoate
ethanoic acid + magnesium –>
magnesium ethanoate + hydrogen
(CH3COO)2Mg + H2
(neutralisation) propanic acid + potassium hydroxide –>
potassium propanoate + water
(CH3CH2COOK + H2O)
Describe the formation of ethanoic acid by the
oxidation of ethanol:
- with acidified aqueous potassium
manganate(VII) - by bacterial oxidation during vinegar
production
carboxylic acid + alcohol
ester + water
(using acid catalyst: sulfuric acid)
uses of ester
Perfume (has fruity smell)
how to name ester
alcohol-yl carboxylic -oate
e.g. ethyl propanoate
polymers
large molecules built by linking 50+ smaller molecules called monomers
formation of poly(ethene)
example of addition polymerisation using ethene monomers
what are plastics made from
polymers
