6B. Organic Chemistry 1 [SET 2] Flashcards
What is a hydrocarbon?
Molecule only contains hydrogen and carbons
Define homologous series
- same general formula
- SIMILAR CHEMICAL properties
- TREND in PHYSICAL properties
- same functional groups
Define functional group
The group of the molecule that determines which group the molecule is a member of and its physical and chemical properties
Give the suffixes for:
a) No double bonds
b) At least one double bond
c) An alcohol
d) An aldehyde
e) A ketone
f) A carboxylic acid
a) No double bonds -ane
b) At least one double bond -ene
c) An alcohol -ol
d) An aldehyde -al
e) A ketone -one
f) A carboxylic acid -oic acid
What does saturated mean?
Organic compounds which only contain single bonds
What are unsaturated compounds?
Organic compounds that contain at least one carbon carbon double covalent bond
Define structural isomerism
When molecules have the same molecular formula but different structural formula
What are the 3 ways in which structural isomers can be formed?
- Alkyl groups can be in different places
- Functional groups can be bonded to different parts
- There can be different functional groups
What are stereoisomers?
Organic compounds with the same molecular formula but have different arrangement of atoms in space
What is E-Z isomerism and how are E and Z isomers differentiated?
E-Z isomerism is caused by the limited rotation about C=C
double bonds. If the two substituents with the highest molecular mass are on the same side of the double bond, it is the Z (zusammen) isomer [zame zide].
If they are on different sides, it is the E (entgegen) isomer
What is Cis-trans isomerism?
Special type of E/Z isomerism where the two substituents on each carbon atom are the same
What is homolytic fission?
It happens when each bonding atom receives one electron from the bonded pair forming two radicals
What is heterolytic fission?
When one bonding atom receives both electrons from the bonded pair
What are radicals?
Highly reactive, neutral species
How is a covalent bond formed from two radicals?
The radicals collide and the electrons are involved the bond formation
Describe the process of fractional distillation of crude oil
- The oil is pre-heated then passed into a column.
- The fractions condense at different heights and the temperature of column decreases upwards
- The separation of the fuels depends on boiling point which depends on size of molecules. The larger the molecule the larger the London forces
- Similar molecules (size, bp, mass) condense together and so are collected at the same fraction
- Small molecules condense at the top at lower temperatures and big molecules condense at the bottom at higher temperatures.
What is the reforming of crude oil?
It is processing of straight-chain hydrocarbons into branched-chain alkanes and cyclic hydrocarbons for efficient combustion.
Describe the 𝜎 (sigma) bond in alkane
The sigma bond is a covalent bond which has a direct overlap of the s orbitals of the bonding atoms.
What reactions will alkanes undergo?
Combustion and reaction with halogens
What type of reaction is combustion?
Oxidation reaction
What is the colour of the bunsen burner flame during complete combustion?
Blue flame
Which type of hydrocarbon are most likely to undergo incomplete combustion?
Longer chains
What are the pollutants formed in the combustion of alkanes?
Carbon monoxide, oxides of nitrogen and sulfur, carbon particulates and unburned hydrocarbons
What is the environmental impact of carbon monoxide?
It is toxic/poisonous, binds to haemoglobin
What is the environmental impact of soot (carbon)?
Asthma, cancer, global dimming
What are the environmental impacts of nitrogen oxides?
NO is toxic and can form smog
NO 2 is toxic and acidic and forms acid rain
What are the environmental impacts of unbranched hydrocarbons?
They contribute towards formation of smog
What is the importance of catalytic converter?
These remove CO, oxides of nitrogen and
unburned hydrocarbons (e.g. octane,
C8H18) from the exhaust gases, turning
them into less toxic products CO 2 , N 2
and H 2 O.
What are biofuels?
They are fuels developed from renewable resources. Alcohols and biodiesel are two examples of renewable plant- based fuels
What are the advantages of biofuels?
- Reduces of use of non-renewable fossil fuels
- Use of biodiesel is more carbon-neutral
- Fossil fuels can be used feedstock for organic compounds
- Less large scale pollution
What are the disadvantages of biofuels?
- Less food crops may be grown because crops for biofuel would be grown instead
- Reduction of rain forests have to be cut down to provide land
- Shortage of fertile soils
How are halogenoalkanes formed from alkanes?
Radical substitution
In the presence of what does alkane react with halogens?
UV light
What are the three stages of free radical substitution?
Initiation - breaking halogen bond to form free radicals
Propagation - chain part of the reaction where products are formed but free radical remains
Termination - free radicals removed, stable products formed
What are the limitations of free radical substitution?
If there is excess halogen further substitution will take place therefore the desired product will be harder to separate from the others.
What is a 𝜋 bond?
Overlap of p orbitals sideways above and below the 𝜎 bond.
What are alkenes?
Unsaturated hydrocarbons that contain at least one C=C bond made up of a 𝜋 bond and a 𝜎 bond