Organic Chemistry Flashcards
How does fractional distillation work
The column is hot at the bottom and cool at the top so substances with high boiling points condense at the bottom and substances with lower boiling points condense on the way to stop
How do hydrocarbons properties change as you go up the fractionating column
- lower boiling points; less intermolecular bonds 2. lower viscosity as less molecules; less intermolecular bonds to tangle 3. less flammability; bigger hydrocarbons have more soot
Define a hydrocarbon
Hydrocarbon- a molecule that only contains hydrogen and carbon
What are the endings for Alkanes
‘ane’
What are the first 4 structural formulas for alkanes
- Methane CH4 - Ethane C2H6 - Propane C3H8 - Butane C4H10
What is the general formula for Alkenes
CnH2n+2
What is the difference between structural formulas, skeletal formula and strutured formulas
Structural is the pure numbers and elements Skeletal only use dots and sticks Strctures uses lines and elements
Define Isomers
Isomers have the same molecular formula but a different structure e.g. butane and methyl propane
How are isomers named
Largest carbon chain/ where functional groups are added
How is crude oil formed
Dead biomass formed thick layers of sediment on sea beds under heat and pressure in anaerobic conditions decay occurs; oil formed 50-250 million years
What are the conditions needed for formation of crude oil
-animal remains -high temp. and pressure -anaerobic conditions + millions of years
What sort of alkanes are in demand
Shorter alkanes are in very high demand and larger are less in demand as they are harder to ignite and more viscous
What is cracking
Larger alkanes are cracked to form alkanes and alkenes Long alkanes –> shorter alkanes + alkenes
What is catalytic cracking
vaporise alkanes and pass them over a hot catalyst; Al2O3 (600-700C)
What is steam cracking
you vaporise alkanes, mix them with steam and then heat to a high temp. Shown by bromine water going from orange to colourless
What are alkenes
a homologous series of unsaturated hydrocarbons with the functional group C=C double bond. End in ‘ene’
Why are Alkenes more reactive
due to the double bond
What is the General formula for Alkenes
CnH2n
Define unsaturated
Containing a c=c double bond
Define Saturated
Not containing a c=c double bond
Define polymerisation
when many small molecules (monomers) join to make very large molecules (polymers)
Define addition polymerisation
when 2 monomers join together, double bond breaks and 2 monomers join to from one polymer
What is the homologous series of alcohol
Compounds containing the functional group -OH and are named ‘ol’
What are the uses of alcohol
solvents and fuels dissolve in water to form neutral solutions Drinking
How is alcohol formed
1) Direct Hydration of Ethene 2) Fermentation of sugars
How do you test for alcohol
1) react with sodium to form ethoxides and hydrogen 2) dissolve in water to form neutral solutions and then test for pH
What are the equation and conditions for direct hydration of ethene
CH2,CH2 + H2O –> (conc. Phosphoric acid and steam high temp. + pressure) CH3,CH2,OH
What are the conditions for fermentation
- Sugars dissolved in water - Yeast is added - Mixture at 25-40 degrees Celsius for optimum temp. - Anaerobic conditions
What does mild oxidation of alcohols do
• Mild oxidation of alcohols makes a carboxylic acid
Define homogolous series
series of organic compounds with a similar general formula and also possess similar chemical properties due to the same functional group BUT have diff. physical properties
How is addition polymerisation shown
Define a carboxlyic acid
- Homologous series containing functional group -COOH and named ‘-oic acid’
Why are carboxylic acids weak
How do carboxylic acids react with metals
How do carboxylic acids form esters?
Carboxlic acids + alcohol ( sulphuric acid catalyst) —> esters and water
Define esters
group -COO- with a double bond on one oxygen
What are esters responsible for
smell of fruits and other extracts
Define Condensation Polymerisation
monomers with 2 diff functional groups joining to make a polymer and water is released
How are polyesters made
when molecules with 2 alcohol functional groups react with molecules with 2 carboxylic acid. The carboxylic acid groups react with alcohol groups to form ester linkages (-COO-) and give off water
Define polyamides
made when molecules with 2 functional groups of carboxylic acid react with 2 functional groups of amine. Amine functional groups is -NH2- . Carboxylic acid groups react with amine groups to form amine linkages (-CONH-) and give off water.
