Topic 5 - Organic chemistry Flashcards
What is a homologous series?
Have same general formula
show a gradual increase in boiling point as it gets bigger
similar chemical properties as they contain the same functional group
each member differs from next by CH2
Whats the general formula for alkanes
CnH2n+2
What is the general formula for alkenes
CnH2n
What is the functional group of alcohol
OH
How do you name alcohols?
same as alkanes but replace final e with oh
What is the general formula of alcohols?
CnH2n+1OH
What is the general formula of carboxylic acids?
CnH2n+1COOH
How do you name carboxylic acids
meth/eth/prop… -anoic acid
What is the functional group of carboxylic acids
-COOH
What are the two ways to produce ethanol
fermentation of sugar
hydration of ethene
How do you produce ethanol by fermetation
mix yeast solution of a carbohydrate (e.g. glucose) seal and leave in warm place (between 30 and 40*C) as fermentatuion happens fastest between these temperatures.
Anaerobic conditions because oxygen converts te ethanol to ethanoic acid
makes 15% alcohol
Have to purify by fractional distilation to get stronger concentration
what is the equation of fermentation of sugar
glucose sugar yeast> ethanol + carbondioxide
C6H12O6 -> 2C2H5OH + 2CO2
What are the advatages and disadvantages of fermentation
+ made from renewable source
+ biofuels
+ can be frastional distilated to get 95%
+ countries with no oil but good weather for growing crops can use it
- Need good climate to grow sugar cane
- only 15%
- expensive to concentrate and purify ethanol
How do you produce ethanol by hydration of ethene
ethen made by craking crude oil fractions
will react with steam to make ethanol
high temp
catalyst used
no waste products
100%
What is the equation of hydration of ethene
Ethene + steam <u>Catalyst</u>> ethanol
C2H4 + H2O -> C2H5OH
What are the negative effects of alcohol
makes people less inhibited
reduces activity of the nervous system. increased reaction times, impared judgment, poor balance and coordination, uncontious and sometimes coma
causes dehydration which can damage brain cells which can lead to noticable frop in brain function and lead to long term memory loss
Liver disease
can lead to violent behaviour
can become addicted (alcoholism) which can lead to problems with other people and losing jobs
drink driving
expensive becuase of the need of police and doctors
what does dehydration of ethanol produce
ethene and water (waste product)
Ethanol -> ethene + water
C2H5OH -> C2H4 + H20
What catalyst is used in dehydration of ethene
hot aluminium oxide
What does hydration of ethanol produce
Ethanol + oxygen -> ethanoic acid + water
C2H5OH + O2 -> CH3COOH + H2O
What is a more common name for ethanoic acid
Vinegar
What are the uses for ethanoic acid (vinegar)
Flavouring
preserving foods
How do carboxylic acids react with metal
produce hydrogen and a salt ( metal _anoate)
How do carboxylic acids react with bases
produce water and a salt (E.g sodium ethanoate)
How do carboxylic acids react with carbonates
produce carbon dioxide, water, and salt (e.g sodium ethanoate)
give the symbol of sodium ethanoate
CH3COONa
What is the functional group of esters?
-COO-
How are esters fromed
when an alcohol reacts with a carboxylic acid.
An acid catylist is usually used (e.g concentrated sulfuric acid)
Alcohol + carboxylix acid -> ester + water
E.g ethyl ethanoate is made by reacting ethanol with ethanoic acid
what is the displayed, strucural, and molecula formula of ethanol reacting with ethanoic acid?
What are esters used in?
Perfumes
flavourings
fabrics (polyesters
plastics (polyesters)
How are soaps made?
When an ester reacts with an alkali.
fats or oils can be boiled with concentrated alkali solution to make soap.
The oil/fat breaks down glycerol and long chain carboxylic acids and the carboxylic acids then react with the alkali
A: Hydrophilic head loves water, dissolves in water (and not oil and fat). This part usually small and ionic
B: Hydrophobic tail hates water, is attracted to grease. Usually long hydrocarbon chain
How does soap work
Soap anions surround the oil blob and lift it away from the fabric
Why are vegetable oils hydrogenated for the food industry
Unsaturated oils are less viscous than saturated oils
How are unsaturated oils changed into solid saturated oils
by breaking the double bonds and adding hydrogen.
A nickel catalyst is used. (catalytic hyddrogenation)
the oil is filtered to remove the nickel and cooled to turn it into a solid fat
how are polyunsaturated vegatable oils used
hydrogenated to make margarine
not all double bonds in oil hydrogenated so some still unsaturated, firm enough to spread but lower in saturates than butter
