C3 - Organic Chemistry Flashcards
What is the general formula of an alcohol?
C and then subscript n
H and then subscript 2n + 1
Then OH
What is the functional group of alcohols?
-OH
What is the naming system for alcohols?
Replace the final “e” with “ol”
What would the chemical formula for propanol be?
C^3 H^7 OH
What are the 3 main chemical properties for most alcohols?
They burn in air to produce carbon dioxide and water
Dissolve completely in water to form neutral solutions
They react with sodium to give hydrogen and sodium ethoxide
What is the alcohol used in drinks and what is the problem with it?
Ethanol is used in drinks and it damages the liver and brain
How do you draw alcohols?
H H
| |
H - C - C - O - H
| |
H H
For ethanol etc.
The top and bottom H’s need to be moved one to the left
What other 2 things can alcohols be used for?
Solvent
Fuels
What is a solvent?
A chemical that can dissolve substances that water can’t dissolve
In what 2 contexts are alcohols used as solvents?
Ethanol is used as the solvent for perfumes and aftershave lotions
Methylated spirit is ethanol with other chemicals mixed with it and it’s used to clean paint brushes
In what 2 ways are alcohols used as fuels?
They are burned in spirit burners
They can be mixed with petrol for use in a car
What are the 4 advantages of using ethanol as a fuel?
No smell
Clean burning so no pollution
Some developing countries can ferment sugar from sugar canes to get ethanol
Sugar cane is a renewable source
How else can you produce alcohols?
An example would be ethene + water –> ethanol
What is the functional group of carboxylic acids?
-COOH
What is the naming system for carboxylic acids?
Replace the “e” with “oic acid”
How do you draw carboxylic acids?
H H O
| | //
H - C - C - C
| | \
H H OH
For propanoic acid
What is the general formula for a carboxylic acid?
C and then subscript n
H and then subscript 2n+1
Then COOH
What are the 3 main ways that carboxylic acids react?
Ethanoic (example) acid + metal carbonate –> metal ethanoate + carbon dioxide + water
Dissolves in water to ionise, release H+ ions and make the solution acidic
Carboxylic acid + alcohol –> ester + water
What is the problem with acidic solutions of carboxylic acids?
They are weak acids
How are carboxylic acids made?
An example is butanol + oxygen –> butanoic acid + water
What are the 5 uses of carboxylic acids?
Ethanoic acid can be dissolved in water to make vinegar
Citric acid is another carboxylic acid which is present in fruits
Soaps and detergents are made from carboxylic acids and long chain carbon atoms
Used to make eaters
Can be used as a solvent but it makes the solution acidic
What is the functional group of esters?
-COO-
What is the naming system for esters?
The alcohol forms the first part and the carboxylic acid forms the second part
An example is: for methane and propanoic acid, the ester is methyl propanoate
How are esters made?
Alcohol and carboxylic acids react in the presence of an acid catalyst (usually sulphuric) to form the ester and water
How do you draw esters?
H O
| //
H - C - C H H
| \ | |
H O - C - C - H
| |
H H
For ethyl ethanoate
The top left part is the carboxylic acid part and the bottom right is the alcohol
The top line has been shifted to the right
What is the main use of esters and why?
Used for flavourings and perfumes because they smell nice and are also volatile meaning that the evaporated molecules can be detected easily by smell receptors
What is the other main use of esters?
Solvents for paint, ink, glue etc.
What are the 4 disadvantages of esters?
Very flammable and this makes them dangerous
Don’t mix well with water and not very soluble
Some esters irritate mucous membranes in the nose and mouth
Some are toxic
