Functional Groups Flashcards
What is the functional group of alcohols?
-OH.
What is the general formula of alcohols?
Cn H2n+1 OH
What are the first three alcohols?
Methanol, ethanol and propanol.
What is a homologous series?
A group of chemicals that react in a similar way because they have the same functional group.
What do the first three alcohols burn in air to produce?
Carbon dioxide and water.
What do the first three alcohols dissolve in water to produce?
Neutral solutions.
What do the first three alcohols react with sodium to give?
Hydrogen and alkoxides.
What is the main alcohol in alcoholic drinks?
Ethanol.
Why are alcohols useful solvents?
They can dissolve most compounds that water can, and more.
What is the solvent in perfumes and aftershave lotions?
Ethanol.
What is methylated spirit used for?
- Cleaning paint brushes
2. Fuel
What is ethanol used as a fuel for?
- Spirit burners (clean, no odour)
2. Car fuel
Why is ethanol good as a car fuel?
- Clean burning, less pollution.
- Renewable
- Good for countries without oil
What functional group do carboxylic acids have?
-COOH.
What are the first three carboxylic acids?
Methanoic acid, ethanoic acid and propanoic acid.
What is the equation for the reaction between carboxylic acids and carbonates?
Carboxylic acid + Metal carbonate –> Carbon dioxide + Water + Metal carboxylic-anoate
e.g Ethanoic acid + Sodium carbonate –> Carbon dioxide + Water + Sodium ethanoate
Why don’t carboxylic acids form strong acidic solutions?
They don’t ionise completely, so not many H+ ions are released.
What is the strength of an acid dictated by?
How well it has ionised in water.
How can ethanoic acid be made?
By oxidising ethanol.
What is the equation for the oxidisation of ethanol?
Ethanol + Oxygen –> Ethanoic acid + Water
How can ethanoic acid be fermented?
- Yeast
2. Oxidising agents
What can ethanoic acid be used for?
Dissolved in water to make vinegar.
What can citric acid be used for?
- Fizzy drinks
2. Removing scale
What are carboxylic acids used for?
- Soaps and detergents (long chain)
2. Preparation of esters
Why isn’t ethanoic acid usually chosen as a solvent?
It makes the solution acidic.
What are esters formed from?
An alcohol and a carboxylic acid.
What is the equation for the formation of esters?
Alcohol + Carboxylic acid –> Ester + Water
What kind of catalyst is used in the formation of esters?
Acid catalyst e.g concentrated sulfuric acid
What property of esters makes them good for what purpose?
Esters are volatile so they’re good for perfumes, flavourings and aromas.
What are the problems with esters?
- Flammable
- Don’t mix well with water
- Inhaling the fumes irritates mucous membranes
- Can be toxic
What do esters mix with?
Alcohols and organic solvents.
What are esters used for?
- Solvents for paint, ink, glue and nail varnish remover
- Ointments
- Perfumes, flavourings etc.
Why can esters result in flash fires?
They’re heavier than air and flammable.
