3.6 Alcohols, carboxylic acids and esters Flashcards
How are carboxylic acids formed?
By the oxidisation of alcohols
What are the two ways that alcohols can be oxidised?
- Through microbial action
2. Reacting with a chemical oxidising agent
What is an example of a chemical oxidising agent?
Potassium Dichromate
What acid is the main part of vinegar?
Ethanoic acid
What sort of pH do carboxylic acids have and why?
High pH values for acids. This is because the only partially ionise.
What substance is formed by the oxidisation of ethanol?
Ethanoic acid
Why does the fermentation of beer and wine have to take place in the absence of air?
The oxygen in air would react with the acids to cause a carboxylic acid to form.
What is the formula of methanoic acid?
HCOOH
What is the formula of ethanoic acid?
CH3COOH
What is the formula of propanoic acid?
C2H5COOH
What does ethanoic acid smell of?
Vinegar
What colour does universal indicator paper go when dipped in ethanoic acid?
Orange
What is a carboxylic acid?
A weak acid that only partially ionises in a solution
What pH do alcohols have when dissolved in water and why?
A neutral pH, because they can’t gain or lose hydroxide (OH) ions
What happens when you add sodium to alcohols?
Effervescence as hydrogen is being given off. This can be tested with the squeaky pop.
What solvents are alcohols used for?
Medicines, perfume and cosmetics
Why are alcohols good solvents in perfume?
Because they evaporate quickly from the skin
Do alcohols burn well in air?
Yes they burn well in air in a combustion reaction
What is the reaction when alcohols combust?
Alcohol + oxygen —-> carbon dioxide + water
Are alcohols dangerous?
Ethanol is toxic in large amounts but others are even more dangerous; they can cause death in small amounts
What are the advantages of using alcohols as fuels?
They’re renewable and carbon neutral
What are two examples of alcoholic fuels?
Methylated spirit is used in camping stoves
Ethanol is used as car fuel
What is the general formula for alcohols?
CnH2n+1OH
What is the functional group for alcohols?
-OH
What series do the different alcohols form together?
A homologous series
Name the first three alcohols in order of increasing number of carbon atoms
Methanol
Ethanol
Propanol
What do the names of all alcohols end with?
-ok
What kind of compounds are alcohols?
Organic compounds
Which alcohol does alcoholic drinks contain?
Ethanol
What is the formula for methanol?
CH3OH
What is the formula for ethanol?
C2H5OH
What is the formula for propanol?
C3H7OH
What colour are the simplest alcohol liquids?
Colourless
What are alcohols good solvents?
Because they dissolve some substances that water doesn’t
What colour flames do alcohols burn with?
Pale blue flames
