alcohols + CARBOXYLIC ACIDS + ester Flashcards
describe the main uses of alcohols
used as fuels, solvents, alcoholic drinks
draw the displayed formula of the first four alcohols
name four alcohols
write out structural formula
https://bam.files.bbci.co.uk/bam/live/content/z3j94qt/medium
just adding 1 carbon and 2 hydrogen each time
general formula CnH2n+1OH
describe how ethanol is produced
HYDRATION OF ETHENE - ETHENE + WATER (STEAM) -> (reversible) ethanol
Fermentation
Describe how ethanol is produced by fermentation
In fermentation, a sugar solution such as glucose is mixed with yeast.
The yeast converts the sugar solution to an aqueous solution of ethanol. Carbon dioxide gas is also produced
yeast sugar -----------------> ethanol + carbon dioxide
30degrees
The temperature should be around 30 degrees celcius
The reaction must take place in anaerobic conditions (without oxygen)
An advantage of making ethanol by hydrating ethene
The reaction produces a high yield of ethanol
A disadvantage of making ethanol by hydrating ethene
the reaction requires a high temperature - this will require a lot of energy
The ethene for this reaction comes from crude oil and is non-renewable
function group of alcohol
ALCOHOLS ARE A HOMOLOGOUS SERIES
-OH
general formula OF ALCOHOLS
CnH2n+1OH
Advantages of producing ethanol by fermentation
The low temperature means that the reaction does not require a lot of energy
The sugar for this reaction comes from plants and is therefore renewable
Aqueous solutions of ethanol are produced when sugar solutions
are fermented using yeast
disadvantages of producing ethanol by fermentation
Aqueous solutions of ethanol are produced when sugar solutions
are fermented using yeast
The product is an aqueous solution of ethanol (ethanol dissolved in water)
We then need to purify the ethanol by distillation and that requires energy
describe the solubility of alcohols in water
Alcohols are soluble in water and form neutral solutions
As the number of carbon atoms increases, the solubility of the alcohol in water decreases
describe how the alcohols react with sodium
e.g. ethanol + sodium
ethanol + sodium —> sodium ethoxide + Hydrogen
C2H5OH + Na –> C2H5ONa + H2
In this reaction, we see bubbles of hydrogen gas being produced
We have made the product sodium ethoxide
methanol + sodium
ethanol + sodium
propanol + sodium
butanol + sodium
methanol + sodium –> sodium methoxide + hydrogen
ethanol + sodium —> sodium ethoxide + hydrogen
propanol + sodium —-> sodium propoxide + hydrogen
butanol + sodium —-> sodium butoxide + hydrogen
describe how the alcohols react with an oxidising agent
e.g. ethanol reacting with an oxidising agent
oxidising agent
ethanol ———————–> ethanoic acid + water
example of oxidising agent - acidified potassium dichromate
when alcohols react with oxidising agents, they produce carboxylic acids and water
methanol/ethanol/propanol/butanol reacting with an oxidising agent
oxidising agent
methanol —————> methanoic acid + water
oxidising agent ethanol---------------> ethanoic acid + water
oxidising agent propanol---------------> propanoic acid + water
oxidising agent butanol---------------> butanoic acid + water
balance equations for the combustion of alcohols (remember alcohols are normally used as fuels)
combustion of ethanol
describe what happens during the combustion of alcohols
alcohols are normally used as fuels)
Alcohols release energy when combusted
Combusting an alcohol in air produces carbon dioxide and water
C2H5OH + 3O2 —> 2CO2 + 3H2O
COMPLETE AND BALANCE THIS EQUATION
C4H9OH + O2 –> ________
C4H9OH + 6O2 —> 4CO2 + 5H2O
describe the structures of the first four carboxylic acids
a compound that contains the -COOH functional group
describe what happens when carboxylic acids dissolve in water
In water, carboxylic acids are weak acids
Because carboxylic acid only partially ionise in aqueous solutions, they are weak acids
Carboxylic acids have a higher pH than a strong acid such as hydrochloric acid
When carboxylic acids dissolve in water they ionise and release H+ ions resulting in an acidic solution
But becuase they do not ionise completely (not all the acid molecules release their H+ ions) , they just form weak acidic solutions
This means that they have a higher pH (are less acidic) than aqueous solutions of strong acids with the same concentration
https://encrypted-tbn0.gstatic.com/images?q=tbn:ANd9GcSJuSsVBUiT8GkWPUrKwxCstzGCzyV-rfUVguDEwfZEkRpygG_x
ethanoic acid(aq) ethanoate ion (aq) hydrogen (aq)
Ethanoic acid is ionising to produce the ethanoate ion and H+
write out the equation of ethanoic acid dissociating in water - ethanoic acid in aqueous solution
describe what is happening
https://encrypted-tbn0.gstatic.com/images?q=tbn:ANd9GcSJuSsVBUiT8GkWPUrKwxCstzGCzyV-rfUVguDEwfZEkRpygG_x
ethanoic acid(aq) ethanoate ion (aq) hydrogen (aq)
Ethanoic acid is ionising to produce the ethanoate ion and H+
This is a reversible reaction
That means that the ethanoate ion and H+ can recombine to form ethanoic acid
describe the reaction of carboxylic acids with metal carbonates
ethanoic acid reacting with sodium carbonate
We have made the salt sodium ethanoate and carbon dioxide gas.
We have also made water
ethanoic acid + sodium carbonate –> sodium ethanoate + carbon dioxide + water
2CH3COOH (aq)+ Na2CO3 (aq)–> 2CH2COO- Na+ (aq) + CO2 (g) + H2O(g)
propanoic acid + potassium carbonate
complete the reaction
identify the salt
propanoic acid + potassium carbonate –> potassium propanoate + carbon dioxide + water
salt - potassium propanoate
describe the reaction of carboxylic acids with an alcohol
When we react a carboxylic acid with an alcohol, we make a molecule called an ester. We also make water.
Explain uses of esters
Esters are useful molecules are they often have a pleasant smell
They are used a lot in foods
carboxylic acid functional group
–COOH
first four carboxylic acids
draw their displayed formula
write out their structural formulas
https://bam.files.bbci.co.uk/bam/live/content/zq8y8mn/medium
c=o and c-oh can be at right angles
write out reaction of ethanoic acid and ethanol
ethanoic acid + ethanol —> ethyl ethanoate
reversible reaction - sulfuric acid catalyst
This reaction requires concentrated sulfuric acid as a catalyst
This is a reversible reaction
We have made the ester ethyl ethanoate
https://bam.files.bbci.co.uk/bam/live/content/zhvw6sg/medium
https://bam.files.bbci.co.uk/bam/live/content/zf8pb9q/medium
you name the alcohol first then the acid
conditions for reaction of ethanoic acid and ethanol
This reaction requires sulfuric acid as a catalyst
ester functional group
-COO
Name all the homologous series
Alkanes
Alkenes
Alcohols
Carboxylic Acids
Esters
