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GCSE Chemistry > alcohols + CARBOXYLIC ACIDS + ester > Flashcards

alcohols + CARBOXYLIC ACIDS + ester Flashcards

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1
Q

describe the main uses of alcohols

A

used as fuels, solvents, alcoholic drinks

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2
Q

draw the displayed formula of the first four alcohols
name four alcohols
write out structural formula

A

https://bam.files.bbci.co.uk/bam/live/content/z3j94qt/medium

just adding 1 carbon and 2 hydrogen each time
general formula CnH2n+1OH

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3
Q

describe how ethanol is produced

A

HYDRATION OF ETHENE - ETHENE + WATER (STEAM) -> (reversible) ethanol
Fermentation

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4
Q

Describe how ethanol is produced by fermentation

A

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)

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5
Q

An advantage of making ethanol by hydrating ethene

A

The reaction produces a high yield of ethanol

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6
Q

A disadvantage of making ethanol by hydrating ethene

A

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

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7
Q

function group of alcohol

ALCOHOLS ARE A HOMOLOGOUS SERIES

A

-OH

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8
Q

general formula OF ALCOHOLS

A

CnH2n+1OH

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9
Q

Advantages of producing ethanol by fermentation

A

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

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10
Q

disadvantages of producing ethanol by fermentation

A

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

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11
Q

describe the solubility of alcohols in water

A

Alcohols are soluble in water and form neutral solutions

As the number of carbon atoms increases, the solubility of the alcohol in water decreases

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12
Q

describe how the alcohols react with sodium
e.g. ethanol + sodium

A

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

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13
Q

methanol + sodium
ethanol + sodium
propanol + sodium
butanol + sodium

A

methanol + sodium –> sodium methoxide + hydrogen
ethanol + sodium —> sodium ethoxide + hydrogen
propanol + sodium —-> sodium propoxide + hydrogen
butanol + sodium —-> sodium butoxide + hydrogen

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14
Q

describe how the alcohols react with an oxidising agent

e.g. ethanol reacting with an oxidising agent

A

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

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15
Q

methanol/ethanol/propanol/butanol reacting with an oxidising agent

A

oxidising agent
methanol —————> methanoic acid + water

              oxidising agent ethanol--------------->    ethanoic acid + water

              oxidising agent propanol--------------->    propanoic acid + water

              oxidising agent butanol--------------->    butanoic acid + water
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16
Q

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

A

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

17
Q

COMPLETE AND BALANCE THIS EQUATION
C4H9OH + O2 –> ________

A

C4H9OH + 6O2 —> 4CO2 + 5H2O

18
Q

describe the structures of the first four carboxylic acids

A

a compound that contains the -COOH functional group

19
Q

describe what happens when carboxylic acids dissolve in water

A

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+

20
Q

write out the equation of ethanoic acid dissociating in water - ethanoic acid in aqueous solution

describe what is happening

A

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

21
Q

describe the reaction of carboxylic acids with metal carbonates

ethanoic acid reacting with sodium carbonate

A

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)

22
Q

propanoic acid + potassium carbonate
complete the reaction
identify the salt

A

propanoic acid + potassium carbonate –> potassium propanoate + carbon dioxide + water

salt - potassium propanoate

23
Q

describe the reaction of carboxylic acids with an alcohol

A

When we react a carboxylic acid with an alcohol, we make a molecule called an ester. We also make water.

24
Q

Explain uses of esters

A

Esters are useful molecules are they often have a pleasant smell
They are used a lot in foods

25
Q

carboxylic acid functional group

A

–COOH

26
Q

first four carboxylic acids
draw their displayed formula
write out their structural formulas

A

https://bam.files.bbci.co.uk/bam/live/content/zq8y8mn/medium

c=o and c-oh can be at right angles

27
Q

write out reaction of ethanoic acid and ethanol

A

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

28
Q

conditions for reaction of ethanoic acid and ethanol

A

This reaction requires sulfuric acid as a catalyst

29
Q

ester functional group

A

-COO

30
Q

Name all the homologous series

A

Alkanes
Alkenes
Alcohols
Carboxylic Acids
Esters

GCSE Chemistry (43 decks)

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