Alcohols 3.3.5 Flashcards
When you have a compound that has an alcohol and a higher priority group, how do you name it
Hydroxy as the beggining prefix
There are primary, secondary and tertiary Alcohols, which ones are the most stable
Tertiary alcohol ad alkyl groups donate electrons to carbon atom which increases stability
Why do Alcohols have a greater boiling point than alkanes with a similar Mr
Alkenes only had VDW forces betweeb molecules
Alcohols have VDW forces and hydorgen bonding between molecules
Hydrogen binding is a stronger intermolecular force than VDW force therefore requires more energy to overcome
Why are Alcohols soluble in water
OH group can form Hydrogen bonds with water molecules
Explain the link between size of Alcohols and solubility and give the reasoning
As chain length of alcohol increases, solubility decreases as non polar VDW dominate
What are the uses of alcohol
Fuels
Solvents
Alcoholic drinks
What are the 2 ways of producing ethanol
Hydration of ethene
Fermentation
What are the conditions needed in the Hydration of ethene
Concentrated phosphoric acid
300°C
60 atmospheres
Excess steam
Ethanol SAMSUNG NOTES
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Give a brief summary of hoe ethanol is produced from fermentation
Carbohydrates in plants broken down to sugars
Then converted into ethanol by the action of enzymes from yeast
Give the symbol ewuation for ethanol production via fermentation
What are the conditions
C6H12O6 -> 2C2H5OH + 2CO2
Anaerobic
Yeast
37°
Why are anaerobic conditions used during fermentation
Oxygen from air is kept put to prevent oxidation of ethanol to ethanoic acid
Industrial fermentation is carried out at 37°C rather than 25°C, what is an advantage and disadvantage
ADVANTAGE Ethanol is produced at a faster rate
DISADVANTAGE more energy used
What is the issue with ethanol produced during fermentation and how is this dealt with
Ethanol is Impure as it is aqeuoues
Use Fractional distillation to sperate water and ethanol as they have different boiling points
Fermentation Samsung notes
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What is the mechanism when Alcohols are turned into alkenes
Elimination (dehydration)
Elimination Samsung notes
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What needs to be present for an alcohol to be oxidised and what is the specific one used here
Oxidising agent (acidification potassium dichromate)
Alcohols can be oxidised by oxidising agents into….
Carboxylic acids, aldehyde, ketone
When acidified potassium dichromate is reduced, explain the colour change when alcohol is oxidised
Orange to green
What can primary Alcohols be oxidised into
Aldehyde and carboxylic acid
What can secondary Alcohols be oxidised into
Ketone
When primary Alcohols are oxidised into Aldehyde, what are the required conditions
Acidified, heat, distillation
When primary Alcohols are oxidised to carboxylic acids, what are the required conditions
Acidified, heat under reflux and excess acidified potassium dichromate (VI) solution
When secondary Alcohols are oxidised into ketones, what are the required conditions
Acidified, heat under reflux
When an alcohol is being oxidised, what symbol do we use above the arrow
What about if it is in excess for example when primary Alcohols are oxidised into carboxylic acids
[O]
2[O]
What is refluxing and when is this used
The continuous boiling and condensing if a reaction mixture
This is used when you have volatile reactants
In distillation, why does water enter from the bottom of the condenser
What would happen if water entered from the top
To allow efficient cooling
If water entered from the top, the hot vapour would heat up the vapour so water would not be cool enough to allow efficient condensation
Why do tertiary Alcohols not get oxidised
They don’t react with potassium dichromate so it does not get oxidised by it
In terms of elements, in oxidation of Alcohols, what does the oxidising agent remove
It removes H from OH group and H from C attached to OH group
Why are antibumping granules added in distillation and reflux
To make boiling smoother by forming small, even bubbles
TOLLEN’S REAGENTS(SILVER MIRRPR TEST)
What ions does it contain? What is it reduced to? What colour is this?
What is this used to test for
Other contains colourless Ag+ ions which are reduced to Ag
Metallic silver colour (colourless solution forms a silver mirror)
Used to test for aldehydes that are being oxidised we ketones cannot be oxidised so no reaction
Whar are the two tests for differentiating between a ketone and aldehyde
Tollens’ reagents
Fehling’s solution
Explain the fehling’s solution test
Contains Copper(II) ions
It is a blue solution and when warmed in the presence of an aldehyde, a brick red precipitate of copper(I) oxide forms
How to test for carbon dioxide
Bubble the gas through liimwater and limewater turns cloudy if carbon dioxide is present
Last week SAMSUNG NOTES
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