Alcohols

Question 1

What is the general formula of alcohols?

Answer 1

CnH2n+2 O

Question 2

What 3 types of alcohols are there?

Answer 2

Primary
Secondary
Tertiary

Question 3

What is the most stable type of alcohol?

Answer 3

Tertiary

Made via a tertiary carbocation

Question 4

What 3 things affect the melting/boiling point of alcohols?

Answer 4

Number of H bonds each molecule can make
Number of e- (strength of LDF)
Surface area of contact

Question 5

Are alcohols soluble?

Answer 5

Yes, can form H bonds with water

Question 6

What affects the solubility of alcohols?

Answer 6

Number of H bonds the molecule can form (more H bonds=more soluble)
Length of non polar section

Question 7

What affects viscosity of alcohols?

Answer 7

Number of H bonds it can make (more H bonds, stronger IMF, More viscous)

Question 8

Why do alcohols burn more completely than alkanes?

Answer 8

They contain oxygen so less oxygen is needed to make it burn completely.

Question 9

What is the functional group isomer of alcohols?

Answer 9

Esters

Question 10

What have higher boiling points, alcohols or esters?

Answer 10

Alcohols as H bonds are stronger than esters

Question 11

What is used to oxidise alcohols?

Answer 11

Acidified potassium dichromate (VI)

H+/K2Cr2O7

Question 12

What do you observe when alcohols are oxidised?

Answer 12

Solution goes from orange to green

Question 13

Why does the solution go from orange to green when alcohols are oxidised?

Answer 13

Chromium is reduced so turns green and this is what proves that alcohols are oxidised

Question 14

What type of alcohols aren’t oxidised?

Answer 14

Tertiary

Question 15

What type of alcohols are oxidised the quickest?

Answer 15

Primary

Question 16

What is dehydration?

Answer 16

Removal of water

Question 17

What is used in dehydration of alcohols?

Answer 17

Concentrated H3PO4

Question 18

What 2 things are made in dehydration of alcohols?

Answer 18

Alkene and water

Question 19

What type of reaction is dehydration?

Answer 19

Elimination

Question 20

What is made when a primary alcohol is oxidised and heated and distilled?

Answer 20

Aldehyde and water

Question 21

What is made when a primary alcohol is oxidised and heated under reflux?

Answer 21

Carboxylic acid and water

Question 22

What is made when an aldehyde is oxidised and heated under reflux?

Answer 22

Carboxylic acid

Question 23

What is made when a secondary alcohol is oxidised and heated under reflux?

Answer 23

Ketone and water

Question 24

What is the definition of reflux?

Answer 24

Continuous evaporation and condensation of a volatile substance without the loss of any product to prevent the liquid boiling dry

Question 25

How many moles of oxidising agent do you need when turning a primary alcohol into a carboxylic acid?

Answer 25

2 as 2 oxidising reactions occur

Question 26

What is the distillate when oxidising and heating and distilling a primary alcohol?

Answer 26

The aldehyde produced by distillation

Question 27

Why is heating under reflux better than heating and distilling for secondary alcohols?

Answer 27

Ensures all reactants are turned into products

Question 28

Which do you use to work out the maximum amount of moles of products, excess or limiting?

Answer 28

Limiting

Question 29

How do you work out the limiting reactant?

Answer 29

Molar ratio reactants | Do moles divided by ratio, smallest number is limiting.

Question 30

Once you know limiting reactant how do you work out the maximum amount of moles of products?

Answer 30

Molar ratio limiting to product | Moles of limiting/ratio of limiting X ratio of product

Question 31

Definition/equation for percentage yield

Answer 31

(Amount of product / Theoretical amount of product) | X100

Question 32

What does percentage yield tell you?

Answer 32

How efficient a reaction is

Question 33

What is the problem with percentage yield?

Answer 33

Doesn't take into account for the waste products

Question 34

What is the definition for atom economy?

Answer 34

(RFM of desired products / Sum of RFM's of all products) | X100

Question 35

What is the atom economy in addition reactions?

Answer 35

100% all the time!

Question 36

How do you increase atom economy?

Answer 36

FInd other uses for waste products - no longer waste | Change an atom in waste to atom in same group with lower RFM

Question 37

What are some examples of waste products that could have other uses?

Answer 37

HCl - dissolved in water and bottled to make acid - sold to schools NaCl - make table salt CO2 - fizzy drinks, fire extinguishers

Question 38

Can water be used to stop it being waste?

Answer 38

No, too common so is always waste

Question 39

What equipment do you need for H.U.R?

Answer 39

``` Metal clamp stand Clamp Heat Round bottomed flask Condenser Water tap Anti-bumping granules Rubber tubing ```

Question 40

What equipment do you need for heat and distil?

Answer 40

``` Same as reflux AND Still head 3 clips 2 clamp stands (instead of 1) Thermometer Screw tap adapter Reciever ```

Question 41

How do you work out the aqueous layer in the separating funnel?

Answer 41

Add water, aqueous layer will get bigger

Question 42

How do you remove the acid impurities in the separating funnel?

Answer 42

Add a carbonate Will fizz if H+ is present Turn upside down and release gas Repeat until doesn't fizz

Question 43

What happens to the organic and aqueous layers in the separating funnel after acid impurities have been removed?

Answer 43

Run off 2 separate layers into separate beakers. | Keep organic layer

Question 44

After separating organic layer from aqueous layer what do you do?

Answer 44

Dry the liquid using an anhydrous salt

Question 45

What are the three anhydrous salts?

Answer 45

CaCl2 - hydrocarbons CaSO4 - General drying MgSO4 - General drying

Question 46

When do you stop adding anhydrous salt?

Answer 46

Until there are no lumps/until a fine powder

Question 47

After drying organic product what do you do?

Answer 47

Decant/filter off liquid | Redistil (specific temperature to remove other organic products)