Chapter 15 - Alcohols

Question 1

What is an alcohol

Answer 1

organic molecules with the hydroxyl functional group
CnH2n+1OH
add the suffix -ol

Question 2

why are alcohols solulable in water

Answer 2

because they are able to form hydrogen bonds with water molecules since the OH bond is very polar

Question 3

are longer or shorter alcohols more soluble in water and why

Answer 3

shorter alcohols, because a greater region of the molecule is polar

Question 4

what is the carbonyl functional group

Answer 4

any molecule that has a C=O bond has the carbonyl functional group
they are separated into ketones, aldehydes, and carboxylic acids

Question 5

what are the features of aldehydes

Answer 5

aldehydes are molecules with the C=O group on the last/first carbon of the chain
they dont need a position number and are shown by the suffix -anal
they form only from primary alcohols
RCHO where R is an alkyl group

Question 6

what are the features of ketones

Answer 6

they form from the oxidation of secondary alcohols
the C=O group is on any carbon in the carbon chain that isnt the first or last ones
they have the suffix -one and you need to indicate the position number unless is propanone
RCOR’ where R and R’ are alkyl groups

Question 7

what are features of carboxylic acids

Answer 7

they form from the oxidation of aldehydes
RCOOH where R is a methyl group
add the suffix -anoic acid, no position number needed

Question 8

how are alcohols formed

Answer 8

the hydration of alkenes
or fermentation using yeast

Question 9

what reagent is used to oxidise an alcohol

Answer 9

acidified potassium dichromate

Question 10

what colour change can we expect to see when acidified potassium dichromate is added to a primary alcohol

Answer 10

green to orange

Question 11

what colour change can we expect to see when acidified potassium dichromate is added to a secondary alcohol

Answer 11

green to orange

Question 12

what colour change can we expect to see when acidified potassium dichromate is added to a tertiary alcohol

Answer 12

no change (remains green)

Question 13

what reagent can be added to an alcohol to test whether it is primary or secondary

Answer 13

tollens reagent

Question 14

what colour change can we expect to see when tollens reagent is added to a primary alcohol

Answer 14

silver mirror forms

Question 15

what colour change can we expect to see when tollens reagent is added to a secondary alcohol

Answer 15

no change