What's in a Medicine?

Question 1

What is the general formula of carboxylic acids?

Answer 1

RCOOH

Where R is an alkyl group

Question 2

What is the formula of phenol?

Answer 2

C6H5OH

hydroxyl group attached to a benzene ring

Question 3

How can phenol be modified?

Answer 3

There can be various groups attached to the benzene ring. As long as there’s an -OH directly connected to the benzene, it is still a phenol.

Question 4

What is the general formula of acid anhydrides?

Answer 4

(RCO)2O

Question 5

What is the general formula of esters?

Answer 5

RCOOR’

Where the two R groups can be the same or can be different

Question 6

General formula of aldehydes?

Answer 6

RCHO

Question 7

General formula of ketones?

Answer 7

RCOR’

Where the two R groups can be the same or can be different

Question 8

General formula of ethers?

Answer 8

R-O-R’

Where the two R groups can be the same or can be different

Question 9

Define what a primary alcohol is.

Answer 9

An alcohol where the -OH is bonded to a carbon that is bonded to one other carbon

Question 10

Give the general formula of primary alcohols

Answer 10

RCH2OH

Question 11

Define what a secondary alcohol is.

Answer 11

An alcohol where the -OH is bonded to a carbon that is bonded to two other carbons

Question 12

Give the general formula of secondary alcohols.

Answer 12

RCH(OH)R

Question 13

Define what a tertiary alcohol is.

Answer 13

An alcohol where the -OH is bonded to a carbon that is bonded to three other carbons

Question 14

Give the general formula of tertiary alcohols.

Answer 14

R2C(OH)R

Question 15

What can primary alcohols be oxidised to?

Answer 15

Aldhydes or carboxylic acids

Question 16

State the conditions and reagents needed for primary alcohols to be oxidised to aldehydes

Answer 16

A strong oxidising agent, such as acidified potassium dichromate(VI) solution, excess alcohol, and distillation

Question 17

State the conditions and reagents needed for primary alcohols to be oxidised to carboxylic acids

Answer 17

Excess oxidising agent and done under reflux

Question 18

What are secondary alcohols oxidised to?

Answer 18

Ketones

Question 19

State the conditions and reagents needed for secondary alcohols to be oxidised to ketones

Answer 19

Oxidising agent, such as acidified potassium dichromate(VI) solution and done under reflux

Question 20

Explain why tertiary alcohols can’t be oxidised

Answer 20

Oxidation of the -OH won’t happen unless there is a hydrogen attached to the carbon bonded to the -OH.

Question 21

What is the colour change when the dichromate(VI) ions are reduced to chromate(III) ions, when used as an oxidising agent?

Answer 21

Orange to green

Question 22

Explain what happens when neutral iron(III) chloride is added to a phenol

Answer 22

You get a purple solution because the phenol forms a complex ion with iron

Question 23

Why can phenols react with hydroxides to form salt and water, but not react with carbonates to form salt, CO2, and water?

Answer 23

Hydroxides are strong enough bases to remove a H+ from the phenol, but carbonates aren’t

Question 24

What do you have to react phenols with to get an ester?

Answer 24

Acid anhydrides

Carboxylic acids are also formed

Question 25

Name the two possible things alcohols react with to form esters

Answer 25

Carboxylic acids or acid anhydrides

Question 26

General reaction of alcohols with carboxylic acids

Answer 26

RCOOH + ROH --> RCOOR + H2O

Question 27

General reaction of alcohols with acid anhydrides

Answer 27

(RCO)2O + ROH --> RCOOR + RCOOH

Question 28

What are alcohols dehydrated to?

Answer 28

Alkenes

Question 29

What is another name for a dehydration reaction?

Answer 29

An elimination reaction because a small group of atoms break away from a larger molecule and aren't replaced.

Question 30

What are the two ways of dehydrating alcohols?

Answer 30

- Pass the alcohol vapour over hot aluminium oxide, the catalyst. - Reflux the alcohol with excess concentrated sulfuric acid at 170°C

Question 31

Why do chemists use recrystallisation?

Answer 31

It's a way to purify solid crude organic products from both insoluble and soluble impurities.

Question 32

Recrystallisation method:

Answer 32

1) Select a solvent in which the desired product is soluble at high temperatures, and insoluble at lower temperatures. 2) Dissolve in the minimum amount of hot solvent 3) Filter to remove insoluble impurities. Preheat the filter funnel & conical flask to stop the product crystallising at this stage. 4) Let the filtrate cool until crystals form. Collect the crystals by vacuum filtration. 5) Dry the crystals in an oven