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Chemistry 2017 > Organic > Flashcards

Flashcards in Organic Deck (75):
1

What is the simplest hydrocarbon

Benzene , C6H6

2

What are aromatic hydrocarbons

Family of cyclic hydrocarbons

3

What functional group do alcohols contain

Hydroxyl group (OH)

4

What makes a primary alcohol

When the hydroxyl group is on the end, hence the carbon the OH is attached to is only attached to one other carbon for example 1-propanol CH3-CH2-CH2-OH

5

What do organic compounds with a hydroxyl functional group end in

-ol eg Pentanol

6

What constitutes a secondary alcohol

When the C the OH is bonded to is bonded to 2 other carbons,
Eg 2-Propanol

7

What constitutes a tertiary alcohol

When the C the OH is bonded to is attached to 3 other carbons
Eg, methyl 2-propanol

8

What is the condensed formula of aldehydes, plus two examples

R-CHO, methanal or ethanal

9

What is the condensed formula of ketones and what are two examples

R-CO-R'
Propanone and 2-pentanone

10

What is the condensed formula of carboxylic acids and what are two examples

-COOH OR - CO2H

Ethanoic acid and butanoic acid

11

What is the condensed formula of carboxylate ions and what is one example

R-COO(-)
Sodium ethanoate (CH3COONa)

12

What is the condensed formula of esters and what is one example

R-COO-R'
Methyl Ethanoate

13

What is the condensed formula of primary amines and what are two examples

R-NH2
1-butanamine
Methlyamine

14

For compounds with identical functional groups the boiling point '...' As the length of the chain increases

Increases

15

Why do boiling points increase As the length of carbon chains increase

As the strength of dispersion forces increase with molar mass, the longer the hydrocarbon chain the stronger the dispersion forces between molecules and higher the boiling point

16

What is the boiling point of alcohols in comparison to ketones and aldehydes

Alcohols have higher boiling points

17

Why is the boiling point of alcohols higher than that of ketones and aldehydes

As alcohol can form strong hydrogen bonds with each other due to the polar hydroxyl groups while aldehydes and ketones can only form weaker dipole dipole interactions

18

What is a carboxylic acid that has the same molecular formula as a group of esters called

Isomeric acid

19

Is the boiling point of esters of isometric acids lower

Esters

20

Why is the boiling point of esters much lower than their isometric acid

In the carboxyl groups in carboxylic acids hydrogen bonding can take place as they have C=O and O-H groups while only dipole dipole interactions can occur in esters

21

Why can't hydrocarbons soluble in water

They are non polar and like dissolves in like

22

What is required of polar functional groups form them to form hydrogen bonds with water

The carbon chain they are attached to must be less than 6 carbons long

23

What happens to the solubility of molecules if there is more than one polar functional group is present

It increases its solubility such as in the case of diols and diamines

24

Why are some molecules with polar functional groups classified as non Polar

As they have a long carbon chain of 6 carbon atoms or more

25

Are potassium and sodium carboxylates soluble in water? Why?

Yes, strong ion-dipole bonds form between the negatively charged carboxylate ions and polar water molecules

26

What's the general formula for carbohydrates

Cx(H2O)y

27

What are the simplest carbohydrates and what are two examples

Monosaccharides,
Glucose & Fructose

28

What is formed when two monosaccharides link together through the loss of a water and what is two examples

Disaccharides sucrose, maltose and lactose

29

What's formed when many monosaccharides join together and what's two examples

Polysaccharides Starch & Cellulose

30

Reaction for the hydrolysis of polysaccharides to monosaccharides

Starch (C6H10O5)n -H2O & enzyme-> nC6H12O6 Glucose

31

Reaction for the hydrolysis of disaccharides to monosaccharides

C12H22O11 -H2O & enzyme-> 2C6H12O6

32

Reaction for the fermentation of glucose to ethanol and carbon dioxide

C6H12O6 -> 2CH2CH2OH + 2CO2

33

What is the optimum temperature for fermentation and what happens if this the temperature is outside this range

20 & 30 degrees, enzymes will denature if it becomes too hot

34

What happens if oxygen enters the fermentation vessel

As fermentation is anaerobic process and if oxygen does enter it can bring about the oxidation of ethanol to ethanoic acid

35

In fermentation should the solution be acidic or alkaline

Acidic

36

What's a primary alcohol

An alcohol where the carbon atom the hydroxyl group is bonded to is directly bonded to only one other carbon atoms
Example: Methanol CH3-OH

37

What's a secondary alcohol

An alcohol where the carbon atom the hydroxyl group is bonded to is directly bonded to two other carbon atom
Eg: 2-Pentanol

38

What's a tertiary alcohols

An alcohol where the carbon atom the hydroxyl group is bonded to is directly bonded to three other carbon atom
Example: 2-methyl-2-butanol

39

Where do the differences arise in the three classes of alcohols

When they react with oxidising agents

40

What happens to primary alcohols when they're oxidised

They form the corresponding aldehyde, if there is continued contact with the oxidising agent the aldehyde is further oxidised to the corresponding carboxylic acid

41

What happens to secondary alcohols are oxidised

They form the corresponding ketones, does not undergo further oxidation

42

What happens when tertiary alcohols are oxidised

They are not readily oxidised! Do no react with an acidified dichromate solution

43

What colour change occurs when primary and secondary alcohols react with potassium dichromate

Orange -> Green however heating is required to observe the colour change at a reasonable time

44

What's the difference between aldehydes and ketones

Aldehydes the carboxyl group is in a terminal position
Ketones the carboxyl group is in a non-terminal position

45

How are aldehydes prepared

The controlled oxidation of primary alcohols

46

How are ketones prepared

By the oxidation of secondary alcohols, do not undergo further oxidation so the ketone does not need to be distilled off

47

Equation for the preparation of aldehydes

R-CH-OH --Cr2O7^2-/H+ & Heat--> R-CHO

48

What happens when aldehydes are heated with an acidified solution of dichromate ions and the relevant half equation

They undergo oxidation to carboxylic acids
RCHO->RCOOH

49

What is tollens test

Heating aldehydes with ammoniacal silver nitrate solution where they undergo oxidation, under certain conditions can form a silver mirror on the reaction vessel

50

How can carboxylic acid be prepared

By heating primary alcohols or aldehydes with excess acidified dichromate solution

51

What do carboxyl acid molecules contain

Carboxyl group -COOH
A carbonyl group and a hydroxyl group attached to the same atom

52

Ionisation of carboxylic acids in water equation

RCOOH + H2O ->

53

Neutralisation of carboxylic acid by hydroxide ions

RCOOH + OH^- -> RCOO^- + H2O

54

Neutralisation of carboxylic acids by carbonate ions

2RCOOH + CO3^2^- -> 2RCOO^- + H2O + CO2

55

Neutralisation of carboxylic acid by hydrocarbonate ions

RCOOH + HCO3^- -> RCOO^- + H2O + CO2

56

Are carboxylate salts soluble in water? Why/ why not?

They are soluble in water due to the strong ion-dipole bonds that forms between the negatively charged carboxylate ions and polar water molecules

57

Why are the structures of aspirin and ibuprofen insoluble, how is this overcome

They have a large non polar component, they are usually mixed with sodium hydrogencarbonate, when mixed with water the the carboxylic group react to form water soluble carboxylate ions

58

Why are drugs mixed with sodium hydrogencarbonate

The drug becomes easier to administer and faster acting

59

What's the difference in structure of esters and carboxylic acids k

The hydrogen atom of the carboxylic acid has been replaced by an alkyl group in the ester

60

How are esters prepared and what is this known as

Reacting, under reflux, an alcohol with a carboxylic acid in the presence of concentrated sulphuric acid as a catalyst
Esterification

61

What is reflux and what does this allow

Process by which a mixture of the reactants and products is boiled for a prescribed period of time, allows extended heating of the reaction mixture without loss of reactant and products by evaporation

62

Two ways to increase the yield of an ester

Use excess alcohol or excess carboxylic acid
Remove water as its formed

63

What is the hydrolysis of esters

Reverse of esterification where water is consumed as a reactant

64

Products of hydrolysis of esters in acidic conditions

Carboxylic acid and an alcohol, reaction is catalysed by the acid

65

Products of hydrolysis of esters in alkaline conditions

Carboxylate ions and an alcohol
As there are ions reaction is irreversible

66

How are amines classified

Into derivatives of ammonia depending on how many carbons the N is attached to i.e if 1 then is primary

67

What happens when amine molecules accept a proton

Form a positively charged ammonium ion known as the protonated form of the amine

68

Are protonated amines soluble in water why/ why not?

Yes, they form strong ion-dipole bonds between positively charged protonated amine ions and polar water molecules

69

How are drugs with tertiary amine groups usually administered

Water-soluble chloride salts

70

What's an amide

A molecule that has an amino group attached to a carboxyl group eg propenamide

71

Theoretically How could an amide be prepared

A condensation reaction between ammonia or amine with a carboxylic acid

72

What do Amino acids consist of

At least one amine functional group and one carboxyl functional group with a central carbon Atom,

73

What is a zwitterion

The result of amino acids undergoing self ionisation where a proton a transferred from the carboxyl group to the amine group in the same molecule

74

What is formed in nature when a carboxyl group from one amino acid undergoes a condensation reaction with an amine group from another amino acid

A dipeptide joined by a peptide link - forms water too

75

Result of the continuation of condensation process between two amino acids

Formation of a polypeptide (proteins)