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Flashcards in Organic Deck (66):
1

what is cracking?

Breaking long chain alkanes into smaller hydrocarbons

2

Thermal cracking

High temperature 1000°C
high-pressure 70 atm
Produces a lot of alkenes

3

Catalytic cracking

Zeolite catalyst
slight pressure
high temperature 450°C
mostly aromatic hydrocarbons and motor fuels produced

4

What do you get when you burn alkanes in plenty of oxygen?

Carbon dioxide and water

5

Products of incomplete combustion

Carbon monoxide or carbon particles (soot)

6

How is carbon monoxide poisonous?

It binds to the same sites on haemoglobin molecules in the red blood cells as oxygen molecules. So oxygen can’t be carried around the body

7

How is carbon monoxide removed from exhaust gases

Catalytic converters

8

What is the greenhouse effect

Greenhouse gases in our atmosphere absorb infrared heat and emit some of the energy back towards earth keeping it warm

9

How does nitrogen oxides pollute the air

Hydrocarbons and nitrogen oxides reacts in the presence of sunlight to form ground level ozone which makes up smog.

10

How does sulphur dioxide gas pollute the atmosphere

It dissolves in moisture and is converted into sulphuric acid which causes acid rain destroys trees and vegetation and corrodes buildings and statues and kills fish in lakes

11

How is sulphur dioxide removed from power stations fluegases

Powdered calcium carbonate or calcium oxide is mixed with water = alkaline slurry
acidic sulphur dioxide gas reacts with the calcium compounds to make harmless calcium sulphate

12

What are the conditions for free radical substitution

UV light

13

How does the Ozone protect us

Absorbs ultraviolet radiation from the Sun stopping it reaching us
Can cause sunburn or even skin cancer

14

What are the conditions for elimination

Warm dissolved in ethanol

15

Test for alkenes

Bromine water goes from Orange to colourless

16

What’s a polymer

Long chain molecules formed from monomers joined together

17

How do you make ethene from ethanol

Heat with a concentrated sulphuric acid catalyst
To produce ethene and water

18

Hydration of ethene by steam conditions

300°C
60 atm
Solid phosphoric (V) acid catalyst

19

Fermentation of glucose

Yeast in anaerobic conditions
produces ethanol and carbon dioxide
Optimum temperature 30 to 40°C

20

What is a biofuel

Fuel that’s made from biological material that’s recently died

21

Oxidising alcohols (Reagent and Method for primary alcohols)

Oxidise using potassium dichromate acidified with sulphuric acid
Distil to get aldehyde
reflux to get carboxylic acid

22

Oxidation of alcohols results

Primary alcohols oxidised to aldehydes and then to carboxylic acids
secondary alcohols oxidised ketones
Tertiary alcohols aren’t oxidised

23

Tests to distinguish between aldehydes and ketones

Fehlings solution
-aldehyde blue to brick red precipitate
-ketone NVC

Tollens reagent
-Aldehyde Silver mirror
-Ketone NVC

24

Test tube reaction for primary, secondary and tertiary alcohols

Warm with acidified potassium dichromate
Primary orange solution turns green
Secondary orange solution turns green
Tertiary NVC

25

How to do tollens reagent

Silver nitrate solution
dilute sodium hydroxide solution light brown precipitate
dilute ammonia solution until precipitate dissolve completely

26

Test for carboxylic acids

Sodium carbonate
solution begins to fizz if positive
bubble gas through limewater
if CO2 limewater turns cloudy

27

What are high resolution mass spectrometers

Measure atomic and molecular masses extremely accurately

28

What is infrared spectroscopy

Beam of IR radiation is passed through sample of a chemical
Absorbed by covalent bonds increasing their vibrational energy
bonds between different atoms absorb different frequencies of IR radiation

29

What is the fingerprint region

500 to 1500
Unique to particular compound

30

What is racemate

Contains equal quantities of each enantiomer of an optically active compound
no optical activity

31

Common reducing agent

NaBH4 dissolved in water with methanol

32

How to make esters

Heat a carboxylic acid with an alcohol in the presence of a strong acid catalyst. Usually hydrochloric acid

33

Uses of esters

Flavourings for food industry
Good solvents in glues and printing inks
Plasticises to make plastic more flexible

34

Acid Hydrolysis of esters Conditions

Reflux with dilute acid such as hydrochloric or sulphuric

35

Base hydrolysis of esters conditions

Reflux with alkali such as sodium hydroxide

36

How to convert vegetable oils into biodiesel

React with methanol using potassium hydroxide as a catalyst

37

Why is ethanoic anhydride used in industry to make aspirin

Cheaper than ethanoyl chloride
safer to use as less corrosive and doesn’t produce dangerous hydrogen chloride fumes

38

Common drying agent

Calcium chloride

39

How to get nitrobenzene

Warm benzene with concentrated nitric and sulphuric acid

40

How to make nitrobenzene. Including equations of electrophile generation

Warm benzene with concentrated nitric or sulphuric acid
Sulphuric acid axis catalyst to make nitronium ion NO2 + Which is the electrophile
HNO3 +H2SO4 -> H2NO3+ + HSO4-
H2NO3+ -> NO2+ +H2O

41

How do quaternary ammonium salts act as cationic surfactants?

The long hydrocarbon tail will bind to nonpolar substances such as grease whilst the cat ionic head will dissolve in water

42

Why are Quaternary ammonium salts used often in fabric conditioners?

The positively charged ammonium ion will bind to negatively charged surfaces such as hair and fibre getting rid of static

43

Why are a means with benzene rings the weakest bases?

The benzene ring draws electrons towards itself and the nitrogen lone pair get partially delocalised onto the ring so the electron density on the nitrogen decreases making the lone pair less available

44

Why are amines with alkyl groups stronger bases?

The alkyl groups push electrons on to attached groups so the electron density on the nitrogen atom increases making the lone pair more available

45

How do you make an amine from a halogenoalkane?

Heat with excess ammonia

46

What do you use to make a nitrile into a primary amine?

Use lithium aluminium hydride (LiAlH4) in a non-aqueous solvent (such as dry ether) followed by some die loot acid

47

How are primary amines made from nitriles in industry?

Nitriles are reduced using hydrogen gas with a metal catalyst such as platinum or nickel at high temperature and pressure (catalytic hydrogenation)

48

How do you turn nitrobenzene into an aromatic amine?

Heat nitrobenzene with tin metal and concentrated hydrochloric acid reflux to make a salt
add sodium hydroxide solution

49

What are Polyamides made up of?

Dicarboxylic acids and diamines
Form amine links

50

What make up polyesters?

Dicarboxylic acids and diols
Form Ester links

51

How do you reverse condensation polymerisation?

Hydrolysis

52

Why are condensation polymers generally stronger and more rigid than addition polymers?

They are made up of chains containing polar bonds so have permanent dipole dipole forces and hydrogen bonds as well as van der Waals

53

What makes Polyalkanes non biodegradable?

They are made up of nonpolar carbon chains which makes them unreactive and chemically inert

54

What is a zwitterion?

And ion that has both negative and positive charge in different parts of the molecule

55

Thin-layer chromatography method To separate amino acid’s

Draw pencil line near the bottom of chromatography plate and put concentrated spot of mixture of amino acids
Dip the bottom of the plate into solvent
Once the solvents nearly reached the top take the plate out and mark the solvent front with a pencil
Either spray ninhydrin solution on the plate to turn the spots purple or use special plate that has fluorescent dye so it glows when UV light shines on it
Work out Rf values

56

Why can amino acids be separated and identified using thin-layer chromatography?

They have different R groups so will all have different solubilities in the same solvent

57

How do you work out Rf values?

Distance travelled by spot/Distance travelled by solvent

58

What are proteins?

Condensation polymers of amino acids joined together by peptide links

59

What does the chiral centre of an enzyme called the active site to be?

Stereospecific so they only work on one enantiomer of the substrate

60

What is cisplatin?

A complex of platinum with two chloride ion ligands and two ammonia ligands in a square planar shape
its used as an anti cancer drug

61

How does cisplatin treat cancer?

Binds to the DNA causing kinks in the helix which stop proteins that replicate it from copying it properly stopping tumour cells reproducing

62

Describe in detail how cisplatin causes kinks in the DNA helix?

The nitrogen atom on a guanine base forms a coordinate bond with cisplatins platinum ion, replacing one of the chloride ions.(ligands substitution)
A second nitrogen atom from another guanine replaces the second chloride ion
The cisplatin bounded causes a kink so the DNA strands can’t unwind and be replicated

63

What is the standard substance in NMR spectroscopy And why is it used?

Tetramethylsilane
It has 12 hydrogen atoms all in identical environments so produces a single absorption keep well away from other absorption peaks
It is inert (so won’t react with the sample),non-toxic and volatile (so easy to remove)

64

What are the solvents for proton NMR

Deuterated solvents
CCl4

65

Thin layer chromatography method

Stationary phase is thin-layer of silica or alumina fixed to a glass or metal plate
Draw pencil line at bottom (baseline) And spots of mixtures
mobile phase Allow to dry and place in beaker
Leave till solvent near top and Mark solvent front
Leave to dry

66

Give two ways to reveal colourless chemicals in chromatography

Fluorescent dye on TLC plates when under UV light spots show as dark patches
Exposed to iodine vapour (locating agent) show up as brown/purple spots