Topic 17: Further organic chemistry

Question 1

chiral refers to

Answer 1

an atom in a molecule that allows it to exists as non-superimposable forms. it can also refer to the molecule itself

Question 2

asymmetric refers to

Answer 2

a carbon atom in a molecule that is joined to four different atoms or groups

Question 3

enantiomers are

Answer 3

isomers that are related as objects and mirror image

Question 4

a substance shows optical activity is

Answer 4

it rotates the plane of polarisation of plane-polarised light

Question 5

plane-polarised light is

Answer 5

monochromatic light that has oscillations in only one plane

Question 6

unpolarised light has

Answer 6

oscillations in all planes at right angles to the direction of travel

Question 7

a polarimeter is

Answer 7

the apparatus used to measure the angle of rotation caused by a substance

Question 8

a polariser is

Answer 8

a material that converts unpolarised light into plane-polarised light

Question 9

an analyser is

Answer 9

material that allows plane-polarised light to pass through it

Question 10

a racemic mixture is

Answer 10

an equimolar mixture of two enantiomers hat has no optical activity

Question 11

a mechanism described as bimolecular has

Answer 11

two species reacting in the rate-determining step, SN2

Question 12

a mechanism described as unimolecular has

Answer 12

one species reacting in teh rate-determining step, SN1

Question 13

nucleophilic addition is

Answer 13

a type of mechanism in which a molecule containing two atoms or groups is added across a polar double bond (usually C=O), and the attacking species in the first step is a nucleophile

Question 14

derivatives are

Answer 14

compounds formed from other compounds, especially when the properties of the derivatives can be used to identify the original compound

Question 15

hydrolysis is

Answer 15

the breaking of a compound by water into two compounds

Question 16

condensation polymerisation refers to

Answer 16

the formation of a polymer, usually by the reaction of two different monomers, and in which a small molecule is also formed

Question 17

the original meaning of aromatic was…

the new meaning is ….

Answer 17

was. .. a description of the smell of certain organic compounds
now. … a description of the bonding in a compound - delocalised electrons forming pi bonding in a hydrocarbon ring

Question 18

a halogen carrier is

Answer 18

a catalyst that helps to introduce a halogen atom into a benzene ring

Question 19

the basicity of a base is

Answer 19

the extent to which it can donate a lone pair of electrons to the hydrogen atom of a water molecule

Question 20

an addition-elimination reaction occurs when

Answer 20

two molecules join together, followed by the loss of a small molecule, usually H2O or HCl

Question 21

the isoelectric point of an amino acid is

Answer 21

the pH of an aqueous solution in which it is neutral

Question 22

a zwitterion is

Answer 22

a molecule containing positive and negative charges but which has no overall charge

Question 23

a peptide bond is

Answer 23

the bond formed by a condensation reaction between the carbonyl group (C=O) of one amino acid and the amino group (NH2) of another amino acid

peptide: CO -NH

Question 24

a hazard is

Answer 24

a property of a substance that could cause harm to a user

Question 25

a risk is

Answer 25

the possible effect that a substance may cause to a user, and this will depend on factors such as concentration and apparatus. the level of risk is controlled using control measures

Question 26

the stationary phase in paper chromatography is

Answer 26

the liquid or solid that does not move

Question 27

the mobile phase is

Answer 27

the liquid that moves through the stationary phase and transports the components

Question 28

high resolution mass spectrometry (HRMS) is

Answer 28

a type of mass spectrometry that can produce Mr values with several decimal places, usually four or more

Question 29

nuclear magnetic resonance spectroscopy (NMR spectroscopy) is

Answer 29

a technique used to find the structures of organic compounds. it depends on the ability of nuclei to resonate in a magnetic field

Question 30

the chemical shift of a proton (or group of protons) is

Answer 30

a number (in the units ppm) that indicates its behaviour to identify the chemical environment of the carbon atom or of the hydrogen atoms (protons) attached to it

Question 31

chemical environments of carbon atoms is a molecule are related to

Answer 31

whether the carbon atoms are identically, or differently, positioned within a molecule

Question 32

a peak in a 1H NMR spectrum shows

Answer 32

the presence of hydrogen atoms (protons) in a specific chemical environment

Question 33

an integration trace shows

Answer 33

the relative numbers of equivalent protons (i.e. in the same chemical environment)

Question 34

equivalent protons are

Answer 34

hydrogen atoms in the same chemical environment

Question 35

a splitting pattern is

Answer 35

the appearance of a peak as a small number of small sub-peaks very close to each other

Question 36

multiplets are

Answer 36

the different splitting patterns observed (singlets, doublets, triplets or quartets)