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Chemistry (2017) > Key Terms > Flashcards

Key Terms Flashcards

1
Q

Accurate result

A

A result that’s really close to the true answer

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2
Q

Achiral molecule

A

A molecule that can be superimposed on its mirror image

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3
Q

Acid anhydride

A

A molecule formed from 2 identical carboxylic acid molecules, joined via an oxygen atom with the carbonyl groups on either side

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4
Q

Acid dissociation constant (Ka)

A

An equilibrium constant specific to weak acids that relates the acid concentration to the concentration of [H+] ions

Ka = [H+][A-] / [HA]

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5
Q

Acidic buffer

A

A buffer with a pH of less than 7 containing a mixture of a weak acid with one of its salts

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6
Q

Acyl chloride

A

A molecule which contains the functional group COCl

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7
Q

Acylation

A

When an acyl group (-COR) is added to a molecule

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8
Q

Addition polymer

A

A type of poly,we firmed by joining small alkenes (monomers) together

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9
Q

Adsorption

A

The attraction between a substance and the surface of the solid stationary phase in thin-layer chromatography, column chromatography and gas chromatography

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10
Q

Aim

A

The question an experiment is trying to answer

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11
Q

Alcohol

A

A substance with the general formula CnH(2n+1)OH

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12
Q

Aldehyde

A

A substance with the general formula CnH2nO which has a hydrogen and one alkyl group attached to a carbonyl carbon atom

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13
Q

Amide

A

A carboxylic acid derivative which contains the functional group CONH2

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14
Q

Amide link

A

The -CONH- group which is found between monomers in a polyamide

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15
Q

Amine

A

A molecule where one or more of the hydrogen atoms in ammonia have been replaced with an organic functional group, such as an alkyl or an aromatic group

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16
Q

Amino acid

A

A molecule with an amino group (NH2) and a carboxyl group (COOH)

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17
Q

Amphoteric

A

Having both acidic and basic properties

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18
Q

Anomalous result

A

A result that doesn’t fit in with the pattern of the other results in a set of data

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19
Q

Aromatic compounds

A

A compound that contains a benzene ring

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20
Q

Arrhenius equation

A

An equation that links the rate constant, k, to temperature and activation energy

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21
Q

Arrhenius plot

A

A graph where 1/temperature is plotted against ln k, where k is the rate constant

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22
Q

Autocatalysis

A

When a reaction is catalyses by one of its products

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23
Q

Base (of DNA)

A 
One of 4 molecule:
Adenine
Thymine 
Cytosine 
Guanine 
They're attached to the sugar-phosphate backbone in DNA
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24
Q

Basic Buffer

A

A buffer with a pH of more than 7 containing a mixture of a weak base with one of its salts

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25
Q

Bidentate ligand

A

A ligand that can form 2 co-ordinate bonds in a complex ion

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26
Q

Biodegradable

A

Will break down naturally

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27
Q

Biodiesel

A

A mixture of methyl esters of fatty acids which can be used as a carbon neutral fuel

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28
Q

Bond dissociation enthalpy

A

The enthalpy change when all the bonds of the same type in 1 mole of gaseous molecules are broken down

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29
Q

Born-Haber cycle

A

An enthalpy change that allows you to calculate the lattice enthalpy change of formation for a system

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30
Q

Brønsted - Lowry acid

A

A proton donor

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31
Q

Brønsted - Lowry base

A

A proton acceptor

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32
Q

Buffer

A

A solution that resists changes in pH when small amounts of acid or alkali are added

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33
Q

Catalyst

A

A substance that increases the rate of a reaction by providing an alternative reaction pathway with a lower activation energy. The catalyst is chemically unchanged at the end of the reaction.

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34
Q

Catalyst poisoning

A

When impurities in a reaction mixture bind to a catalyst’s surface, blocking reactants from being absorbed and reducing the effectiveness of the catalyst

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35
Q

Catalytic Hydrogenation

A

A chemical reaction in which hydrogen is added to an unsaturated molecule by reacting the molecule with molecular hydrogen (H2) in the presence of a catalyst.

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36
Q

Categoric data

A

Data that can be sorted into categories

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37
Q

Cationic surfactant

A

A surfactant which is positively charged.

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38
Q

Casual link

A

The relationship between 2 variables where a change in one variable causes a change in the other

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39
Q

Cell potential (Ecell)

A

The voltage between 2 half-cells in an electrochemical cell

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40
Q

Chelate effect

A

When monodentate ligands are substituted with multidentate ligands, the number of particles and the entropy of the system increases without enthalpy changing significantly. Reactions that result in an increase in entropy are most likely to occur, so multidentate ligands form much more stable complexes than monodentate ligands

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41
Q

Chemical shift

A

Nuclei in different environments absorb energy of different frequencies. NMR spectroscopy measures these differences relative to a standard substance - the difference is called the chemical shift (δ)

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42
Q

Chiral carbon

A

A carbon atom that has 4 different groups attached to it

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43
Q

Chromatogram

A

A visual record (such as a pattern of spots or a graph) of the results of a chromatography experiment

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44
Q

Chromatography

A

An analytic technique which uses a mobile phase and a stationary phase to separate out mixtures into their constituent components

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45
Q

Cisplatin

A

A platinum-containing complex ion with a square planar shape that can be used as an anti-cancer drug

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46
Q

Cis-trans isomerism

A

A special type of E/Z isomerism where 2 of the groups attached to the carbon atoms around the C=C double bond are the same

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47
Q

Clock reaction

A

A reaction where, after a period of time, there’s a sudden increase in the concentration of a product

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48
Q

Colorimeter

A

An instrument for measuring how much light is absorbed by a sample

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49
Q

Column chromatography

A

A type of chromatography where the stationary phase is a column packed with a solid, and the mobile phase is a liquid solvent

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50
Q

Complex ion

A

A metal ion surrounded by co-ordinatley bonded ligands

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51
Q

Condensation polymer

A

A type of polymer formed through a series of condensation reactions

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52
Q

Condensation reaction

A

A chemical reaction in which 2 molecules are joined together and a small molecule is eliminated

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53
Q

Contact Process

A

An industrially used method of producing sulfuric acid

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54
Q

Continuous data

A

Data that can have any value on a scale

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55
Q

Continuous monitoring

A

A method of following a reaction by monitoring the formations of a product or the loss of a reactant, over the course of a reaction

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56
Q

Control variable

A

A variable that is kept constant in an experiment

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57
Q

Co-ordinate bond

A

A covalent bond in which both electrons in the shared pair come from the same atom (also called a dative covalent bond)

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58
Q

Co-ordinate number

A

The number of co-ordinate bonds that are formed with the central metal ion in a complex ion

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59
Q

Correlation

A

The relationship between 2 variables

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60
Q

Corrosive substance

A

A substance that may cause chemical burns

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61
Q

d-block

A

The block of elements in the middle of the periodic table

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62
Q

d sub-level

A

A type of sub-level. Each can hold 10 electrons

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63
Q

Data Logger

A

A device that can record data readings automatically at set intervals and store them to be looked at later

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64
Q

Dative Covalent bond

A

A covalent bond in which both electrons in the shared pair come from the same atom (also called a co-ordinate bond)

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65
Q

Dependent variable

A

The variable that you measure in an experiment

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66
Q

Deuterated solvent

A

A solvent which has had all of its hydrogen atoms exchanged for deuterium atoms

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67
Q

Deuterium

A

An isotope of hydrogen. It contains one neutron, one proton and one electron

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68
Q

Diprotic acid

A

An acid that releases 2 H+ ions per molecule

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69
Q

Discrete data

A

Data that can only take certain values

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70
Q

Distillation

A

A method of separating liquids with different boiling points by generally heating them

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71
Q

Disulfide bond

A

A covalent bond between sulfur atoms in 2 different thiol groups

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72
Q

DNA

A

Deoxyribonucleic acid - 2 complementary polynucleotide chains joined together in a double helix structure

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73
Q

Double helix

A

A shape formed by 2 helices twisted around each other

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74
Q

Drying agent

A

An anhydrous salt, such as magnesium sulfate or calcium chloride, that can be used to remove water from an organic product

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75
Q

E/Z isomerism

A

A type of stereoisomerism that is caused by the restricted rotation about a C=C double bond. Each of the carbon atoms must have 2 different groups attached

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76
Q

Electric heater

A

A piece of equipment used to heat a reaction mixture, consisting of a plate of metal that is heated to a set temperature

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77
Q

Electrochemical cell

A

An electrical circuit made from 2 metal electrodes dipped in salt solutions and connected by a wire

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78
Q

Electrochemical series

A

A list of electrode potentials written in order from most negative to most positive

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79
Q

Electrode potential

A

The voltage measured when a half-cell is connected to a standard hydrogen electrode

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80
Q

Electromotive force (EMF)

A

Another name for cell potential

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81
Q

Electrophile

A

An electron deficient (and usually positively charge)species which is attracted to regions of high electron density

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82
Q

Electrophilic substitution

A

A reactions mechanism where an electrophile substitutes for an atom (or group of atoms) in a molecule

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83
Q

Enantiomer

A

A molecule that has the same structural formula as another molecule but with 4 groups arranged around a chiral carbon atom so that it is a non-superimposable mirror image of the other molecule

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84
Q

End point

A

The point in a titration at which all the acid is just neutralized and the pH curve becomes vertical

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85
Q

Endothermic reactions

A

A reaction that absorbs energy (ΔH is positive)

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86
Q

Energy gap (ΔE)

A

The amount of energy needed for an electron to transfer to a higher orbital

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87
Q

Enthalpy change of atomistion of a compound (ΔHat)

A

The enthalpy change when 1 mole of a compound in its standard states is converted to gaseous atoms

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88
Q

Enthalpy change of atomisation of an element (ΔHat)

A

The enthalpy change when 1 mole of gaseous atoms is formed from an element in its standard states

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89
Q

Enthalpy change of formation (ΔH f)

A

The enthalpy change when 1 mole of a compound is formed from its elements in their standard states under standard conditions

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90
Q

Enthalpy change of hydration (ΔHhyd)

A

The enthalpy change when 1 mole of aqueous ions is formed from gaseous ions

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91
Q

Enthalpy change of solution (ΔH sol)

A

The enthalpy change when 1 mole of an ionic substance dissolves in enough solvent to form an infinitely dilute solution

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92
Q

Entropy (S)

A

A measure of the amount of disorder in a system (e.g. the number of ways the particles can be arranged and the number of ways that the energy can be shared out between the particles)

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93
Q

Enzyme

A

A protein that acts as a biological catalyst

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94
Q

Equilibrium constant

Kp

A

A ratio worked out from the partial pressures of the gaseous products and reactants once a reversible reaction has reached equilibrium

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95
Q

Ester

A

A molecule that contains the functional group RCOOR

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96
Q

Ester link

A

The -COO- group which is found between monomers in a polyester

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97
Q

Esterification

A

Forming an ester by heating a carboxylic acid and an alcohol in the presence of a strong acid catalyst

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98
Q

Exothermic reaction

A

A reaction that gives out energy (ΔH is negative)

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99
Q

Fatty acid

A

A long chain carboxylic acid which can combine with glycerol to form a fat or an oil

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100
Q

Feasible reaction

A

A reaction that, once started, will carry on to completion, without any energy being supplied to it

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101
Q

Fehling’s solution

A

A blue solution of complexed coppe(II) ions dissolved in sodium hydroxide which can be used to distinguish between aldehydes and ketones

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102
Q

Filtration

A

A technique used to separate solids from liquids

103
Q

First electron affinity

A

The enthalpy change when 1 mole of gaseous 1- ions is made from 1 mole of gaseous atoms

104
Q

First ionisation energy

A

The enthalpy change when 1 mole of gaseous 1+ ions is formed from 1 mole of gaseous atoms

105
Q

Flammable substance

A

A substance that catches fire easily

106
Q

Free-energy change

A

A measure which links enthalpy and entropy changes to predict whether a reaction is feasible

107
Q

Fehling’s solution

A

A blue solution of complexed coppe(II) ions dissolved in sodium hydroxide which can be used to distinguish between aldehydes and ketones

108
Q

Filtration

A

A technique used to separate solids from liquids

109
Q

First electron affinity

A

The enthalpy change when 1 mole of gaseous 1- ions is made from 1 mole of gaseous atoms

110
Q

First ionisation energy

A

The enthalpy change when 1 mole of gaseous 1+ ions is formed from 1 mole of gaseous atoms

111
Q

Flammable substance

A

A substance that catches fire easily

112
Q

Free-energy change

A

A measure which links enthalpy and entropy changes to predict whether a reaction is feasible

113
Q

Fehling’s solution

A

A blue solution of complexed coppe(II) ions dissolved in sodium hydroxide which can be used to distinguish between aldehydes and ketones

114
Q

Filtration

A

A technique used to separate solids from liquids

115
Q

First electron affinity

A

The enthalpy change when 1 mole of gaseous 1- ions is made from 1 mole of gaseous atoms

116
Q

First ionisation energy

A

The enthalpy change when 1 mole of gaseous 1+ ions is formed from 1 mole of gaseous atoms

117
Q

Flammable substance

A

A substance that catches fire easily

118
Q

Free-energy change

A

A measure which links enthalpy and entropy changes to predict whether a reaction is feasible

ΔG = ΔH - TΔS

119
Q

Fuel cell

A

A device that converts the energy of a fuel into electricity through an oxidation reaction

120
Q

Gas chromatography (GC)

A

A type of chromatography where the stationary phase is a tube packed with a solid, and the mobile phase is an unreactive gas

121
Q

Haber process

A

An industrially used method of producing ammonia

122
Q

Haem

A

A part of the haemoglobin molecule, consisting of a central Fe(II) ion bonded to 4 nitrogen atoms from a porphyrin ring

123
Q

Haemoglobin

A

A protein found in blood that helps to transport oxygen around the body

124
Q

Half-cell

A

One half of an electrochemical cell

125
Q

Half-equation

A

An ionic equation that shows oxidation or reduction - one half of a full redox equation

126
Q

Halogen carrier

A

A molecule which can accept a halogen atom (eg AlCl3)

Used as a catalyst in Friedel-Crafts acylation reactions

127
Q

Hess’s law

A

The total enthalpy change of a reaction is always the same, no matter of the route taken

128
Q

Heterogeneous catalyst

A

A catalyst which is in a different physics state to the reactants

129
Q

Homogeneous catalyst

A

A catalyst which is in the same physical state as the reactants

130
Q

Hydrogen bonding

A

A type of weak bonding which occurs between hydrogen atoms and electronegative atoms in polar groups (eg -NH2 and -OH)

131
Q

Hydrolysis

A

A reaction where molecules are split apart by water molecules

132
Q

Hydroxynitrile

A

A molecule which contains a hydroxyl group (OH) and a nitrile group (CN)

133
Q

Hypothesis

A

A suggested explanation for a fact or observation

134
Q

Independent variable

A

The variable that you change in an experiment

135
Q

Indicatior

A

A substance that changes colour over a particular pH range

136
Q

Inhibitor

A

A molecule that is a similar shale to a substrate of an enzyme, that blocks the active site of the enzyme and stops it interacting with the substrate

137
Q

Initial rates method

A

An experimental technique that can be used to work out the orders of a reaction

138
Q

Integration trace

A

A line on a H1 NMR spectrum that has a change in height that is proportional to the area of the peak its next to

139
Q

Ionic product of water

Kw

A

A constant generated by multiplying the Kc for the dissociation of water by [H2O]
Kw = [H+] [OH-]

140
Q

Irritant substance

A

A substance that may cause inflammation or discomfort

141
Q

Isoelectric point

A

The pH at which the average overall charge on a molecule is zero

142
Q

Ketone

A

A substance with the general formula CnH2nO which has 2 alkyl groups attached to a carbonyl carbon atom

143
Q

Lattice dissociation enthalpy

A

The enthalpy change when 1 mole of a solid ionic compound is completely dissociated into its gaseous ions

144
Q

Lattice formation enthalpy

A

The enthalpy change when 1 mole of a solid ionic compound is formed from its gaseous ions

145
Q

Le Chatelier’s Principle

A

If there’s a change in concentration pressure or temperature, an equilibrium will move to help counteract the change

146
Q

Ligand

A

An atom, ion or molecule that donates a pair of electrons to a central metal ion in a complex ion

147
Q

Ligand substitution/ exchange reaction

A

A reaction where one or more ligands are changed for one or more other ligands in a metal complex ion

148
Q

Melting point apparatus

A

Equipment that can be used to test the purity of an organic product by measuring it’s melting point

149
Q

Metal-aqua complex ion

A

A species formed when metal ions dissolved in water. The water molecules from co-ordinate bonds with the metal ions

150
Q

Method

A

A set of instructions detailing how to carry out an experiment safety

151
Q

Methyl orange

A

A pH indicator that changes colour between pH 3.1 and 4.4

152
Q

Mobile phase

A

A liquid or a gas used in chromatography which contains molecules that can move

153
Q

Mole fraction

A

A measure of the proportion of a mixture that is made up of a particular substance

154
Q

Monodentate ligand

A

A ligand that can only form one co-ordinate bond in a complex ion

155
Q

Monomer

A

A small molecule which can join together with other monomers to form a polymer

156
Q

Monoprotic acid

A

An acid that releases one H+ ion per molecule

157
Q

Multidentate ligand

A

A ligand that can form 2 or more co-ordinate bonds in a complex ion

158
Q

Multiplet

A

A split peak on a H1 NMR Spectrum

Doublet, triplet, quartet

159
Q

n+1 rule

A

Peaks on a H1 NMR spectrum always split into the number of hydrogens on the neighbouring carbon(s), plus one

160
Q

N-substituted Amide

A

An Amide where one if the hydrogens attached to the nitrogen has been substituted with an alkyl group

161
Q

Nitration

A

A reaction in which a nitro group (NO2) is added to a molecule

162
Q

Nuclear magnetic resonance (NMR) spectroscopy

A

An analytic technique used to determine the relative environment of the nuclei in a compound

163
Q

Nucleophile

A

A species that forms a bond with an electrophile by donating a pair of electrons

164
Q

Nucleophilic addition-elimination

A

A reaction mechanism where a nucleophiles adds on to the δ+ carbon atom of a carbonyl group and another molecule is eliminated

165
Q

Nucleophilic substitution

A

A reaction mechanism where a nucleophiles substitutes for an atom (or group of atoms) in a molecule

166
Q

Nucleotide

A

A molecule that is made up of a phosphate ion, a pentose sugar, and a (genetic) base

167
Q

Optical isomer

A

A molecule that has the same structural formula as another molecule but with 4 groups arranged around a chiral carbon atom so that it is a non-superimposable mirror image of the other molecule

168
Q

Orbital

A

A region of a sub-level that contains a maximum of 2 electron

169
Q

Order of reaction (reaction order)

A

A number that tells you how the concentration of a particular reactant affects the reaction rate

170
Q

Ordered (ordinal) data

A

Categoric data where the categories can be put in order

171
Q

Oxidation

A

The loss of electrons

172
Q

Oxidation state

A

The total number of electrons an element has donated or accepted, also called the oxidation number

173
Q

Oxidising agent

A

Something that accepts electrons and gets reduced

174
Q

Oxidising substance

A

A substance that reacts to form oxygen, meaning that other substances burn more easily in its presence

175
Q

Partial pressure

A

The pressure that an individual gas, in a mixture of gases, exerts on a system

176
Q

Pentose sugar

A

A sugar with 5 carbon atoms

177
Q

Peptide

A

A polymer formed from reactions between amino acids

178
Q

Peptide link (bond)

A

The bonds which hold amino acids together in a protein

179
Q

pH

A

A measure of the hydrogen ion concentration in a solution

pH= -log[H+]

180
Q

pH chart

A

A chart that shows the colour of an indication at different pHs

181
Q

pH curve

A

A graph of pH against volume of acid/alkali added

182
Q

pH meter

A

An electronic device used to measure pH, made up of a probe connected to a digital display

183
Q

Phenolphthalein

A

A pH indicator that changes colour between 8.3 and 10

184
Q

Plane polarised light

A

Light in which all the waves are vibrating in the same plane

185
Q

Polyamide

A

A polymer containing Amide links between monomers. Can be formed from reactions between dicarboxylic acids and diamines

186
Q

Polyester

A

A polymer containing ester links between the monomers. Can be formed from reactions between dicarboxylic acids and diols

187
Q

Polymer

A

A long molecule formed from lots of repeating units (called monomers)

188
Q

Polynucleotide

A

A polymer formed of nucleotides

189
Q

Polypeptide

A

A polymer formed from reactions between amino acids

190
Q

Porphyrin

A

A multidentate ligand found in a number of biological molecules including haemoglobin

191
Q

Precise result

A

Results where the data have a very small spread around the mean

192
Q

Prediction

A

A specific testable statement about what will happen in an experiment, based on observation, experience or a hypothesis

193
Q

Primary structure (of proteins)

A

The first ‘level’ that describes the structure of protein - ie the sequence of amino acids in the polypeptide chain

194
Q

Protein

A

One or more polypeptides folded into a structure which has a biological function

195
Q

Purely ionic model of a lattice

A

A model which assumes that all the ions in a lattice are spherical and have their charge evenly distributed around them. This model is also known as the perfect ionic model

196
Q

Racemate (or racemic mixture)

A

A mixture that contains equal quantities of each enantiomer of an optically active compound

197
Q

Random error

A

An error introduced by a factor that you cannot control

198
Q

Rate constant

K

A

A constant in the rate equation for a reaction at a certain temperature. The larger it is the faster the rate of reaction.

199
Q

Rate-determining step

A

The slowest step in a reaction mechanism which determines the overall rate of a reaction

200
Q

Rate equation

A

An equation of the form rate = k[A]^m [B]^n which tells you how the rate of a reaction is affected by the concentration of reactants

201
Q

Reaction rate

A

The change in the amount of reactants or products over time

202
Q

Recrystallisation

A

A process of purifying a solid organic compound

203
Q

Redistillation

A

A process of purification, by repeatedly distilling

204
Q

Redox potential

A

A measure of how easily an atom, molecule or ion is reduced

205
Q

Redox reaction

A

A reaction where reduction and oxidation happens simultaneously

206
Q

Redox titration

A

A titration which can be performed

207
Q

Reducing agent

A

Something that donates electrons and gets oxidised

208
Q

Reduction

A

The gain of electrons

209
Q

Refluxing

A

A method of heating a reaction so that you can increase the temperature of an organic reaction to boiling without losing volatile solvents, reactants or products. Any vaporised compounds are cooled, condense and drip back into the reaction mixture

210
Q

Repeatable result

A

A result is repeatable if you can repeat an experiment multiple times and get the same result

211
Q

Repeating unit

A

A part of a polymer that repeats over and over again

212
Q

Reproducible result

A

A result is reproducible if someone else can recreate your experiment and get the same result you do

213
Q

Retention

A

The process of being absorbed onto the stationary phase in chromatography

214
Q

Retention time

A

The time taken for a component of a mixture to pass through a chromatography column to the detector at the other end

215
Q

Rf value

A

The ratio of the distance travelled by a spot to the distance travelled by the solvent in thin layer chromatography

216
Q

Risk assessment

A

A procedure carried out to identify any hazards associated with an experiment and how to reduce the risks these hazards present

217
Q

Salt bridge

A

A connection between 2 half-cells that ions can flow through, used to complete the circuit. Usually a piece of filter paper soaked in a salt solution or glass tube filled with a salt solution

218
Q

Sand bath

A

A piece of equipment used to heat a reaction mixture, consisting of a container filled with sand that can be heated to a set temperature

219
Q

Saturated fatty acid

A

A fatty acid that contains no double bonds - found in fats

220
Q

Second electron affinity

A

The enthalpy change when 1 mole of gaseous 2- ions is made from 1 mole of gaseous 1- ions

221
Q

Second ionisation energy

A

The enthalpy change when 1 mole of gaseous 2+ ions is formed from 1 mole of gaseous 1+ ions

222
Q

Secondary structure of proteins

A

The second ‘level’ that describes the structure of protein

(Eg how the primary structure folds and twists to form a a-helix or b-pleated sheet, held together by hydrogen bonds

223
Q

Separation

A

A technique to separate the water-soluble impurities out of an organic mixture. The aqueous and organic solutions can be separated as they are immiscible, and separate out into 2 distinct layers due to their different densities

224
Q

Solvent extractions

A

A form of separation, where the product is shaken vigorously with an immiscible solvent

225
Q

Solvent front

A

The distance travelled by the solvent in thin-layer chromatography

226
Q

Spectroscopy

A

The study of what happens when radiation interacts with matter

227
Q

Splitting patterns

A

Peaks in 1H NMR spectra may be split into further peaks. The resultant group of peaks is called a splitting pattern

228
Q

Standard conditions

A

298K (25°C)
100 kPa
All ion concentrations of 1.00 Moldm-3

229
Q

Standard electrode potential

A

The voltage measured under standard conditions when a half-cell is connected to a standard hydrogen electrode

230
Q

Standard hydrogen electrode

A

An electrode where hydrogen gas is bubbled through a solution of aqueous H+ ions under standard conditions

231
Q

Stationary phase

A

A solid, or a liquid held in a solid, used in chromatography which contains molecules that can’t move

232
Q

Stereoisomer

A

A molecule that has the same structural formula as another molecule but with the atoms arranged differently in space

233
Q

Stereoisomer

A

A molecule that has the same structural formula as another molecule but with the atoms arranged differently in space

234
Q

Stereospecific active site

A

An active site that only reacts with one enantiomer of a chiral compound

235
Q

Strong acid/base

A

An acid or base that fully dissociates in water

236
Q

Sub-level

A

A subdivision of an energy level

S,p.d.f

237
Q

Substrate

A

A molecule that is acted on by an enzyme

238
Q

Surfactant

A

A compound which is partly soluble and partly insoluble in water

239
Q

Synthetic route

A

A method detailing how to create a chemical

240
Q

Systematic error

A

An error introduced by the apparatus or method you use in an experiment

241
Q

Tertiary structure of proteins

A

The 3rd level that describes the structure of protein

ie how the secondary structure folds and twists to form a 3D molecule, held together by hydrogen and disulphide bonds

242
Q

Thin layer chromatography

A

A type of chromatography where the stationary phase is a plate coated with a solid and the mobile phase is a liquid solvent

243
Q

Titration

A

An experimental technique that lets you work out exactly how much alkali is needed to neutralise a quantity of acid

244
Q

Tollens’ reagent

A

A colourless solution of silver nitrate dissolved in aqueous ammonia which can be used distinguish between aldehydes and ketones

245
Q

Toxic substance

A

A substance that can cause illness or even death

246
Q

Transition metal

A

A metal that can form one or more stable ions with a partially filled d sub level

247
Q

Unsaturated fatty acid

A

A fatty acid that contains double bonds - found in oils

248
Q

Valid result

A

A result which answers the question it was intended to answer

249
Q

Variable

A

A factor in an experiment or investigation that can change or be changed

250
Q

Washing

A

A method of purifying a product by washing it with chemicals, such as washing with sodium hydrogen carbonate solutions to remove acids

251
Q

Water bath

A

A piece of equipment used to heat a reaction mixture, consisting of a container filled with water that can be heated to s set temp

252
Q

Weak acid / base

A

An acid or base that only partially dissociates in water

253
Q

Zwitterion

A

A dipolar ion which has both a negative and positive charge in different parts of the molecule

Chemistry (2017) (22 decks)

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