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Chemistry A2 > Chemistry A2 > Flashcards

Chemistry A2 Flashcards

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1
Q

In terms of B-L theory, what is an acid?

A

A proton donor

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2
Q

In terms of B-L theory, what is a base?

A

A proton acceptor

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3
Q

What holds ions together in a lattice?

A

Electrostatic attraction

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4
Q

What kind of structure do metals have?

A

Giant metallic lattice structures

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5
Q

Melting and boiling points of ionic lattices

A

High

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6
Q

What is STP?

A

Standard temperature and pressure

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7
Q

Typical state of ionic lattice at STP?

A

Solid

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8
Q

Does solid ionic lattice conduct electricity?

A

No

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9
Q

Does ionic liquid conduct electricity?

A

Yes

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10
Q

Is ionic lattice soluble in water?

A

Yes

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11
Q

Melting/boiling points of simple molecular?

A

Low

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12
Q

Typical state of simple molecular at STP?

A

Sometimes solid, usually liquid or gas

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13
Q

Does solid simple molecular conduct electricity?

A

No

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14
Q

Does liquid simple molecular conduct electricity?

A

No

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15
Q

Is simple molecule soluble in water?

A

Depends how polarised the molecule is

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16
Q

Melting/boiling point giant molecular?

A

High

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17
Q

Typical state of giant molecular at STP?

A

Solid

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18
Q

Does giant molecular conduct electricity when solid?

A

No (expect graphit)

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19
Q

Does giant molecular conduct electricity when liquid?

A

Generally sublimes so no

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20
Q

Does giant molecular dissolve?

A

No

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21
Q

Melting/boiling points of metallic?

A

High

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22
Q

State of metallic at STP?

A

Solid

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23
Q

Does solid metallic conduct electricity?

A

Yes

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24
Q

Does liquid metallic conduct electricity?

A

Yes

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25
Q

Does metallic dissolve in water?

A

No

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26
Q

Do lone and bonding pairs repel the same?

A

No - lone pairs more

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27
Q

Shape of 2 electron pairs on central atom?

A

Linear molecules

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28
Q

Shape of 3 electron pairs on central atom?

A

Trigonal planar

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29
Q

Shape of 4 electron pairs on central atom?

A

Tetrahedral, trigonal pyramidal, bent

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30
Q

Shape of 5 electron pairs on central atom?

A

Trigonal bipyramidal

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31
Q

Shape of 6 electron pairs on central atom?

A

Octahedral

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32
Q

Bonding angle linear?

A

180*

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33
Q

Bonding angle trigonal planar?

A

120*

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34
Q

Bonding angle tetrahedral?

A

109*

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35
Q

Bonding angle trigonal pyramidal?

A

107*

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36
Q

Bonding angle trigonal bipyramidal?

A

90* and 120*

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37
Q

Bonding angle octahedral?

A

90*

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38
Q

What makes an alcohol primary/secondary/tertiary?

A

Primary - 1 C bonded to C OH is on
Secondary - 2 Cs bonded to C OH is on
Tertiary - 3 Cs bonded to C OH is on

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39
Q

Naming diols?

A

alkane-numbers-diol including e!!

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40
Q

Ether group?

A

-O-

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41
Q

Naming ethers?

A

alkOXYalkane (long then short)

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42
Q

Amine group?

A

NH2

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43
Q

Naming diamine?

A

[numbers]-diamino[alkane]

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44
Q

Ester group?

A

-COO-

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45
Q

Naming esters?

A

[alcohol]yl [alkane]oate

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46
Q

Aldehyde group?

A

-COH

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47
Q

Aldehyde naming?

A

[alkan]al

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48
Q

Ketone group?

A

R-CO-R’

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49
Q

Ketone naming?

A

[alkan]one

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50
Q

Mechanism of reaction Alkene -> Poly(alkene)?

A

Free radical polymerisation

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51
Q

Reagents/conditions Alkane -> Alkene?

A

Hydrogen gas, Nickel catalyst, 150C, high pressure
or
Platinum catalyst, 20C, high pressure

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52
Q

Reagents/conditions Alkene -> Bromoalkene?

A

HBr, 20*C

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53
Q

Reagents/conditions Alkene -> Dibromoalkene?

A

Br2, 20*C

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54
Q

Mechanism of alkene reactions?

A

Electrophilic addition

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55
Q

Reagents/conditions Alkene -> Alcohol?

A

Steam, 300*C, H3PO4 catalyst
or
Water, conc H2SO4 catalyst

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56
Q

Reagents/conditions Alcohol -> Alkene?

A

Al2O3 at 400*C
or
Reflux with conc. H2SO4

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57
Q

Type of reaction Alcohol -> Alkene?

A

Dehydration

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58
Q

Reagents/conditions Tertiary Alcohol -> Chloroalkane?

A

Shake with conc. HCl at room temp

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59
Q

Reagents/conditions Chloroalkane -> Amine?

A

Reflux with excess NH3 in ethanol solvent

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60
Q

Reagents/conditions Chloroalkane -> Alcohol?

A

Reflux with aqueous NaOH

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61
Q

Mechanism reaction Chloroalkane -> Alcohol?

A

Nucleophilic subsitution

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62
Q

Reagents/conditions Alcohol -> Ketone?

A

Reflux secondary alcohol with acidified potassium dichromate

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63
Q

Formula potassium dichromate?

A

K2Cr2O7

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64
Q

Reagents/conditions Alcohol -> Carboxylic Acid?

A

Reflux primary alcohol with acidified potassium dichromate

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65
Q

Reagents/conditions Alcohol -> Aldehyde?

A

Distill primary alcohol with acidified potassium dichromate

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66
Q

Reagents/conditions Aldehyde -> Carboxylic Acid?

A

Reflux with acidified potassium dichromate

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67
Q

Carboxylic Acid + Alkali -> ?

A

Salt + Water

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68
Q

Carboxylic Acid + Carbonate -> ?

A

Salt + Carbon Dioxide + Water

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69
Q

Alcohol + Carboxylic Acid -> ?

A

Ester

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70
Q

Reagents/conditions for Alcohol + Carboxylic Acid -> Ester?

A

Acid catalyst, usually conc. H2SO4

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71
Q

How do you test for phenol?

A

Shake with Iron(III) Chloride solution, turns purple

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72
Q

Phenol + Strong Base -> ?

A

Salt + Water

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73
Q

Acyl chloride group?

A

-COCl

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74
Q

Name acyl chloride?

A

[alkan]oyl chloride

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75
Q

Acyl Chloride + Phenol -> ?

A

Ester + HCl gas

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76
Q

HCN + Carbonyl compound -> ?

A

Cyanohydrin

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77
Q

What is a cyanohydrin?

A

A molecule with a CN and an OH group

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78
Q

Mechanism of cyanohydrin?

A

Nucleophilic addition reaction

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79
Q

What is a nucleophile?

A

Donates an electron pair to form a bond

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80
Q

What is an electrophile?

A

Accepts an electron pair to form a bond

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81
Q

Different types of reaction?

A

Rearrangement, addition, substitution, elimination, condensation

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82
Q

Different between elimination and condensation?

A

Elimination starts with 1 molecule, condensation with 2

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83
Q

What three questions do drug trials answer?

A

Is it safe?
Does it work?
Is it better than any current alternatives?

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84
Q

What energy does IR increase?

A

Vibrational

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85
Q

Two ways of making chromatography spots visible?

A

Plates with fluorescent dye added. Spots of chemical cover this, the rest glows under UV

Expose to iodine vapour, sticks to chemicals and shows up as purple spots

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86
Q

What is Rf value?

A

distance travelled by spot/distance travelled by solvent

Constant for each chemical so can be used to identify it

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87
Q

What can change Rf value?

A

Composition of TLC plate, the solvent, temperature

88
Q

How can you work out the mass of a ‘lost’ mass spec fragment?

A

Difference between peaks

89
Q

What is an amine?

A

Ammonia with one or more H atoms replaced by R group
One replace = primary
Two replaced = secondary
Three replaced = tertiary

90
Q

Naming amines?

A

Amino[alkane]

91
Q

Is an amine an acid, base or neither?

A

Base

92
Q

Amine + Acid -> ?

A

Salt

93
Q

What is an amide?

A

Contains group -CONH2

94
Q

What is acylation?

A

Addition of an acyl group to a molecule [-C(-R)=O]

95
Q

Amine + acyl chloride -> ?

A

N-substituted amine + HCL

96
Q

What happens to the HCL formed as a byproduct of acylation of an amine?

A

Reacts with any remaining amine to for a salt

97
Q

Products of hydrolysis of amides under acidic conditions?

A

Carboxylic acid and ammonium salt

98
Q

Products of hydrolysis of amides under basic conditions?

A

Carboxylate ion and ammonia gas

99
Q

Products of hydrolysis of ester under acidic conditions?

A

Acid and alcohol

100
Q

Conditions for hydrolysis of ester under acidic conditions?

A

Reflux with dilute acid

101
Q

Products of hydrolysis of ester under basic conditions?

A

Carboxylic acid salt and alcohol

102
Q

Conditions for hydrolysis of ester under basic conditions?

A

Reflux with dilute alkali

103
Q

How do you purify an organic solid?

A

Recrystallisation

104
Q

How does recrystallisation take place?

A

1) Very hot solvent added to impure solid to the point it just dissolves
2) Gives saturated solution of impure product
3) Left to cool - forms crystals as it does
4) Impurities stay in solution
5) Crystals removed by filtration

105
Q

What are the requirements of a solvent for recrystallisation?

A

Substance must be very soluble in hot solvent but nearly insoluble in cold solvent

106
Q

What forms addition polymers?

A

Alkenes

107
Q

What forms condensation polymers?

A

Two different types of monomer with at least two functional groups each that lose a water molecule for each bond formed

108
Q

Product of dicarboxylic acids and diamines?

A

Polyamides

109
Q

Product of dicarboxylic acids and diols?

A

Polyesters

110
Q

What is an amide link?

A

-C(=O)-N-H-

111
Q

What is an ester link?

A

-C(=O)-O-

112
Q

Principles of green chemistry?

A
  • Use reactants as safe and environmentally friendly as possible
  • Use as few other materials, like solvents, as possible
  • Use renewable raw materials where possible
  • Keep energy use to minimum
  • Generate no waste products hazardous to human health or environment
113
Q

How does recycling and reusing polymers reduce CO2 emissions?

A
  • Less energy required for high temp/pressure requirements of process therefore burns less fossil fuels
  • Less landfill
114
Q

Advantage of recycling plastics?

A

Reduce need for production of more

115
Q

Disadvantage of recycling plastics?

A

Sorting and processing uses lots of energy

116
Q

Advantage of burning plastics?

A

Reduces landfill

Generates heat -> electricity

117
Q

Disadvantage of burning plastics?

A

Produces CO2 and some toxic waste gases

118
Q

Properties of longer chain plastics?

A

Stronger and less flexible because more intermolecular bonds between chains

119
Q

What is Tm?

A

Melting point of a thermoplastic

120
Q

What are thermoplastics?

A

Don’t have any covalent bonds or cross links between molecules

121
Q

What happens to a thermoplastic heated above Tm?

A

It will soften and then melt

122
Q

What is Tg?

A

Glass transition temperature

123
Q

What happens when a thermoplastic is cooled below Tg?

A

It will be brittle so snap or shatter

124
Q

What are crystalline polymers?

A

Arrangement of chains is ordered

125
Q

What are amorphous polymers?

A

Arrangement of chains is random

126
Q

Which is stronger? Crystalline or amorphous polymers?

A

Crystalline because neatly ordered so closer together and stronger intermolecular forces

127
Q

How do you modify a polymer to meet your needs?

A

Copolymerisation
Plasticiser
Cold-drawing

128
Q

What is copolymerisation?

A

Making a polymer using a mixture of monomers

129
Q

What is the use of a plasticiser?

A

Makes a polymer bendier by getting between chains and pushing them apart

130
Q

What is cold-drawing?

A

Increases crystallinity of a polymer. Chains are pulled out in straight lines so chains lie closer together

131
Q

Ways of measuring reaction rate?

A
  • pH measurement
  • Gas volume
  • Loss of mass
  • Colour change
  • Titration
132
Q

What does zeroth order with respect to a reactant mean?

A

If you double a reactant’s concentration, the rate stays the same

133
Q

What does first order with respect to a reactant mean?

A

Double the reactant’s concentration, the rate also doubles

134
Q

What does second order with respect to a reactant mean?

A

Double the reactant’s concentration, the rate quadrouples

135
Q

What is the rate equation?

A

=k[A]m[B]n

136
Q

What is the overall order of a reaction?

A

Sum of each individual order

137
Q

What is ‘k’ in the rate equation?

A

Rate constant: bigger = faster reaction

138
Q

How is the rate constant affected by temperature?

A

Higher temperature = higher rate constant

139
Q

How do you calculate initial rate?

A

Find the gradient of the tangent at time = 0

140
Q

How can you determine order of reaction?

A

Experimentally by:

  • Finding rate equation using initial rates
  • Half lives from concentration-time graph
141
Q

How do you determine order of reaction using half lives?

A

If the rate doesn’t change it’s zero order
If the rate changes and the half life value is constant it’s first order
If the rate changes and the half life increases it’s second order

142
Q

What is the rate-determining step?

A

The step of a reaction with the slowest reaction rate

143
Q

How do you know if a reactant is part of the rate determining step?

A

If it’s in the rate equation, it affects rate so it or a derivative must be
If it’s not in the rate equation, it can’t be involved

144
Q

What does the rate equation show about the number of molecules in the rate determining step?

A

The order of reaction shows the number of molecules of each type in the rate determining step

145
Q

How can you predict the rate equation from the rate determining step?

A

If you know it, you know each reactant must be in it and the order will be the same as the number of molecules of each

146
Q

What is happens to order in enzyme-catalysed reactions?

A

It changes as substrate is added, eventually becoming zero order as the reaction can go no faster

147
Q

What are the steps on an enzyme catalysed reaction?

A

S + E -> ES
ES -> EP
EP -> E + P

148
Q

Which is the rate determining step in an enzyme catalysed reaction?

A

Step 1 to start with, until no more enzyme is free to form ES complex. At this point, step 2 becomes rate determining

149
Q

What does an amino acid contain?

A

Amino group, carboxyl group, H atom, variable group - all around central carbon atom

150
Q

What is a zwitterion?

A

A dipolar ion - has both positive and negative charge in different parts

151
Q

What is the isoelectric point of an amino acid?

A

The pH at which the average overall charge on the amino acid is zero - this is when zwitterions can exist

152
Q

What happens when conditions are more acidic than isoelectric point?

A

NH2 group is likely to be protonated (N+)

153
Q

What happens at the isoelectric point?

A

Zwitterion forms
NH2 is protonated (N+)
Carboxyl is negative (-O minus)

154
Q

What happens what conditions are more basic than isoelectric point?

A

-COOH group likely loses a proton (-O minus)

155
Q

How to identify amino acids in chromatography?

A

Spray with ninhydrin solution and they turn purple

156
Q

How do proteins form?

A

Condensation polymers of amino acids

157
Q

What is primary structure?

A

Sequence of amino acids in the polypeptide chain

158
Q

What is the peptide bond?

A

CONH

159
Q

What is secondary structure?

A

The shape of the chain - a-helix or b-pleated sheets

160
Q

What is tertiary structure?

A

The 3D shape formed by extra bonding within the polypeptide chain

161
Q

What holds secondary structure together?

A

Hydrogen bonds

162
Q

What holds tertiary structure together?

A
  • I-I dipole forces
  • Ionic interactions between side groups
  • Hydrogen bonding
  • Disulfide bridges
163
Q

What makes up a nucleotide?

A

Phosphate group, pentose sugar, base

164
Q

How does the sugar-phosphate backbone form?

A

Condensation polymerisation

165
Q

How does a base connect to its sugar?

A

Condensation reaction

166
Q

How do enzymes improve green chemistry?

A
  • Reduce temperatures
  • Increase yields
  • Less unreacted waste chemicals
167
Q

What is a structural isomer?

A

Same molecular formula but atoms are arranged in a different way

168
Q

What is a stereoisomer?

A

The orientation of atoms in space is different - E/Z and optical isomers

169
Q

What is E/Z isomerism?

A

Isomerism due to no rotation around a double bond.

170
Q

What are optical isomers?

A

Isomers that are mirror images of each other. Non-superimposable. Around a chiral carbon

171
Q

What is a chiral carbon?

A

Has four different groups attached to it

172
Q

Other name for optical isomers?

A

Enantiomers

173
Q

What colour are manganate (vii) ions in aqueous potassium manganate (vii)?

A

Purple

174
Q

What is a manganate(vii) ion?

A

MnO4-

175
Q

What does a reducing agent do?

A

Donates some of its electrons to reduce something

176
Q

What does an oxidising agent do?

A

Takes electrons away from something else to oxidise it

177
Q

Oxidation state of uncombined chemicals?

A

0

178
Q

Oxidation state of elements bonded to identical atoms? E.g. O2

A

0

179
Q

Oxidation state of a simple monatomic ion? E.g. Na+

A

Same as its charge

180
Q

Why must manganate ions be acidified to work as an oxidising agent?

A

So H+ ions can react with O2- ions when it is reduced

181
Q

What kind of electrode do you use for different ions of the same element as a half cell?

A

Platinum or graphite - must conduct electricity and be inert so as not to react with the half cell contents

182
Q

What is standard electrode potential?

A

The voltage of a half cell measured under standard when the half cell is connected to a standard hydrogen electrode

183
Q

What are standard conditions for a half cell?

A

Solutions all 1moldm-3
Temp 25*C
Pressure 100kPa

184
Q

Which metal is oxidised in an electrochemical cell?

A

The one with the most negative standard electrode potential

185
Q

How do you calculate the cell potential?

A

E* more pos. - E* more neg

186
Q

How do you know if a redox reaction is feasible?

A

If the standard electrode potential for what is being reduced is more positive, the reaction could take place

187
Q

What are the steps of rusting?

A

1) 2H2O + O2 + 2Fe -> 2Fe2+ + 4OH-
2) Fe2+ + 2OH- -> Fe(OH)2
3) 2H2O + O2 + 4Fe(OH)2 -> 4Fe(OH)3
4) Gradually turns to hydrated iron(iii) oxide, Fe2O3.xH2O

188
Q

What methods prevent rusting?

A

Barriers and sacrificial method

189
Q

What barriers can prevent rusting?

A

Painting/coating with polymer

Oiling/greasing

190
Q

What is he sacrificial method of preventing rusting?

A

Place a more reactive metal over the iron. Water react with this instead of iron. Often Zinc.

191
Q

What is galvanising?

A

Spraying zinc over an object

192
Q

Process of iron recycling?

A
  • Magnet used to separate iron from other stuff
  • Melted in furnace, oxygen blown through to burn off impurities
  • More iron and steel added to stop it getting too hot as burning off is exothermic
  • Carbon and other elements added to obtain steel with exactly the desired properties
193
Q

What is steel?

A

Alloy of iron and carbon

194
Q

How are metals extracted from their ores?

A

Reduction by:
Heating with carbon
Reaction with more reactive metal
Electrolysis

195
Q

How does reduction by heating with carbon work?

A

Carbon is oxidised, but doesn’t work with reactive metals

196
Q

How does reduction by reaction with a more reactive metal work?

A

Very reactive metals are powerful reducing agents

197
Q

How does electrolysis work in extraction of metals?

A

Electric current passed through molten ore. Impurities collect below impure metal electrode, pure metal collects on negative electrode.

198
Q

Which block are the transition elements?

A

D

199
Q

What is a transition metal?

A

A metal that can form at least one stable ion with an incomplete d-subshell

200
Q

Which elements fill subshells strangely?

A

Chromium and copper, both of which only fill up to 1 in 4s

201
Q

What order are electrons lost in?

A

4s first

202
Q

What are the properties of transition elements?

A

1) Can form complex ions
2) Can exist in variable oxidation states
3) Form coloured ions
4) Good catalysts because they can change oxidation states

203
Q

What are complex ions?

A

Metal ions surrounded by ligands.

204
Q

What is a ligand?

A

Any ion or molecule that forms a coordinate bond with a metal ion

205
Q

What is a coordinate bond?

A

A dative covalent bond

206
Q

What is the coordination number?

A

The number of coordinate bonds formed with the central metal ion (usually 4 or 6)

207
Q

What is ligand substitution and what is a usual indicator?

A

Ligands exchanging places. There is normally a colour change.

208
Q

Product and colour change of:

[Fe(H2O)6]2+ + 2OH- -> ?

A

[Fe(H2O)4(OH)2] + 2H2O

Green solution to green precipitate

209
Q

Product and colour change of:

[Fe(H2O)6]3+ + 3OH- -> ?

A

[Fe(H2O)3(OH)3] + 3H2O

Orange/brown solution to rust-brown precipitate

210
Q

Product and colour change of:

[Cu(H2O)6]2+ + 2OH- -> ?

A

[Cu(H2O)4(OH)2] + 2H2O

Pale blue solution to blue precipitate

211
Q

Product and colour change of:

[Cu(H2O)6]2+ + 2NH3 -> ?

A

[Cu(H2O)4(OH)2] + 2NH4+

Pale blue solution to blue precipitate

212
Q

Product and colour change of:

[Cu(H20)6]2+ + 4NH3 -> ?

A

[Cu(NH3)4]2+ + 6H2O

Pale blue solution to intense blue solution

213
Q

What is a homogeneous catalyst?

A

In the same phase as the reactant chemicals

214
Q

Why are transition metals good homogeneous catalysts?

A

They can easily be both oxidised and reduced, so can take electrons from one chemical and give them to another

215
Q

What is a heterogenous catalyst?

A

In a different phase from the reactants

216
Q

Why are transition metals good heterogenous catalysts?

A

They can use their s- and d- orbitals for bonding to the reactant molecules

217
Q

Salters definition of enantiomer?

A

Isomers whose structures are mirror images and non superimposable

Chemistry A2 (2 decks)

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