Chemistry Paper 2 OCR 2024 Exam Questions d d d d d d d
With Verified Answers d d
What two types of bond are within an alkene? - ANSWER:sigma and pi
d d d d d d d d d d d d
sigma bond - ANSWER:the direct overlapping of two orbitals
d d d d d d d d
pi bond - ANSWER:the sideways overlap of p orbitals
d d d d d d d d
C=C how many pi bonds and sigma bonds are in this - ANSWER:one sigma two pi bonds
d d d d d d d d d d d d d d d d
what two types of isomers are found in alkenes - ANSWER:cis/trans and E/Z
d d d d d d d d d d d d
Difference between E/Z isomers and Cis/trans isomers - ANSWER:E/Z compares relative
d d d d d d d d d d d
position based in priority groups (IP rules) look at the atomic number of the first bonded
d d d d d d d d d d d d d d d d
element d
Cis/Trans compares the relative positions of identical groups
d d d d d d d
major and minor products in alkenes - ANSWER:the major product forms the most stable
d d d d d d d d d d d d d d
carbocation intermediate during alkene reactions
d d d d
tertiary>secondary>primary
,what type of polymer do alkenes produce? - ANSWER:addition polymers
d d d d d d d d d
synthesis of an organic liquid - ANSWER:once reaction is complete into a separating funnel.
d d d d d d d d d d d d d d
Neutralise any excess acid using sodium carbonate (stops bubbling when all gone)
d d d d d d d d d d d d
Allow 2 layers to settle
d d d d d
Use density into to establish layers. If density into not given, add water to establish aqueous
d d d d d d d d d d d d d d d d
layer. d
(aqueous layer get bigger) d d d d
Density of water is 1 anything greater is more dense.
d d d d d d d d d
collect the organic layer d d d d
add a drying agent to remove small traces of water left in the organic layer (e.g.. anhydrous
d d d d d d d d d d d d d d d d d
CaCl2)
If the question tells you the boiling point of the organic liquid say distil dried product and
d d d d d d d d d d d d d d d d d
collect fraction that comes over the boiling point.
d d d d d d d
3 ways to determine purity of products - ANSWER:1. boiling point should match known data,
d d d d d d d d d d d d d d d
boils over a narrow range
d d d d d
or d
2. Run TLC, measure Rf value, compare to known data values/Run TLC and compare to
d d d d d d d d d d d d d d d
chromatogram of pure sample d d d
or d
3. Run NMR/IR/Mass spectrum, compare to spectral database of pure compounds.
d d d d d d d d d d
How to purify by recrystallisation? - ANSWER:-dissolve in a minimum volume of hot solvent
d d d d d d d d d d d d d
-cool in ice to recrystallise (impurities stay in solution)
d d d d d d d d d
-filter using Büchner flask/reduced pressure filtration
d d d d d
-wash with cold solvent d d d d
, -dry
Does reflux have an open or closed system? - ANSWER:open
d d d d d d d d d
overall equation for ozone depletion - ANSWER:O3 + O -> 2O2
d d d d d d d d d d
rate of formation of ozone = - ANSWER:rate of breakdown of ozone by UV light =
d d d d d d d d d d d d d d d
what type of compound breaks down the ozone layer? - ANSWER:chlorofluorocarbons
d d d d d d d d d d
Initiation reaction of CCl3F d d d d
what is the mechanism, equation and why the radicals formed - ANSWER:homolytic bond
d d d d d d d d d d d d d
fission d
Cl. + CCl2F.
d d d
C-Cl bond broken as its weaker than C-F
d d d d d d d
Evidence for the structure of delocalised benzene against the kekule structure - ANSWER:-Bond
d d d d d d d d d d d d d
lengths of benzene are the same
d d d d d d
-enthalpy of hydrogenation less exothermic than expected
d d d d d d d
-does not undergo addition reaction
d d d d
why does benzene need a halogen carrier to undergo electrophilic subsitution? - ANSWER:it is
d d d d d d d d d d d d d d
not electron dense enough to polarize the molecule into an electrophile
d d d d d d d d d d
electrophile - ANSWER:electron pair acceptor d d d d
what is the catalyst for halogenation of benzene? - ANSWER:AlX3
d d d d d d d d d
With Verified Answers d d
What two types of bond are within an alkene? - ANSWER:sigma and pi
d d d d d d d d d d d d
sigma bond - ANSWER:the direct overlapping of two orbitals
d d d d d d d d
pi bond - ANSWER:the sideways overlap of p orbitals
d d d d d d d d
C=C how many pi bonds and sigma bonds are in this - ANSWER:one sigma two pi bonds
d d d d d d d d d d d d d d d d
what two types of isomers are found in alkenes - ANSWER:cis/trans and E/Z
d d d d d d d d d d d d
Difference between E/Z isomers and Cis/trans isomers - ANSWER:E/Z compares relative
d d d d d d d d d d d
position based in priority groups (IP rules) look at the atomic number of the first bonded
d d d d d d d d d d d d d d d d
element d
Cis/Trans compares the relative positions of identical groups
d d d d d d d
major and minor products in alkenes - ANSWER:the major product forms the most stable
d d d d d d d d d d d d d d
carbocation intermediate during alkene reactions
d d d d
tertiary>secondary>primary
,what type of polymer do alkenes produce? - ANSWER:addition polymers
d d d d d d d d d
synthesis of an organic liquid - ANSWER:once reaction is complete into a separating funnel.
d d d d d d d d d d d d d d
Neutralise any excess acid using sodium carbonate (stops bubbling when all gone)
d d d d d d d d d d d d
Allow 2 layers to settle
d d d d d
Use density into to establish layers. If density into not given, add water to establish aqueous
d d d d d d d d d d d d d d d d
layer. d
(aqueous layer get bigger) d d d d
Density of water is 1 anything greater is more dense.
d d d d d d d d d
collect the organic layer d d d d
add a drying agent to remove small traces of water left in the organic layer (e.g.. anhydrous
d d d d d d d d d d d d d d d d d
CaCl2)
If the question tells you the boiling point of the organic liquid say distil dried product and
d d d d d d d d d d d d d d d d d
collect fraction that comes over the boiling point.
d d d d d d d
3 ways to determine purity of products - ANSWER:1. boiling point should match known data,
d d d d d d d d d d d d d d d
boils over a narrow range
d d d d d
or d
2. Run TLC, measure Rf value, compare to known data values/Run TLC and compare to
d d d d d d d d d d d d d d d
chromatogram of pure sample d d d
or d
3. Run NMR/IR/Mass spectrum, compare to spectral database of pure compounds.
d d d d d d d d d d
How to purify by recrystallisation? - ANSWER:-dissolve in a minimum volume of hot solvent
d d d d d d d d d d d d d
-cool in ice to recrystallise (impurities stay in solution)
d d d d d d d d d
-filter using Büchner flask/reduced pressure filtration
d d d d d
-wash with cold solvent d d d d
, -dry
Does reflux have an open or closed system? - ANSWER:open
d d d d d d d d d
overall equation for ozone depletion - ANSWER:O3 + O -> 2O2
d d d d d d d d d d
rate of formation of ozone = - ANSWER:rate of breakdown of ozone by UV light =
d d d d d d d d d d d d d d d
what type of compound breaks down the ozone layer? - ANSWER:chlorofluorocarbons
d d d d d d d d d d
Initiation reaction of CCl3F d d d d
what is the mechanism, equation and why the radicals formed - ANSWER:homolytic bond
d d d d d d d d d d d d d
fission d
Cl. + CCl2F.
d d d
C-Cl bond broken as its weaker than C-F
d d d d d d d
Evidence for the structure of delocalised benzene against the kekule structure - ANSWER:-Bond
d d d d d d d d d d d d d
lengths of benzene are the same
d d d d d d
-enthalpy of hydrogenation less exothermic than expected
d d d d d d d
-does not undergo addition reaction
d d d d
why does benzene need a halogen carrier to undergo electrophilic subsitution? - ANSWER:it is
d d d d d d d d d d d d d d
not electron dense enough to polarize the molecule into an electrophile
d d d d d d d d d d
electrophile - ANSWER:electron pair acceptor d d d d
what is the catalyst for halogenation of benzene? - ANSWER:AlX3
d d d d d d d d d
