Question Answer Marks AO
element Guidance
1 (a) (i)
Water flow AND condenser
Water in at bottom and out at top
AND condenser
Flask and technique
Pear-shaped/round-bottom flask
AND reflux
2 1.2 × 2
DO NOT AL
...
Question Answer Marks AO
element Guidance
1 (a) (i)
Water flow AND condenser
Water in at bottom and out at top
AND condenser
Flask and technique
Pear-shaped/round-bottom flask
AND reflux
2 1.2 × 2
DO NOT ALLOW conical flask, volumetric flask,
beaker in place of round bottom/pear shaped flask
Pear-shaped /
Round-bottom
flask
H432/03 Mark Scheme Oct 2020
7
Question Answer Marks AO
element Guidance
(ii) Diagram showing knowledge of filtration under
reduced pressure
Diagram showing Buchner flask
must have ONE side arm
AND
Buchner/Hirsh funnel on top of flask
Labels not required
----------------------------------
Further details:
• Funnel sealed or stoppered to flask
AND
• Apparatus capable of filtering under reduced pressure
AND
• Label for setup from side arm to indicate reduced
pressure
AND
• Label for Buchner flask OR Buchner/Hirsh funnel
ALLOW slips in spelling of ‘Buchner’
2
2.3
2.7
Labels NOT required for diagram
ALLOW diagram of a conical flask with a filtering
setup above
AND
Side arm either in conical flask OR between flask
and filter paper of funnel
IGNORE absence of seals
----------------------------------
MUST imply some type of seal between filter setup
and flask. ALLOW small gaps
Examples of suitable labels (may have arrow from
side arm or tube attached)
• to pump
• to vacuum
• air out
• suction
• reduced pressure
• etc.
For Buchner flask and Buchner funnel
DO NOT ALLOW just ‘flask OR ‘funnel’
Flask and funnel used in normal filtration
H432/03 Mark Scheme Oct 2020
8
Question Answer Marks AO
element Guidance
(b) (i)
Comparison of branching and points of contact
e.g. CH3CH2CH2NH2 has longer chain / straight
chain / no branches
AND
e.g. CH3CH2CH2NH2 has more points of contact /
more surface interaction (between molecules)
Relative strength of force
e.g. CH3CH2CH2NH2 has stronger/more
induced dipole(–dipole) interactions
OR London forces
--------------------------------------------------------------
Hydrogen bonds
CH3CH2CH2NH2 OR (CH3)2CHNH2 have
hydrogen/H bonds
OR
(CH3)3N has no hydrogen/H bonds
Relative strength of force
Hydrogen bonds are stronger than London forces
/permanent dipole interactions
------------------------------------------------------------------
Comparison of energy required to break force
e.g. More energy to break/overcome London
forces/intermolecular forces in CH3CH2CH2NH2
OR
More energy is needed to break H bonds (than
London forces)
5 →
4 max
1.2
2.1
1.2
2.1
ANNOTATE WITH TICKS AND CROSSES, etc.
------------------------------------------------------------------
ALLOW ORA throughout
ALLOW ‘The straighter the chain, the more points
of contact ….’
IGNORE comparison using ‘primary’, ‘secondary’
and ‘tertiary’.
Comparison of branching is required.
For London forces,
• ALLOW induced dipole(–dipole) interactions
• IGNORE IDID OR van der Waals’ forces/VDW
DO NOT ALLOW CH3CH2CH2NH2 has more
electrons
(number of electrons are the same)
DO NOT ALLOW ‘more energy to break covalent
bonds
ALLOW little energy is required to break London
forces (compared with H bonds)
H432/03 Mark Scheme Oct 2020
9
Question Answer Marks AO
element Guidance
(b) (ii) FIRST CHECK MOLECULAR FORMULA and
STRUCTURE
IF molecular formula = C5H13N AND correct structure
AND evidence of ideal gas equation → 6 marks
Correct up to 87 AND C5H13N → 5 marks
Correct up to 87 → 4 marks
--------------------------------------------------------------------------
Rearranging ideal gas equation
n = pV
RT
Unit conversion AND substitution into n = pV
RT :
• R = 8.314 OR 8.31
• V = 72(.0) × 10–6
• T in K: 373 K
e.g.
1.00 × 105 × 72.0 × 10–6
8.314 × 373
Calculation of n
n = 2.32 × 10–3 (mol)
Calculation of M
M =
0.202
2.32 × 10–3 = 87
Molecular formula
C5H13N
Molecular formula required
6
2.2×4
3.2
IF n = pV
RT is omitted, ALLOW when values are
substituted into rearranged ideal gas equation.
Calculator: n = 2.321740325 × 10–3 from 8.314
From 8.31, n = 2.322857889 × 10–3
ALLOW elements in any order
ALLOW molecular formula = C3H9N3
ALLOW other molecular formulae of an amine that
has M = 87, e.g. C4H9NO
H432/03 Mark Scheme Oct 2020
10
Question Answer Marks AO
element Guidance
Structure of amine A from C5H13N
OR
OR
OR OR
3.2 ALLOW any combination of skeletal OR structural
OR displayed formula as long as unambiguous
ALLOW structures below from
molecular formula = C3H9N3
ALLOW ECF but only if structure has calculated Mr
AND has 3 peaks in 13C NMR spectrum.
Use of
24000
3 marks max possible for use of 72.0 cm3 OR 0.720 dm3 by ECF
Calculation
e.g. n =
72.0
24000 = 3.00 × 10–3 No mark (calculation much simpler)
M =
0.202
3.00 × 10–3 = 67.3 OR 67 ECF
Molecular formula = C4H5N ECF
Structure
ECF
H432/03 Mark Scheme Oct 2020
11
Question Answer Marks AO
element Guidance
(c)
Organic product and water marked independently.
1st mark correct organic product OR water
IGNORE balancing numbers
2nd mark BOTH products AND correctly balanced.
2 3.2 ALLOW any combination of skeletal OR structural
OR displayed formula as long as unambiguous
ALLOW
NOTE: For ECF, any structure must have correct
number of bonds to C, H, O and N
DO NOT ALLOW structure of dimer
Question states molecular formula = C3H3NO
Total 16
H432/03 Mark Scheme Oct 2020
12
Question Answer Marks AO
element Guidance
2* Refer to marking instructions on page 5 of mark scheme for
guidance on marking this question.
Level 3 (5-6 marks)
Comprehensive explanation of the terms, ligand and
coordination number and ligand substitution
AND
3D diagrams of suitable examples of 6 AND 4 coordinate
complex ions with different shapes
AND
Ligand substitution illustrated with a balanced equation
There is a well-developed line of reasoning which is clear
and logically structured. The information presented is
relevant and substantiated.
Level 2 (3-4 marks)
Explanation of the terms, ligand and coordination number
and ligand substitution with some errors or omissions
AND:
Diagrams of suitable examples of 6 AND 4 coordinate
complex ions with different shapes
OR
A 3D wedged diagram of a suitable example of 6 OR 4
coordination
OR
A diagram of a suitable example of 6 OR 4 coordination
AND ligand substitution illustrated with an equation
OR
Ligand substitution illustrated with a balanced equation
There is a line of reasoning presented with some structure.
The information presented is relevant and supported by
some evidence
6 1.1×4
2.1×2
Indicative scientific points may include:
Terms
• Ligand: Donates a lone pair to metal ion
Forms dative covalent (coordinate) bond with metal ion
• Coordination number: Number of coordinate bonds
to metal ion. Could be implicit in annotated diagrams
NOTE: For monodentate ligands, ‘number of ligands’
is the same as the number of coordination number
• Ligand substitution: One ligand replacing another
Suitable examples of complex ions with different shapes
• Coordination no 6
Octahedral e.g. [Cu(H2O)6]
2+, [Fe(H2O)6]
3+
• Coordination no 4
Tetrahedral e.g. CuCl4
2–
, CoCl4
2–
OR Square planar Pt complexes, e.g. Pt(NH3)2Cl2
Diagrams and equations
• Diagrams of complex ions (may be 3D)
• Equation for ligand substitution
e.g. [Cu(H2O)6]
2+ + 4Cl– → CuCl4
2– + 6H2O
[Cu(H2O)6]
2+ + 4NH3 → [Cu(NH3)4(H2O)2]
2+ + 4H2O
NOTE: A clear and logically structured response
would link shapes with some of: coordination number,
names of shapes, connectivity, involvement of lone
pairs, bond angles, etc. (not inclusive)
ALLOW minor slips
NOTE: Levels and the mark within a level is a
‘best-fit’, not perfection
H432/03 Mark Scheme Oct 2020
13
Question Answer Marks AO
element Guidance
Level 1 (1-2 marks)
Explanation of some terms: ligand, coordination number and
ligand substitution with some errors or omissions.
AND
A suitable example of a complex ion OR Ligand substitution
illustrated with an equation with some errors
There is an attempt at a logical structure with a line of
reasoning. The information is in the most part relevant.
0 marks
No response or no response worthy of credit
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