25/11/2015
How to get that A* grade
in
Chemistry
There are now 32 Medical & 7 Veterinary
schools in the UK
A few years ago AAA – AAB would have
been the standard offer
In 2015 grades required range from
A*AAa to BBCb
Med schools asking for A* grades include:universities
state they require an A* grade
 Cambridge, Oxford, Birmingham, Exeter, Keele &
Plymouth

Most are now asking for 3 A levels plus a fourth AS
Typically AAAb

Most will not count General Studies

Be careful with Maths and Further Maths

Many will accept the Extended Project Qualification
(EPQ)

or Critical
Thinking
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As yet it is not totally clear but a consensus is beginning to
emerge
Almost all will
want at least
AAA at A level
All exams
must be taken
at one sitting
Almost all
want at least
B in a fourth
AS
Most will not
count
General
Studies
Must include
Chemistry
Many also
want Biology
You must do your
own research
Check the
universities you
are interested in
How to get information
Hull-York
Southampton
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How to get that A* grade
All papers will examine content from years 1 and 2
Every question on every paper has to have an assessment
objective - called AO AO1 AO2 AO3
Knowledge & understanding
30 – 35% of the marks
Application of knowledge
40 – 45% of the marks
Analysis, interpretation, evaluation 25 – 30% of the marks
To get an A* grade you will need to score 90%
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Exam papers will contain
Structured
questions
Free response questions
Multiple choice
questions
Questions will NOT be centred on
recall.
They will be based around:
 understanding
 application of knowledge
 problem solving
 more complex calculations




Need to stretch students even at AS
Students need to read beyond the core
syllabus
Use sources/questions that stretch them
Make absolutely certain the basics are well
understood
The real key to getting an A* grade is
to make sure that you know all the
routine stuff well, don’t make silly
mistakes and drop marks - develop
good exam technique
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
Oxygen, O2 – easy
O
O



Ozone, O3 – this now becomes A* material
and you have to apply your knowledge
Compound X has molar mass = 118 g mol-1
and contains 40.68%c, 5.08%H & 54.24%O.
Calculate its empirical & molecular formulae.
C
1
:
:
H
: O
1.5 : 1
Empirical formula = ?C2H3O2



Straight forward – often 80 -90% score the marks
But students will insist on rounding:
Compound X is a hydrocarbon with molar mass 68
g mol-1. It contains 88.24% carbon, deduce its
molecular formula.
C
88.24
:
H
11.76
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



A few years ago students were told the
formula of phosphoric acid, H3PO4 and asked
for the formula of calcium phosphate
Less than 10% got the correct response
I get the impression students don’t think its
particularly important if a formula is wrong
Use periodic table to deduce valency
Group
1
2
3
4
5
6
7
Valency
1
2
3
4
3
2
1
You also need to LEARN the valencies of a few common
transition elements and:
nitrate carbonate sulfate
Valency
ammonium
hydroxide
NO3
CO3
SO4
NH4
OH
1
2
2
1
1
1: Write each of the symbols
Ca
2: Write the valency at the top
right-hand side of the symbols
Ca
3: Cross-over the valencies. Write them
at the bottom right of the other symbol
Ca
4: You now have the formula of
the compound
OH
2
1
OH
( OH )
Ca(OH)2
Sli
de
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H 3PO4
Symbols on
both sides of
the equation
We have to balance:
We also have to balance:
Oxidation number
on each side of
the equation
IO3– + ...... I– + ...... H+
Charge on each
side of the
equation
...... I2 + ...... H2O
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




Lactic acid, CH3CH(OH)COOH is a naturally
occurring acid that reacts with NaOH(aq) to
produce the salt sodium lactate,
CH3CH(OH)COO-Na+.
Citric acid, HOC(COOH)3, is also a naturally
occurring acid and forms salts in the same way
as lactic acid.
Deduce the formula of sodium citrate.
Citric acid also reacts with calcium hydroxide.
Construct a balanced equation for the reaction.
 Rules







Elements: zero
Molecules add up to zero
Ions add up to the charge of the ion
Order of priority
Groups 1,2 & 3 are always +1, +2 and +3 respectively
Then apply in order F = -1, H = +1, O = -2, Cl = -1
You should then be able to calculate any others
+1
+1
-2 = 0
NaClO
It’s a molecule therefore adds up to zero
Apply the order of priority



Group 7 chemistry – students are expected to
know that Cl2 disproportionates.
Cl2 + 2NaOH  NaClO + NaCl + H2O
In a recent exam students were told that
under certain conditions Cl2 also reacted with
NaOH to form NaClO3 and then asked to
construct a balanced equation.
Cl2 +
NaOH  NaClO3 + NaCl
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
HNO3(aq) + Cu(s) → Cu(NO3)2(aq) + NO(g)+ H2O(l)


0.46g Na(s) reacts with 50 cm3 H2O(l). Calculate
the volume of H2(g) and the concentration of
the NaOH(aq) solution produced.
40 cm3 of a hydrocarbon was ignited with 500 cm3 of
O2(g) and the products cooled to room temperature.
The resultant gas mixture, 420 cm3, was passed
through a solution of NaOH(g) and the volume of gas
dropped to 260 cm3. Determine the molecular
formula of the hydrocarbon?
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%
chlorine atoms
75%
easy!!
25%
35
37
m/z
(35 x 75) + (37 x 25) = 2625 + 925 = 3550 = 35.5
100
100
100
BUT





It will not be based on recall
It might be mathematically based
It might be an extension of the syllabus
content
It might be based on information given
The next questions aren’t on the syllabus but
you are supplied with enough information to
answer the question
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
Carbonyl compounds that have at least one
H on a C adjacent to the C=O can undergo a
condensation reaction.
+
C
H 3C
OH
O
O
CH
3
H 3C
N aO H
cat
C
CH
3
Propanone

H 3C
O
C
CH
CH
2
C
CH
3
3
2-methyl-2-hydroxypentan-4-one
Use this information and your knowledge of
other reactions to suggest how ethanal
could be converted into butane-1,3-diol.
GOOD EXAM TECHNIQUE
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Book 1 covers modules
1 to 4 which are taught
in the first year of the
course
Revision guide –
summarises essential
topics and provides
insight into what
examiners are looking
for.
Practice questions
that cover the
syllabus topic by topic
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At the end of each chapter there are
practice questions which are graded
as:
*
easy,
**
moderate,
***
difficult
****
challenging
If you can do this in your head
….. you
are better
thantoI am
Multiple choice
questions
are new
most of the exams and there aren’t
You have to practice questions
a lot of old questions to practice.
At the end of each chapter there
are 10 multiple choice questions to
try/practice.
In the two textbooks there are over 300 multiple choice
questions to try.
Other sources of help
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Each question is worth 1 mark
There are around 27 questions & only
30 minutes to answer them all
And you cannot use a calculator

Our genes evolved for a Stone Age life style. Therefore,
we must adopt Stone Age habits if we are to be healthy.

Write a unified essay in which you address the following:
Explain the logical connexion between the two sentences.
What might be the practical implications if we were to agree
with the reasoning?
Discuss the extent to which the argument is valid.



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