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29 SEP 2018
So you’ve had the bright idea of signing up for the Cambridge International A Level Chemistry examinations.
Was it a mistake?
This blog will go through the basic information as well as the little extra that you need in order to make the most of, and get the most enjoyment and success out of, A Level Chemistry, which can be a rewarding subject.
A solid chemistry knowledge and skill base, the way the subject teaches you to think in a logical manner, and of course your actual external marks are important and open up endless possibilities in your education journey.
This could be whether you are considering applying to overseas universities which recognise and respect CIE examinations, applying to undergraduate or postgraduate medical degrees, or for any science-based tertiary study.
The University of Cambridge International Examinations are external examinations ranging over 50 subjects, which are chosen as either part of or to wholly make up the central curriculum by 10,000 high schools in 160 countries worldwide.
The qualification is recognised by all UK universities and valued universities around the world, including the US.
The exams for a level, e.g. AS are held in either a “summer” (UK summer) “May/June (M/J)” series or a “winter” “October/November (O/N)” series.
AS Level is the first half of the A Level, which consists of both AS and A Level examination series. AS Chemistry can be used as a standalone qualification.
While you can sit all the AS and A2 papers which would lead to an A Level in one series e.g. O/N 2018, this would be a super intense exam series as most people do at least three other subjects at the same time.
Thus, most students/schools choose to do the AS and A2 papers one year after the other, culminating in the A Level. The above, common progression through the A Level has the benefit of a safety net - if you somehow mess up one paper in AS, or simply do not achieve to the level you you wanted, there is no need to stress!
Although you will have to pay again, you can sign up for M/J resit, e.g. M/J 2019 in the above example, where you’ll have the chance to make amends.
Also, the AS papers lose half their weighting when part of a whole A Level, so you can raise your mark through the A2 papers.
The step up from IGCSE to AS is a significant jump in skills, content and analysis, whereas the step up from AS to A2 is not so big, and is arguably based more in content.
The A2 papers are commonly and confusingly referred to as simply A Level, due to the fact that if you are sitting this level, you have passed or are sitting AS in the same series.
The syllabus (code 9701), which can be found here is a document which contains information about the equipment, content and resources students and teachers require to sit and teach the A Level.
Section 3.2 contains Subject Content. The AS papers only assess the non-bolded content in this section, whereas A Level papers assess both the bolded and non-bolded content.
A level Chemistry consists of five papers: three at AS level and two at A2 level.
Paper 1 (AS): Multiple Choice
Content: 40 Multiple Choice Qs based on AS syllabus content Duration: 1 hour Marks: 40 Weighting AS, A2: 31%, 15.5%
Comment: this is often regarded as harder than paper 2 and will probably separate the top candidates.
It is difficult due to the depth of understanding required to not be tempted by familiar, incorrect options, as well as the time pressure.
Paper 2 (AS): AS Level Structured Questions
Content: Varying number of short-answer Qs based on AS syllabus content Duration: 1 hour 15 minutes Marks: 60 Weighting AS, A2: 46%, 23%
Comment: content knowledge is most important for this paper, as well as a strong idea of what the examiners require in answers, which will be covered later.
Paper 3 (AS): Advanced Practical Skills
Content: Two or three experiments within content scope indicated in syllabus Duration: 2 hours Marks: 40
Weighting AS, A2: 23% 11.5%
Comment: this paper builds on skills developed through school labs e.g. ability to carry out a titration so pay attention rather than hijacking your mate’s experiment in class!
This paper would be difficult if you were to self-study AS Chemistry.
It is notorious for causing people to panic and not attempt some questions due to time pressure. However, don’t stress, past papers and practice are extremely helpful.
Paper 4 (A2): A Level Structured Questions
Type: Varying number of short-answer Qs based on A level content (bold) Duration: 2 hours Marks: 100 Weighting A2: 38.5%
Comment: this paper often tests some AS topics like the more simple enthalpy reactions are often examined and require looking back on some AS notes.
Paper 5 (A2): Planning, Analysis and Evaluation
Type: Varying number of short-answer Qs on practical content
Duration: 1 hour 15 minutes Marks: 30 Weighting A2: 11.5%
Comment: students often find this A2 paper easier than the AS practical skills paper, as you do not have to carry out the finicky details of a practical experiment yourself, but mostly plan and analyse experiments and findings.
Papers 1, 2 and 4 consist of a mixture of “Knowledge with understanding” as well as “Handling, applying and evaluating information”. The practical papers 3 and 5 consist of “Experimental skills and investigations” but also test and assume knowledge of the content base of the syllabus.
Should you even write notes?
Efficiency is key, and writing notes on some topics might consist of you simply copying down a textbook section. In these cases, it would pay to simply refer to the textbook or maybe photocopy the relevant section.
However, note-taking is often essential to summarise and elaborate on content in order to better understand and memorise details when studying.
Handwritten or computer?
Writing equations and drawing diagrams can be tedious on a Word or Google doc, so unless you are highly skilled at computer note-taking, I would recommend hand-writing notes and developing a colour coded system, e.g. red writing for keywords, etc.
Your method of note-taking should be methodical, and should roughly follow these steps:
Firstly, have the syllabus section 3.2 Subject Content handy when writing notes. Choose a section you are going to focus on.
E.g. Within section 3.2, sub-section 4 “States of Matter” we would start with: 4.1 “The gaseous state: ideal and real gases and pV = nRT” then look at “state the basic assumptions of the kinetic theory as applied to an ideal gas”
Take out any notes your teachers may have given you, as well as your textbook either set by your school, or which you have purchased after locating the recommended texts through the CIE website “Published Resources” link.
Furthermore, resources such as Khan Academy videos, Royal Society of Chem videos and websites such as Chemguide can provide additional information and visual cues for you to add to notes.
Write notes that address the syllabus sentence from the relevant resource sections. Note that there is often some extra contextual information that may be gathered from the textbook and notes.
E.g. The ideal gas is merely a theoretical construct, and no such gas exists in real life. However, many real gases exhibit behaviour which approximates to an ideal gas.
The assumptions of the kinetic theory as applied to an ideal gas are as follows:
Gas particles (atoms or molecules) are constantly in random motion in straight lines. There are negligible intermolecular forces of attraction between gas molecules. Collisions between gas molecules are perfectly elastic. The gas molecules occupy a negligible volume relative to the volume of a container.
N.B it is always useful to draw rough diagrams for concepts in chemistry.
Now to study and memorise your notes.
The most efficient and powerful way to memorise is through practice recall.
To do this, simply read the syllabus sentence, and try to recall the points, equations and diagrams you made in the notes.
Once you know the content well, and attempt some practice questions as well as referred to marking schemes for these, you may come across keywords or facts that you must have in your answer to get the marks.
Highlight these or if they’re new add these in!
For example, perhaps you found that in a past question testing the ideal gas assumptions, to get the mark for stating point 3, you must add the fact that “there is no loss of kinetic energy due to collisions between gas molecules”.
Point 3 now becomes:
For all these papers, practising questions after you have a strong knowledge base is crucial to understand how to answer questions, and you can locate past papers for each of the five on the CIE website link shared above.
The first number of the paper e.g. 1 in 13 means it is a variant of paper 1, as variants in different exam centres are used to avoid leaking of answers. Make sure the syllabus code (9701) is correct.
S or W mean summer or winter series. E.g. 9701_w17_qp_12.pdf = paper 1 O/N (winter) 2017.
“Marking schemes (ms)” give you the correct answers. These are vital to get to know which keywords and style of answers the examiners are after!
“Examiner’s reports (er)” are helpful to see where students went wrong and get explanations for answers.
“Grade thresholds (gt)” help you see what grade a raw mark equates to.
For example, from gt for O/N 2017, a raw mark over all the A Level papers averaging 69% raw translated into an 80% A, while a 78% raw, translated into a 90% A final mark!
The Data Booklet, of which a specimen can be found here, is a short booklet which accompanies the question paper in every exam.
It contains information including the periodic table, i.e. the table of the elements with their atomic number, symbol and mass, as well as other information such as bond energies crucial to answering questions.
The following sample A Level Chemistry question will demonstrate how the data booklet could be used.
Calculate the amount of energy that is given out as a result of this chemical reaction (the enthalpy change):
2H2 (g) + O2 à 2H2O(l)
Now we go to the Data Booklet, to the “Bond Energies” section.
Locate the bond energies for H-H (436 kj mol-1), O=O (496 kj mol-1), and H-O (460 kj mol-1), as these are the bonds broken and formed.
Therefore, energy absorbed (bonds broken) = energy from 2H-H + 2O=O bonds = 2 x 436 + 496 = 1386 kJ
Energy released (bonds formed) = 4H-O = 4 x 460 = 1840 kJ
Enthalpy change = ∆H = 1368 - 1840 kJ = -484 kJ
You will know from your studies that a negative ∆H is an exothermic reaction, and thus 484 kj is released.
A Level Chemistry is often regarded as one of the more difficult subjects due to sheer breadth of content. However, although A Level Chemistry seems daunting, there is no need to fear.
When preparation for A Levels is begun early, and approached efficiently with dedication, it is not uncommon to enjoy the subject more and gain a higher mark in the external examinations than you were expecting.