6 Tips to Ace Your 'A' Level Chemistry
Tip #01 - Understand AND memorise key definitions, equations and concepts.
Tip #01 is of fundamental importance. Working on the other tips without fulfilling Tip #01 will gain you limited results.
But I got an A for my 'O' levels by ‘memorising without understanding’ or ‘understanding without memorizing’.
'A’ level Chemistry is much more rigourous so your ‘cheat codes’ will no longer work. Ask your seniors if you don’t believe.
But my teacher say understanding is more important than memorising.
That is true in scientific research or when solving real life problems where information can be googled and there isn’t much of a time constraint. Under the conditions of a traditional pen-and-paper assessment, memorising is just as, if not more important.
Duh, isn’t Tip#01 obvious?
Yes it is! But ask yourself if you have done it. More often than not, students go into a test/ exam with only a fuzzy impression of the content hoping that it will miraculously crystallise on seeing the questions.
Note that you should only memorise KEY definitions, equations and concepts. If you have issues with putting your understanding in words, you may also want to memorise short phrases/ sentences. Memorising the entire lecture notes or Periodic Table serve no purpose except to impress Hermione Granger. (!! wait a minute, let me take back the ‘no purpose’ part).
But I really can’t memorise.
There are many techniques available to aid memorization; just do a quick google. Personally, these 2 techniques served me well during my studying days.
(1) Linking new content to something that is already etched in your mind. It takes less effort to extend on an existing knowledge than to create a new and isolated one.
Example: Solubility of Gp II sulfates decreases down the group (new knowledge). From O level Chemistry, you should be able to recall that BaSO4 is a white ppt (prior knowledge). Ba is further down in Group II and BaSO4 is insoluble, therefore solubility of Gp II sulfates must decrease down the group.
(2) Using mnemonics.
Example: The types of reactions that an acid derivative can undergo using the word “GRAHAM”: Grignard, Reduction, Alcoholysis, Hydration, Amminolysis. M is just there to complete the word.
Tip #02 - Practise and internalise the problem-solving sequence.
Every type of problem has a specific sequence of thoughts for it to be solved. Knowing the ‘sequence’ short-circuits the problem-solving process.
| Example: Solving unknown oxidation states of a reactant or product in a redox reaction.
20 cm3 of 0.040 mol dm–3 Fe2+ solution is quantitatively oxidised by 20 cm3 of 0.010 mol dm-3 KMnO4 solution under neutral conditions. Determine the oxidation state of Mn in the product.
Step 1: Identify (1) the reactants involved in the redox reaction and (2) which is the ‘known’ and ‘unknown’ reactant. The known reactant is the one where the species before and after the redox process is known and vice versa. Known: Fe2+; Unknown: KMnO4
Step 2: Find the moles of the known reactant. n(Fe2+) = 20/1000 x 0.040 = 8 x 10–4 mol
Step 3: Find the moles of electron transferred in the reaction. Fe2+ → Fe3+ + e– 1 mol Fe2+ transfers 1 e– n(e–) = n(Fe2+) = 8 x 10–4 mol
Step 4: Find the moles of electron transferred per mol of the unknown (= change in OS of unknown) n(KMnO4) = 20/1000 x 0.010 = 2 x 10–4 mol n(e–) per mol of n(KMnO4) = 8 x 10–4/2 x 10–4 = 4 Change in OS of KMnO4= 4 Since Fe was oxidized; KMnO4 must be reduced i.e. minus 4. Final OS = 7 – 4 = +3
Note: A shorter sequence is available for such problems. |
Got sequence meh? I just do and get the answer.
For people who are competent at solving a particular type of problem, the ‘sequence’ runs at a subconscious/ intuitive level when coming up with the solution. But it is still useful to identify the ‘sequence’ so as to be able to apply it reproducibly i.e. when intuition fails especially under exam stress.
How can I obtain the sequence?
Most of the time, your teachers would have already presented these ‘sequences’ in lectures and/ or tutorials. Make it a point to practise applying the ‘sequence’ when solving questions rather than relying on intuition or ‘feeeeling’ as my students would call it.
Tip #03 - When approaching an unfamiliar question, apply the spotlight approach.
| (1) What chapter/ topic is the qns testing on/ related to? (2) What types of qns are there for this chapter/ topic? Which type of qns is this? (3) What is the problem-solving sequence for this type of qns? |
I look at the question and I don’t even know how to get started.
This is a rather common complaint from students especially in exams where multiple chapters are being tested. In such situations, using the spotlight approach can help you to establish focus and block out interfering content.
Also, students can get confused between topics and apply concepts for one topic incorrectly to another. Using the spotlight approach can help you clarify the correct concepts/ ‘sequence’ to be used.
| Example: A solution containing NaOH is added dropwise to a solution containing Mg(NO3)2. At the instant when a precipitate forms, the concentration of OH– is 1 x 10–3 mol dm–3. Determine the concentration of Mg2+ at this point. Ksp of Mg(OH)2 is 5.60 x 10–12 mol3dm–9.
(1) Chapter/ Topic: Ionic Equilibria/ Solubility Equilibria
(2) Type of Qn: There are two main types of qns for Solubility Equilibria: ‘dissolving’ and ‘precipitation’. The qns above is a ‘precipitation’ type qns.
(3) Sequence: Identify sparingly soluble salt (look for Ksp) → Write ionic pdt for salt → equate to Ksp and solve for unknown.
For students with a weak understanding of the topic, they would do the following upon seeing that the qns involves finding the concentration of Mg2+ .
Let the conc. of Mg2+ be x; conc. of OH must be 2x. Equate to Ksp and find x.
The above approach applies for ‘dissolving’ type qns and the mistake could have been circumvented if the student had applied the Spotlight approach at the start. |
Tip #04 - Fail-proof the crucial 20%.
The Pareto Principle (or 80/20 rule) describes a 80/20 distribution that is found in many aspects of life e.g.
20% of the population own 80% of the riches;
20% of your friends are responsible for sending 80% of smses in your phone;
20% of your clothes get worn 80% of the time.
This concept is also relevant in the context of ‘A’ Level Chemistry in the sense that:
20% of the concepts in each chapter gets tested 80% of the time.
If you are getting ready to pop the champagne thinking that you only need to study 20% of the content, please hold for a second. The rule does not mean that you only need to study 20% of the content, but rather, you need to study 20% like reaaally well.
Anyway, if you are sitting for your ‘A’ levels, chances are you have not met the legal age for drinking so put that champagne away!
How do I know what is the crucial 20%?
By scanning through your tutorial, test and exam questions, you would be able to identify certain recurring concepts and/ or equations.
Make sure that you are 100% clear of these concepts and how to use these equations correctly.
Tip #05 - Pull out in a separate sheet the common mistakes and misconceptions.
As a student, I would write down my common mistakes and misconceptions in a separate sheet of paper and review it from time to time. This gives me a heightened awareness of my potential pitfalls and helps me to sidestep them during exams.Writing it down in the mesh of your notes and there is a high chance that you will miss it during revision.
How do I know my common mistakes and misconceptions?
They can be found in the wrong answers in your tutorials, tests and exams. Next time when you are doing corrections, instead of simply writing down the correct answer, make an effort to examine if you are prone to making a particular error or misconception.
The common mistakes and misconceptions are usually highlighted in lectures, tutorials and exam reviews so do pay special attention to them.
Tip #06 - Constantly review your study approach.
After every major test/ exam, I would ask my students to reflect on the 3 questions:
(1) How did I prepare for the exam? Be specific.
(2) What went wrong/ what went right?
(3) What am I going to do differently for the next exam?
The purpose of this exercise is for you to be consciously aware of your study methods and their effectiveness, and commit to making continual improvisations.
| Example: (1) I browsed through the notes; attempted to memorise the key concepts but not thorough. I tried all the questions in the revision package, referring to the notes/ answers when I can’t solve the questions.
(2) Did not memorise the key concepts well enough so applied them incorrectly for many questions; Attempting the practice questions without a thorough knowledge of the content was ineffective as I had to refer to the notes/ answers most of the time. I did not pay special attention to the mistakes made during practice and hence made the same mistakes in the exam.
(3) I will study the notes thoroughly to ensure that I have a clear understanding and recollection of the key definitions, equations and concepts. I will review my tutorial and tests and clear up any misconceptions and common mistakes. I will attempt the practice questions without referring to the notes. In the event where I can’t solve a question, I will look at the answer, make sense of it, and try the question again. |
- Writing Free Radical Substitution Mechanism
← Back to Alkanes When writing mechanisms: It is a good practice to write the name of the mechanism whether or not the question asks for it. You just need to show the series of equations/ arrows. There is no need for descriptions i.e. the...
- Elucidation
← Back to Organic Chemistry Problem-Solving Approach Approach: Make as many deductions as possible from the information given in the question. Start identifying from the unknown with the most information/ deductions. Make sure all reactions/...
- Ionic Equilibria (acid/ Base)
There are two broad aspects of this chapter: Acid/ Base Equilibria Solubility Equilibria Acid/ Base Equilibria Important Relations p = -log10 At 25°C: pH + pOH = pKw = 14 pKa + pKb = 14 [H+][OH–] = 10-14 Ka x Kb = Kw = 10-14 Approach:...
- Practice Questions (a Levels) - Ocr
GCE AS/A Chemistry [Oxford Cambridge and RSA Examinations (OCR)] You need Adobe Reader to read the files. Click here to download if you do not have it installed in your computer. June 2007 Mole Concept, Atomic Structure & Chemical BondingQuestion...
- Ideal Gas Calculations
Strategies:1. Read the question carefully to extract all the given information: - initial and final T, P, V - no. of moles of gas, n - unchanged conditions (constant T, P, V, n?)For difficult or wordy questions, drawing a simple diagram will aid...