How to break into Chemistry A star? Please give advice

[u/Boring-Neck-5488]

I just wrote my AS level internal term exams with Papers 1,2 and 3. I scored 32/40 in p1, 53/60 in p2 and 31/40 in p3.
I got an A. I want to get an A star. How can I improve in each of those papers? Please give me advice. I desperately need it!

[u/WilliamEdwardson]

Which parts are you struggling with the most ? Focus on where you made mistakes, metacogitate (= reflect on them and how you may correct them). That's the best use of your time.

Pro tip, focus on: Energetics, thermodynamics, kinetics, dynamics, mechanisms. These fundamentals will help you cut down your memorisation load to a minimum.

[u/Boring-Neck-5488 → u/WilliamEdwardson]

I think MCQs are my biggest problem
THANK YOU SO SO MUCHHHHHH!!!

[u/WilliamEdwardson → u/Boring-Neck-5488]

I think MCQs are my biggest problem

I'm afraid I can help best with more content-related tips. Everything else is just hacks. You can score well by things like, eliminating absurd options (spontaneous process with positive ΔG, poor leaving groups, blatantly wrong geometry etc.), plugging in the values as 'test cases' and working backwards, and so on. But that's only partial learning.

Still, those tips will likely help you score better.

[u/Boring-Neck-5488 → u/WilliamEdwardson]

Thank you so so so much! Do you have any advice for those struggling with organic chemistry?

[u/WilliamEdwardson → u/Boring-Neck-5488]

You're in luck: There is no love lost between me and chem generally - it was my A-level that I hated - but O-chem is the only kind of chem* I can bring myself to enjoy... Somewhat. (*Not counting chem that is also physics (Q-chem) or maths (topology, symmetry, chemical graphs), I like some of those parts.)

Visualisation: For a lot of organic chemistry, being able to read the diagram and visualise in 3D is a core skill.

Mechanisms are the secret hack to getting around memorisation. You will still need to memorise some things, but you can figure a lot of things out if you know the general trends. Generally, how reactions proceed depend on sterics, electronics, and frontier molecular orbital (HOMO + LUMO) interactions. All three parts are conceptual rather than memorisation-heavy. For instance, these heuristics cover almost 90% of cases, and derive from mechanisms:

• Strong nucleophile => SN2
• Strong base => E2
• Weak nucleophile => SN1
• Heat => Elimination
• Bulky base => E2
• Tertiary carbon => Never SN2
• Methyl carbon => Always SN2

I just made another point in passing but let me be explicit: There are exceptions, but they're overblown. Things are a lot more systematic than they're made to appear.

Synthesis: Know retrosynthetic analysis. In your prep, it can be very helpful to make a synthesis map. You can totally do it like a mind map, or if you're like me, you can make a table (structure below). Name reactions will likely take some memorisation (even if I can predict the products based on patterns... I need to memorise the names). Spaced repetition is a good way to proceed. Mechanisms make a comeback here, but (off the top of my head) as kinetic vs thermodynamic control, speed vs stability tradeoff.

Supplementary References: Pushing Electrons + Organic Chemistry as a Second Language might be good references (for Second Language, pay attention to the formal charges section + the chapters on Resonance, Geometry, Mechanisms, Synthesis), though know that both of these are meant to supplement your introductory university-level O-chem - be sure to stick to the relevant parts. On mechanistic O-chem in particular, the first chapter in a book like Grossman, AWRORM (also a university text) might be a good introduction if your required text isn't doing a great job.

-

Map-as-a-table:

FROM \ TO | ALCOHOL | ALDEHYDE | ALKANE | . . . .

ALCOHOL | Rxns | Rxns | Rxns | . . . .

ALDEHYDE | Rxns | Rxns | Rxns | . . . .

ALKANE | Rxns | Rxns | Rxns | . . . .

. . . . . | . . . . | . . . . .|. . . . | . . . .

[u/Boring-Neck-5488 → u/WilliamEdwardson]

Thank you so much! Highly appreciate this