How to Memorise Reagents and Conditions in Organic Chemistry?

Memorising organic chemistry reactions is arguably the most important and fundamental aspect of mastering organic chemistry.

It is also the toughest as there are so many reagents and conditions to remember, and many of them are very specific and technical.

Students are often intimidated by the sheer volume of work and delay memorising the reagents and conditions, usually resulting in them getting a weak grasp of organic chemistry.

But memorising reagents and conditions for organic chemistry is akin to memorising the multiplication table for mathematics – you just can’t do any organic chemistry questions without knowing the reactions.

Chemistry Guru, Singapore's reputable JC Chemistry tuition centre, shares four tried and tested methods that you can use to finally commit these reactions to memory.

1. Verbal Recall

Let’s say you have the following reaction involving nitration of benzene to memorise.

To memorise the reagents and conditions, don’t just look at it and think about it.

Our brain works so fast that sometimes we think we know the content, but are unable to put it into words or write it down in exams.

Do this instead - take a good look at the reagents and conditions and say the content out loud.

Verbalising the things you want to memorise will help internalise the concept as the info has to be transmitted from your eyes to your brain for processing, then that processed info is transmitted to your lips and vocal cords for you to say the concept out loud.

Notice this in itself is already a repeated reinforcement which works wonders in remembering things.

Then cover the reagents and conditions that you are supposed to memorise with your hand or small item so that you cannot see it.

Say the covered content out loud again, and check if you have gotten it correct.

Get the correct answer? That’s great! Not quite there yet? Try again!

Sometimes you might need a few tries to get it correct, but verbal recall is a good way to memorise content.

2. Creating Mnemonics

Maybe you are still trying to memorise the same reaction involving nitration of benzene, but just can’t seem to remember the reagents and conditions no matter how many times you tried the verbal recall method.

Some of the content we need to memorise in organic chem are so technical and specific that they don’t make any sense.

One powerful technique you can use then is creating your own mnemonic.

A mnemonic is a pattern of letters, ideas or associations that help us remember something.

For our example of nitration of benzene, the reagents and conditions are conc HNO₃, conc H₂SO₄, 50 to 60 ^oC.

A mnemonic you can use to remember this is: NASA (as in National Aeronautics and Space Administration in United States responsible for space program and research), Area 51 (as in the classified US Air Force facility that is the frequent subject of conspiracy theories of UFOs and aliens)".

You have to agree that NASA, Area 51 is definitely easier to remember than conc HNO₃, conc H₂SO₄, 50 to 60 ^oC!

Pro tip - invent your own mnemonic instead of using other peoples’ as the active process of creating the mnemonic will help you remember whatever you want to memorise, sometimes even before you finish inventing that mnemonic!

Make your mnemonic funny or just plain ridiculous – you will remember it even better!

Let me give you another example involving electrophilic addition of water to alkene to form alcohol.

The reagents and conditions are H₂O(g), conc H₃PO₄, 350 ^oC, 70 atm.

In this case we can use S to represent steam, and PA to represent phosphoric acid so altogether this will spell SPA.

How about the temperature 350 ^oC and pressure 70 atm? It’s tough to remember a specific number, and you have 2 different sets of numbers to memorise here.

In this case we can convert the numbers to letters:

So 350 becomes CEO and 70 becomes GO.

Remembering words are definitely easier than numbers that don’t make sense.

You can use different systems to convert numbers to letters as long as it works for you.

So H₂O(g), conc H₃PO₄, 350 ^oC, 70 atm now becomes CEO GO SPA.

The mnemonic sequence is rearranged so that the phrase makes sense, eg "after a long tiring day at work, the company CEO GO SPA to relax".

Here’s another way to remember numbers - we can associate the number to things that are familiar to us.

When you look at that number, what does it remind you of?

Maybe 70 is the age of your grandpa and 350 reminds you the cost of a bun at $3.50.

Then we can remember the same reagents and conditions as this phrase "my grandpa buys me a steam bun and Pepsi for breakfast that costs $3.50"

So you see mnemonic creation is very versatile and it’s up to your creativity to come up with ways to remember content that is hard to memorise.

We can also use mnemonics to remember a list.

For instance the names of the first ten alkanes are: methane, ethane, propane, butane, pentane, hexane, heptane, octance, nonane and decane.

Now that’s a whole list of names to memorise, but let’s remember this mnemonic instead: My Excited Polar Bear Plays Hula Hoop On Napping Donkey.

Pro tip - for long lists like this, it will be easier to remember the mnemonic if it is funny and involves action.

Hopefully you can see that mnemonics is a powerful tool that you can use to remember technical terms, numbers, long lists and so on.

All you need is a little bit of time and tons of creativity. Remember to make the mnemonic funny so you can have a good laugh while learning chemistry!

3. Drawing Concept Maps

Once you memorise the reagents and conditions via verbal recall and mnemonics, it’s time to put all these reagents together via concept maps.

Drawing concept maps is a fantastic way to have a one-page overview of all the reactions you need to know for a specific functional group.

You can visualise the relationship between various functional groups so concept maps are really useful summaries of the organic reactions you need to know.

Choosing a suitable organic compound for each functional group can be a bit tricky since you want all the reactions you need to memorise to be represented by that chosen compound.

If you don’t know where to start, you can check out these concept maps that Chemistry Guru, Singapore’s leading JC Chemistry tuition centre, has compiled for all our organic chemistry lessons.

For each concept map, take note of the total number of preparation reactions and reactions that you have to remember.

For example, alkene functional group has 2 preparation reactions and 7 reactions.

For each reaction, use the verbal recall method to test if you can remember the reagents and conditions.

For those that you have difficulty memorising, try to create mnemonics to make it easier to remember.

Once you have a rough grasp of most of the reactions, it's time to draw the concept map from scratch!

You don't need to remember all the reactions perfectly as you will still have plenty of chances to recap them.

Here's what you do:

1. Take out one blank piece of paper and draw the functional group at the centre.

2. Without referring to any notes or guides, write down the reagents and conditions, and the products formed for each reaction. Essentially you are trying to reproduce the concept map from scratch without any reference.

3. Compare what you have written down from memory with the sample concept map with all the correct reactions.

4. See how many reactions you have nailed down correctly.

5. For the reactions that you didn’t manage to recall, use the verbal recall and mnemonic method to review them again.

6. If your existing mnemonic is not working, try creating another one.

7. Once you think you are ready, repeat the process from Step 1.

It’s hard to get all the reactions correct at the first try. Just keep practising and you will make progress.

Remember how you learnt how to walk as a baby (probably not)? Or how you learnt how to swim or ride a bicycle?

You failed and failed but eventually you got it. Because you kept trying and never gave up.

Learning Chemistry is pretty much the same.

4. Diffuse Learning

The last strategy to memorise organic reactions is to simply sleep on it.

No I’m not joking.

During sleep or in a relaxed state, your brain is subconsciously reviewing all the information that you have previously learnt and converting them to long term memory.

This process is called diffuse learning and together with focused learning, is a learning model popularised by American academic and author Barbara Oakley.

During focused learning, you employ the three above-mentioned methods (verbal recall, mnenomics, concept maps) to actively remember as many reactions as possible.

Then you take a break from chemistry and focus on other subjects or activities.

During your rest or sleep, your brain will be engaged in diffuse learning, making connections and building links to your concepts passively even without you consciously thinking about it.

The next day when you come back to revising organic chemistry, you should find it easier to recall the previous reactions, so you can build on that foundation and memorise new reactions.

In order for focused learning and diffuse learning to work, you need to revise frequently instead of taking long breaks of many days between revision.

If the breaks are too long then you will eventually forget about the memorised content since there is no repeated reinforcement.

Initially when you are not familiar with the content, revision should be done once every few days.

Eventually you just need to revise once a week and gradually once a month and will still be able to recall most of the reactions.

Diffuse learning (or sleeping on it) works best when you study in shorter sessions over many days.

So 1 hour of revision everyday for 7 days will yield better results than 7 hours of revision in 1 day.

This is because when you are not actively revising organic chemistry, your brain is still subconsciously engaged in diffuse learning.

It’s almost like a free deal – you are learning without actually being conscious about it!

So it’s always a good idea to start your revision early and take advantage of the wonders of diffuse learning to memorise organic chemistry!

Conclusion

We hope we have given you a good idea on the methods you can employ to finally memorise organic chemistry reactions.

In fact you can apply these same learning techniques to other subjects as well!

At Chemistry Guru, Singapore’s esteemed JC Chemistry tuition centre, we teach important studying techniques, such as the ones mentioned in this article,  to our students so they have the necessary skills to master A Level H2 Chemistry.

Remember to start your revision early and keep trying. Good luck!

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