What are the different types of JC Chemistry tuition classes available at your centre?

We have 3 modes of learning for students to choose from: weekly physical classes at Bishan; weekly online lessons via Zoom; and on-demand video lessons.

Are you the only Chemistry tutor conducting the classes or do you engage other tutors to do that?

Please be rest assured that I conduct all my classes personally and I do not engage other tutors to teach at my centre.

How well do your students perform after attending your H2 Chemistry tuition classes?

Most of my students showed improvements by at least 3 grades and more than 80% have attained distinction for A Levels. The earlier the students join my classes, the more confident I am in improving their grades.

What is your class size at Bishan?

Usually the class size is around 10 to 12 students. Max class size is 16 pax.

Is there makeup lesson if I miss a class?

Yes makeup lesson is available in the same week subject to availability. If makeup class is not possible, the student can view the recorded video lessons at Google Classroom.

Do you have trial lesson available? How much is it?

Yes we do. Fees for trial lesson are for Bishan class and for Zoom online class.

Does your centre offer O Level chemistry tuition? Do you teach IB / IP chemistry tuition? How about H1 Chemistry?

Chemistry Guru specialises in H2 Chemistry for JC1 and JC2 or IP Year 5 and IP Year 6 students only. Find out all the information about A Level H2 Chemistry and the detailed comparison between H1 and H2 Chemistry. We do not conduct lessons for H1 Chemistry, O Level Chemistry, IB Chemistry or IP Chemistry at IP Year 3 and IP Year 4.

Aldol Addition Reaction

In this video created by Chemistry Guru, Singapore's leading JC Chemistry tuition centre, let's discuss aldol addition reaction of carbonyl compounds.

The name aldol is derived from aldehyde (ald-) and alcohol (-ol), but compounds which contain ketone and alcohol are also considered as aldols.

This reaction is not in A Level Chemistry Syllabus but is quite common in JC Prelim questions so it's a good idea to have an idea what this reaction is about.

aldol addition reaction equation

Using a strong acid or base catalyst, 2 carbonyl compounds can react to form a beta-hydroxy carbonyl compound.

The alcohol functional group is 2 carbons away from the carbonyl functional group.

Let's consider the mechanism of aldol addition reaction, using a base catalyst as an example, to understand this better.

Mechanism (base catalysed)

1. The base can extract a proton from alpha-alkyl carbon to form a negatively charged alpha carbanion.

aldol addition reaction mechanism step 1

2. The carbonanion acts as nucleophile and attack carbonyl carbon.

aldol addition reaction mechanism step 2

Notice this is very similar to the nucleophilic addition reaction that is in A Level Chemistry syllabus.

3. The negative oxygen extracts a proton from water molecule to form the product and regenerates OH^- catalyst

aldol addition reaction mechanism step 3

Predicting Products for Aldol Addition Reaction

With the understanding of the mechanism we can now predict the products that each of these carbonyl compounds can form when they undergo aldol addition reactions.

1. ethanal

aldol addition reaction reactant ethanal