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.

Deduce Propagation Step for Free Radical Substitution of Ethane

Let Chemistry Guru, Singapore's esteemed A Level Chemistry tuition centre, guide you through our discussion question this week!

221031 question

We want to deduce which is a propagation step in the free radical substitution between bromine and ethane.

Check out the following video to learn more about FRS mechanism of alkane.

Let's recap the features of propagation step.

221031 propagation properties

1. The number of reactive radicals stay the same hence the reaction continues or propagates.
2. Only involves breaking 1 bond and forming 1 bond homolytically.

Here are the standard propagation steps for monosubstitution of ethane.

221031 ethane propagation

1. Bromine radical attacks ethane and takes H to form HBr and ethyl radical
2. Ethyl radical attacks bromine molecule and takes Br to form bromoethane and bromine radical

The bromine radical is regenerated to attack another ethane for another monosubstitution, or bromoethane for disubstitution.

Let's run through the options and see which is a possible propagation step.

A. CH₃• + Br₂ → CH₃Br + Br•

221031 option A