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.

Mole Concept Worked Example - Determining Alcohol J

In this video created by Chemistry Guru, Singapore's leading JC Chemistry tuition centre, we have an interesting mole concept question where the molecular formula for alcohol J is unknown and given as C_xH_yOH and we are required to solve for x and y, given data from reaction of J with sodium metal and combustion analysis.

mole concept worked example alcohol J question

Let's first break this question down into diagram form:

mole concept worked example alcohol J question breakdown

The first reaction with sodium will give H₂ gas. So from the volume of H₂ evolved we can determine the number of moles of alcohol J.

The second combustion reaction of the same volume (and hence same amount) of J with oxygen causes a decrease in volume by 54.4cm³, and a further reduction of 109cm³ when NaOH is added.

The reduction of volume with NaOH is due to acidic CO₂ that is absorbed, so we already know that volume of CO₂ is 109cm³.

1. Reaction with sodium

We need to write down the balanced equation between alcohol J and sodium to form salt and hydrogen gas.

We can then determine the amount of H₂ produced and compare mole ratio to find amount of J.

mole concept worked example alcohol J reaction with sodium

2. Combustion Analysis

We need to balance the equation involving combustion of alcohol J (C_xH_yOH) to form CO₂ and H₂O, which is a bit tedious and different from normal combustion analysis questions involving hydrocarbons (C_xH_y).

Since we already know the volume of CO₂ produced is 109cm³, we can work out the volume of oxygen reacted from change in volume.

We can then convert the volumes of CO₂ and O₂ reacted to number of moles.

mole concept worked example alcohol J combustion analysis

Take note for this question we cannot compare volume ratio as alcohol J is a liquid and comparing volume ratio only works on gases (Avogadro's Law).

3. Comparing Mole Ratio

We can now combine information from both experiments and write out 2 mole ratios for the balanced equation in terms of:
a. coefficients x and y
b. number of moles determined from both experiments

mole concept worked example alcohol J compare mole ratio