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.

Determine Moles of Electrons Gained per Mole of Oxidising Agent

240110 question

Let's put down all the information we have from the question so far.

240110 info

96 dm³ of NO₂ is oxidised to NO₃^- while 2 moles of XO₄^- is reduced.

These are the recommended 4 steps to determine oxidation state of unknown species from experimental data:

240110 4 steps

1. Determine moles of reactants

At room temperature and pressure, moles of NO₂ = 96 / 24 = 4
Moles of XO₄^- = 2 (given)

2. Determine moles of electrons transferred in reaction

We need to balance the oxidation half equation of NO₂ in acidic medium.

240110 oxidation half equation of NO2

From half equation, mole ratio of electron lost to NO₂ is 1 to 1.

240110 mole ratio e to no2

Hence mol of electron lost by NO₂ = mol of NO₂ = 4 = mol of electron gained by XO₄^-

This step is fundamental since we know redox reaction is a total transfer of electrons from reducing agent to oxidising agent, so moles of electrons involved in oxidation of NO₂ and reduction of XO₄^- will be the same.

3. Determine mole ratio of electrons to XO₄^-

240110 mole ratio e to xo4

This basically says that each XO₄^- gains 2 electrons, so the answer to this question will be B.

240110 answer

The question didn't require us to find final oxidation state of X, but we can easily do that since we know the initial oxidation state of X and change in oxidation state.

240110 reduction half equation of xo4