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.

2020 P1 Q27 - Hydrogen Oxygen Fuel Cell in Alkaline Medium

Let Chemistry Guru, Singapore's top choice for JC Chemistry tuition, guide you through 2020 A Levels H2 Chemistry Paper 1 Question 27.

2020 p1 q27 question

We are given a hydrogen-oxygen fuel cell with NaOH as electrolyte.

We need to determine the direction of electron flow in the external circuit and the E value for the oxygen electrode.

Let us first deduce the anode and cathode from the redox reaction between hydrogen and oxygen.

2020 p1 q27 deduce anode cathode for fuel cell

Hydrogen is oxidised to water so electrode X at the hydrogen side is the anode (negatively charged).

Oxygen is reduced to water so electrode Y at the oxygen side is the cathode (positively charged).

So in the external circuit, electron will flow from the negative electrode X to positive electrode Y.

2020 p1 q27 determine electron flow

Next let us determine the correct half equation and E value for the oxygen electrode.

Since oyxgen is reduced, it should be found on the left hand side of the half equation found in the data booklet.

The electrolyte is NaOH(aq), so the reaction is in alkaline medium.

Hence we want the half equation where O₂ is reduced to a product with stable oxidation state, in the presence of OH^-.

2020 p1 q27 deduce E of oxygen electrode in alkaline medium

Comparing the options, the following half equation is the best choice since OH^- is present and oxidation state of oxygen in product OH^- is -2 and stable.

O₂ + 2H₂O + 4e ↔ 4OH^- +0.40V

Finally we can compare the options and determine the answer to this question is option A.

2020 p1 q27 answer