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 Q15 - Determine Suitable Indicator for Equivalence Point

Let Chemistry Guru, Singapore's prestigious JC Chemistry tuition centre, guide you through 2020 A Levels H2 Chemistry Paper 1 Question 15.

2020 p1 q15 question

We need to determine which indicators can be used to show the first and second equivalence points for the titration of triprotic acid H₃PO₄ with NaOH.

The working range of the indicator is its pH range of colour changes.

This info is given in the question.

The equivalence point is the midpoint of the region of rapid pH change for the titration curve.

From the titration curve in the question, we can determine that:

1. First equivalence point is at 50.0cm³, range of rapid pH change is around pH 3 to 6
2. Second equivalence point is at 100.0cm³, range of rapid pH change is around pH 8 to 11

An indicator is suitable when its working range lies within the range of rapid pH change for the titration curve.

We can highlight the working ranges for all the indicators in the titration curve to see which ones are suitable.

2020 p1 q15 compare range of rapid pH change and working range

Naphthyl red is suitable to show the first equivalence point, since its working range of pH 3.7 to 5.0 is within range of rapid pH change of pH 3 to 6 for first equivalence.

Thymol blue is suitable to show the second equivalence point, since its second working range of pH 8.0 to 9.6 is within range of rapid pH change of pH 8 to 11 for second equivalence.

We can now look at the options and determine that option B is the answer to this question.

2020 p1 q15 answer