# [J1] Lesson 42 (COE Headstart L1+ (Headstart) Permutations & Combinations L2+ (Headstart) Acid Base Equilibrium L1)

[J1 Physics PMCians] Current of Electricity & DC Circuits

What we did in 2 hours:

Welcome back from your Promo exams. We know you have done your best, and we rejoice with all of you for the good effort for your exams.

This week, we began our Headstart program with DC Circuits.

In our first lesson, we delved into Resistance, and how to calculate the effective resistance of a given circuit. We are sure you noticed that the circuits are now more complicated than in the O-levels. 🙂

Special Mention:

We will continue part 2 of DC Circuits next week.

Till then, stay healthy and positive!

Cheering you on!!
Mr Sim & Mr Kwok 🙂

[J1 Maths PMCians]

What we did in 2 hours:

Welcome back! Congrats for making it through the promos! 🙂

We resumed our lessons with a quick introduction to Statistics, through the Permutations & Combinations chapter.

Recall the basic techniques you picked up

– line permutations (and if there are repeated objects?)

– combinations (ordered or not?)

as well as further techniques to deal with certain situations, grouping, slotting and using complements being particularly useful. Also, when generating cases to break up a problem, do always be wary of overlapping cases!

Special Mention:

We will carry on with P&C this week and move on to Probability too.

See You!

[J1 Chemistry PMCians]

What we did in 2 hours:

A big welcome back to PMC!

We began to look at a typically harder JC2 chapter on Acid Base Equilibria, which deals with equilibrium arising from weak acids and bases. We spent quite a bit of time clarifying some of the misconceptions that were brought forward from our secondary school days – Does a high pH necessarily mean a weak acid? Does a weak base need less acid for neutralisation than a strong acid? Can pH values range beyond 1 – 14?

Special Mention:

Next lesson, we will look at how we can calculate pH of strong and weak acids/bases.

Cheers!

Mr Leong