# [J1] Lesson 43 (COE Headstart L2+ (Headstart) Probability L1+ (Headstart) Acid Base Equilibrium L2)

[J1 Physics PMCians] Headstart : Current of Electricity & DC Circuits (Part 2)

What we did in 2 hours:

This week, we continued where we left off on DC Circuits.
We reviewed the fastest way to calculate the potential difference, V, across any resistor in a series circuit using the Potential Divider method. We also shared the special Current Divider method for parallel resistors.

Special Mention:

We will continue with our final part 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:

Carrying on with Permutations and Combinations, we picked up our last technique, dealing with permutations in a circle. We noted the difference between ordered and un-ordered circles, in particular the case where we have groups in an ordered circle: remember approach it as
• 1. unordered first, then
• 2. times the number of seats!
Additionally, these were applied to a full suite of questions. P&C is a topic with massive breadth, it is important to build up experience and always consider changing the approach – remember how number of colours was more important than number of balls?

What you take home:

Worked solutions for the remaining questions in P&C as well as the daily dose solutions have been uploaded here.

Special Mention:

We will complete the rest of probability this week.
See You and Stay Healthy!
Your Friendly Math Tutors

[J1 Chemistry PMCians]

What we did in 2 hours:

In this lesson, we revised the key ideas from the previous week on Acid Base Equilibrium, discussing the misconceptions arising due to strength of acids and bases as well as their concentrations. We reviewed also the key concepts when water ionises (slightly) on its own.
The main focus of the lesson discusses the calculation of pH values for strong & weak acids and bases. We also understood that salts are not always neutral – there are acidic and basic salts. We learnt how to recognise them and understood how they create an acidic or basic solution.

Special Mention:

Next lesson, we will look at an interesting type of solution – the buffer solution.
Gentle reminder – if you wish to discuss your promo papers, do remember to scan and send it to me via PMC whatsapp.
See you in class!
Mr Leong