March 2010 | SimpleChemConcepts

Monthly Archives: March 2010

Mole Calculations Mastery Workshop 2010 – Successful Completion

Written on March 19, 2010 by sean in Announcement, Chemistry Coaching

With 1-week March School Holidays in Singapore coming to an end, we have also successfully conducted our 3 Days annual Mole Calculations Mastery Workshop 2010 during this holiday period.

Mole Calculations Mastery Workshop 2010 Class Pix

The 3 days was fun-filled with plenty of activities, participation and discussions. I am very proud to say that this current group of students that had just completed the said workshop is one of the best batch i have ever coached. They didn’t know much about Mole Calculations (some call it Mole Concepts) when we first started, but their enthusiasm and willingness to learn makes it a joy to coach them. They were so responsive and highly motivated to do well for this voted No. 1 Killer Topic in GCE ‘O’ Levels (and IP and IGCSE) Chemistry. Students were from the following secondary schools:

Cedar Girls’ Secondary School
Clementi Town Secondary School
Dunman Secondary School
Junyuan Secondary School
Outram Park Secondary School
Raffles Girl’s School
St. Andrew’s Secondary School
St. Hilda’s Secondary School
St. Margaret’s Secondary School
Tanjong Katong Girl’s School
Whitley Secondary School

It is wonderful to know that we have coached students from more than 80 Secondary Schools in Singapore as well as a couple of them from overseas ie, malaysia, indonesia, mauritius, etc – making a difference to their lives through our coaching.

Mole Calculations Pix 1

It is always great to know that the participants felt good excellent motivated & confident after the completion of each workshop. Here is a few thoughts on recent Mole Calculations Mastery Workshop:

“Personally I feel this workshop has helped me a lot as before I started if I was lost in the chapter of Mole Calculations. But now after attending this workshop, it has gave me a lot of confidence to face Mole questions. I would be happy to recommend this programme to my fellow friends as I think it would help them out too!”

Jedaiah Gwee, St. Andrew’s Secondary School

“Through this programme, I have literally had tremendous improvement for Mole Calculations =) In the past, I really couldn’t get a single questions on

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O Level Chemistry: Mole Calculations – Concentrations of Solutions

Written on March 9, 2010 by sean in Chemistry Notes & Tips

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In Mole Calculations, many students lose marks in questions related to Volumetric Analysis, especially on those that requires them to understand the concepts of CONCENTRATIONS of solutions. Volumetric Analysis are always a highlight in our annual Mole Calculations Mastery Workshop.

Concentrations of a solution refers to the amount of solute dissolved in 1 dm3 of the solution.

Do note that:

Solution = Solute (minor component) + Solvent (major component)

Usually in basic chemistry such as O Levels, the solvent used is Water. As such, the solution formed is usually aqueous solutions whereby certain solid or liquid are dissolved in water.

Concentrations can be expressed in:

Grams of solute per dm3 (unit will be g/dm3)
Moles of solute per dm3 (unit will be mol/dm3)

The most important formulae student need to know in volumetric analysis are:

Conc. (mol/dm3) = Amt. of Solute (mol) / Vol. of Solution (dm3)

Conc. (g/dm3) = Amt. of Solute (g) / Vol. of Solution (dm3)

Let’s check out a question to see how we can use the formulae above.

Question:

60g of NaOH is dissolved in water and make up to the total volume of 500cm3. Calculate the

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O Level Chemistry: Mole Calculations – Balanced Chemical & Ionic Equations

Written on March 8, 2010 by sean in Chemistry Notes & Tips

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As you can see from the on-going survey on the right hand side, Mole Calculations (commonly known as Mole Concepts) has been voted by students as the #1 Killer Topic in O Level Chemistry (and other equivalent basic Chemistry Syllabus).

In fact, a large number of students skip the calculation-based questions when they see it on Chemistry examination, fearing that they spend alot of time on that question, and yet could not answer it.

Over the years, this topic is often voted the “Hot Favorite” on students’ challenging topics. Some:

have problems understanding what the question is asking for
do not know where to start
totally blank when they read the question
too confused with the formulae to use
gave up on Mole Calculations totally

Many a times, question will require you to write a Balance Chemical Equation in order to solve the question. Other times, they will also require you to write the Ionic Equation and state the Spectator Ion.
As such you will need the following basic foundations that i have shared some time ago:

4 Steps-Process to write a Balanced Chemical Equation

7 Steps-Strategy to write the Ionic Equation & Spectator Ion

The best way to learn is NOT TO READ, but to DO IT!

Let’s try out one exam-based question(similar to O Level Chemistry Exams):

Question 1:

Copper (II) oxide reacts with dilute sulfuric acid to produce a salt, copper (II) sulfate and water. This process is known as Neutralisation.
i) Write a balanced chemical equation with state symbols
ii) Write the ionic equation and state the spectator ion of this reaction

PS: Try it out and leave your answers below.

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