Over last few years, many students that i spoke to always complaint to me about Mole Calculations. Parents that called up to ask for help in Chemistry for their child always never failed to mention that their child cannot understand and score the “Calculation part of Chemistry“.
Several months ago, we decided to start a poll/survey for readers of this chemistry blogsite to investigate on the biggest challenge that students faces in learning chemistry. Months later, we have more than 100 polls on their biggest challenge, and this exclude those that read this blog, but did not do their polling. There are certainly thousands and millions of students that do not know this chemistry blogsite yet. I certainly would like to know how they feel about it. Do feel free to forward this blogsite for their learning.
If you look at the POLLING on : “Vote your biggest challenge in learning Chemistry” which is located on the Right-hand side column, you will noticed that closed to 50% have chosen Mole Calculations as the toughest topic in Chemistry. This is followed by Qualitative Analysis.
Yesterday, i decided to sit down and collate all the reasons that students have expressed difficulties in learning and scoring for Mole Calculations. And they are (not in order of ranking):
1. Do not know where to start after reading the question
2. Not sure which formula (or combination of formulae) to use
3. Problem in applying the chemistry theories and mathematical formulae together to solve questions
4. Problem in memorizing the formulae because don?t understand how it is being used
5. Problem in getting the correct chemical formulae for each compound
6. Problem in balancing the chemical equation in order to continue other parts of question
7. Cannot see the overall map (steps) in getting final answer
8. Not enough time in answering questions requiring calculations
And for those taking GCE O Level – based examinations, this might not be a so good news for you, especially if you do not do well for Mole Calculations yet. Based on my analysis for past 10 years GCE O Level examinations papers, Mole Calculations is something that you cannot skip at all – in fact, nowadays, the trend is that they don’t appear in one full question. Instead, they are always linked to questions from other topics such as:
* Acids, Bases and Salts (high occurrence)
* Organic Chemistry (high occurrence)
* Combustion Process (high occurrence)
* Rates of Reaction (high occurrence)
* Energy Changes
* Metal & Its Reactivity Series (high occurrence)
* Atmosphere & Environment
* Periodic Table & Group Trends
* Ammonia & Fertilizers (high occurrence)
And because you have to answer almost all the questions in Paper, this simple means there is no way you can leave out Mole Calculations, and want to still score well for Chemistry.
Mole Calculations involves formulae, stoichiometry, mole concepts and chemical calculations.
Besides Paper 1 (MCQs), they are usually tested in exams in Paper 2 (both section A and B) by combining with other topics, as mentioned above.
Hope you find this TIP useful to you. =)
PS: I will post up subsequent blogpost on sub-topics that are related to Mole Calculations.
- O Level Chemistry – Secrets of Acids, Bases & Salts & Qualitative Analysis revealed!
- O Level Chemistry – Mini Series on Tough MCQs Part 3
- Tips for O Level Chemistry Paper 1 (MCQs) Exam
- O Level Chemistry: Mole Concepts / Chemical Calculations
- O Level Chemistry Questions – Mole Calculations / Mole Concepts