Common Mistakes in Chemistry Part One

Finally, the reason why I started this Blog. Henceforth I will be posting snippets of useful information from the tiny little notebook I carry around that is packed with information. Remember when Mr. Glenn Wong used a lesson to talk about common mistakes made in Chemistry? I copied almost everything down even though none of the mistakes were mine. The same goes with many other subjects, and from time to time I will post information I feel you guys will find useful. Use it well, and get your A's =)

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Chemistry

- "Unsaturated" refers to "An Organic molecule with C=C bonds"
Note: Beware of using the term double C-C bonds because this could mean just mean a C-C bond here and another C-C bond there. The above mentioned definition is the safest.

- SPELL OUT chemicals unless asked for formulas

- When asked for Partial Structures in Organic Chemistry, don't forget to add the brackets and the 'n' symbol.

- There will be NO WRITING OF STATE SYMBOLS BELOW FORMULAS. Instead, write them beside the chemicals otherwise they will be disregarded (according to Mr Wong this is the latest change from MOE or someone higher up so don't complain)

- Ionic and Half Equations REQUIRE state symbols

- The term "precipitate" only refers to reactions between two MIXTURES. Whereas "residue" is used in filtration.

- Mole Calculations require 3 Significant Figures. HOWEVER, during your working, you may come across big values. If they have to be used later, keep them up to about 3 Decimal Places to be safe.

- Final answers during calculations involving Enthalpy Change should be kept exactly. One way to check the answer is that if you know the reaction is Endothermic/Exothermic, you will know the answer should be positive or negative respectively. COMBUSTION is EXOTHERMIC.

That's all for now. If you liked this post, don't bug me when I'm copying stuff down in class, and I'll happily share my notes.