To:
Students in Singapore taking GCE ‘O’ Levels Chemistry Exams and using Marshall Cavendish’s Chemistry Matters as Reference Textbook
Besides the error on Electrolysis Topic that we have posted earlier, there is another error spotted in Organic Chemistry. It is shown on page 393 under “Test Yourself 22.1 – Worked Example”.
As we all know, Carbon (C) is found in Group IV of the Periodic Table and has 4 valence electrons. As such, the maximum number of covalent bonds that a carbon atom can formed is 4!
Zoom into Hydrocarbons B and you realised that the 2nd carbon atoms (counting from right side of structure) have:
1 C=C bond
1 C-C bond
2 C-H bond
This gives the 2nd carbon atom 5 covalent bonds which is incorrect. Please note. The correct structure should have only 1 C-H bond, rather than 2. In that way, you can solve the question which test you on Isomerism in Organic Chemistry.
Note:
Looking at the total number of covalent bonds for all the carbon atoms in an organic compound is the step you should take each time when you draw out the structural formula.
Thank you – if you are one of the two students that brought this out for our attention. We appreciate it! =)
PS: Leave us a comment on how you feel about this blogpost and it’s information. We would love to hear from you.
Related Articles:
- More Errors in Marshall Cavendish GCE O-Level Chemistry Matters Textbook – Part 3
- O Level Chemistry: Intro to Organic Chemistry – Part 1
- O Level Chemistry Question: Chemical Bonding & Structural Properties
- O Level Chemistry: Difference between Atom, Molecule & Particle
- O Levels Chemistry Tips Blog Marathon – Day 5
sean says
I believe it should be C6H12O6.
You can do a simple search on Google or Yahoo search engines.
Sean Chua
zara says
sir what is general molecular formula of glucose
sean says
Hi pinacolada,
General Molecular Formula of Carboxylic Acids are CnH2n+1COOH.
Do note that “n” is NOT the “number of carbon atoms” for Carboxylic Acids.
Instead, “n” = number of carbon atoms – 1.
Try it our for the different members of Carboxylic Acids Homologous Series and you will understand what i mean.
Hope this information helps.
PS: Good question – this is one of the common misconceptions by chemistry students!
pinacolada says
i would like to ask about the carboxylic acid.gerneral formula is CnH2n+1COOH correct? or Cn-1H2n-1COOH? becouse most of the textbook are saying CnH2n+1COOH pls advice