Chemguide: Support for CIE A level Chemistry
Learning outcome 14: Hydrocarbons
This statement talks about the relatively small number of reactions which alkanes undergo, and the reasons for this.
Before you go on, you should find and read the statement in your copy of the syllabus.
CIE often try to test your knowledge of organic chemistry by asking searching questions, which sometimes bring in bits from the rest of the syllabus as well.
To my mind, they often make their questions so unnecessarily complicated that the success rate on such a question is ridiculously low. That doesn't matter particularly, because they adjust grade boundaries to make up for this - you will get a particular grade with a lower score than you would with an Exam Board who set easier questions. But it can be very upsetting for candidates at the time.
You have to learn how to cope with this. For this statement (and frequently in the organic section) I am going to ask you to look at material which isn't mentioned specifically in the syllabus at that point. That will give you confidence in answering most questions of this kind.
For this statement 14.1.5, for example, I am going to ask you to read quite a long introductory page about the alkanes, which includes things like their physical properties.
You could argue that this isn't on the syllabus - but it is! As a part of a question about alkanes, they could very well ask you to discuss some feature of their physical properties, because you should know how to do that from the structure and bonding work you will already have done.
If you came across this for the first time in an exam, you probably wouldn't be able to answer a question about it, unless you had already thought about it previously. Coming across something in an exam for the first time can be seriously scary!
You will find all you need to know on the page introducing alkanes and cycloalkanes.
Read the whole of this page, including the bits about cycloalkanes. I know that cycloalkanes aren't mentioned anywhere in the syllabus, but neither are they specifically excluded. It is important that you should at least have heard of them.
If you have forgotten about things like electronegativity or van der Waals forces and so on, don't forget to follow those links to remind yourself about them.
And don't try to rush this! The big mistake too many students (and teachers!) make is to spend too little time on the early stages of organic chemistry. The more time you spend at these early stages, the easier you will find the rest of the organic. If you rush these first bits, organic chemistry will just become a nightmare to you. I keep on stressing this because it is so important.
And never forget: The more you understand, the less you have to learn.
© Jim Clark 2020