So, three words representing three different groups of organic compounds. Alkanes for all single bonds, alkenes if they contain double bonds, and alkynes if they contain one or more triple bonds.
The fatty acid chains, they have long hydrocarbon chains, are what we're mostly concerned with here. They can be alkanes or alkenes, sometimes even rarely alkynes.
You also learned a little bit about cis-trans isomerism and learned a few important reactions of alkenes and alkynes such as hydrogenation, halogenation, and polymerization.
All the other naming rules apply to alkenes and alkynes too. For instance, the main carbon chain, the longest one, is numbered in such a way that the various components, including the double bond, have the lowest numbers possible.
Now, the bonds in alkenes have a few tricks up their sleeves, not as simple as you might imagine. Single bonds, also called sigma bonds, are pretty simple, and carbon atoms attached by them can rotate around the bond freely.
How do you remember which is which? Well, I have a trick that I use. There's only one letter changing here. A in alkanes changes to E for alkenes and then to Y for alkynes.
如何记住它们各自代表什么?我有个小技巧。这里只有一个字母在变化:烷(alkanes)中 A 变为烯(alkenes)中 E,再变为(alkynes)中 Y。
Just to note to avoid confusion: polyethylene has that " -ene" sound in it, right, but it's not an alkene because all those double bonds get broken to form new sigma bonds.
That may not sound like a big deal at first, but alkenes and alkynes don't have that kind of freedom, and that simple fact has a huge affect on their properties.
That may not sound like a big deal at first, but alkenes and alkynes don't have that kind of freedom, and that simple fact has a huge effect on their properties.
If you paid attention, you learned that hydrocarbons with double bonds are called alkenes and those with triple bonds are called alkynes and that the naming rules are the same as for alkanes.
Then, a little chemistry knocked the acid off, creating what was clearly an alkene, so they named it benzene, because it was an alkene that was from the benzoin resin.
So three words representing three different groups of organic compounds: alkanes for all single bonds, alkenes if they contain double bonds, and alkynes if they contain one or more triple bonds.