nomenclature hydrocarbons (chapter 17)

• Scheikunde
• Middelbare school
• havo
• Leerjaar 3

Chapter 17: hydrocarbons

Learning goals

• What are hydrocarbons?
• You can draw the structural formula of hydrocarbons
• You know isomers

Crude oil

• Consists of more than 100.000 substances
• Most of them are hydrocarbons

Hydrocarbons

A substance that consists of only C and H atoms

There are different subgroups, for example the alkanes.

Alkanes

General formule

• Alkane C_nH_2n+2

L

Wat is de molecular formula of octane?

Wat is the name of

C​4​​H​10​​

1. Methane
2. Ethane
3. Propane
4. Butane

What is the name of the
structural formula:

1. heptane
2. hexane
3. nonane
4. octane

Alkenes can be branched. Branched groups with only C and H atoms are called alkylgroups. Methyl for 1 x C, Ethyl for 2 x C etc. 

Isomers

• molecules with same molecular formula, but different structure
  
• Due to structure also different properties

C₄H₁₀                      C₄H₁₀

Butane            methyl-propane

Why is this the same molecule?

and not a isomer?

Draw two isomers of C5H12

Nomenclature

Step by step plan

1. Longest C- Chain (unbranched)

2. Sidechain: Methyl (-CH3) or ethyl (-C2H5) etc.

3. Number: Number longest C chain and tell which place the side chain have (as low as possible)

C₄H₁₀                      C₄H₁₀

Butaan            methyl-propaan

But what is the side chain is there more than once? 

Use 

di (2), 

tri (3), 

tetra (4), 

penta (5)  

 hexa (6). 

Also in the numbers

2,2,4-trimethylpentane

C₄H₁₀                      C₄H₁₀

Butaan            methyl-propaan

What if you have more side chains

For example 1 methyl- and 1-ethyl

Alfabetic!

3-ethyl-2-methylpentane

C₄H₁₀                      C₄H₁₀

Butaan            methyl-propaan

What is the systematic name of:

1. 2-methyl-3-ethylhexane
2. 3-ethyl-2-methylhexane
3. 5-methyl-4-ethylhexane
4. 4-ethyl-5-methylhexane

Wat is de systematische naam van

1. 2-methyl-3-ethylpentane
2. 3-ethyl-2-methylpentane
3. 4-methyl-3-ethylpentane
4. 3-ethyl-4-methylpentane

Now yourselves

Worksheet

Leerdoelen

• Wat zijn koolwaterstoffen?
• Je kan een structuurformule van alkanen tekenen
• Je kent isomeren

Teken de structuurformule van 3,4-dimethylnonaan