In addition to alkanes, cracking reactions may also involve alkenes, alkynes and aromatics. For each of the following reactions, draw a structural formula equation. Include all reactants and products:

We can't draw structures on this forum. You can google each of the names and most sites, especially Wikipedia, will give you a structure.

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Sure! I'd be happy to help you understand how to draw the structural formula equations for these cracking reactions.

a) but-1-ene --> ethyne + ethane
To draw the structural formula equation for this reaction, we need to represent the reactant and product molecules using their structural formulas.

Reactant: but-1-ene
The structural formula for but-1-ene is:

H H H H
| | | |
H-C-C-C-C-H
| | | |
H H H H

Product 1: ethyne
The structural formula for ethyne (also known as acetylene) is:

H H
| |
H-C≡C-H
| |
H H

Product 2: ethane
The structural formula for ethane is:

H H
| |
H-C-C-H
| |
H H

So, the structural formula equation for the reaction is:
but-1-ene --> ethyne + ethane

b) 3-methylheptane --> but-2-ene + butane
For this reaction, we need to draw the structural formulas for 3-methylheptane, but-2-ene, and butane.

Reactant: 3-methylheptane
The structural formula for 3-methylheptane is a bit complex, but I'll try to represent it using text:

CH3 CH3 CH3
| | |
H3C-C-C-C-C-C-C-C-H
| | |
CH3 CH3 CH3

Product 1: but-2-ene
The structural formula for but-2-ene is:

H H H H
| | | |
H-C-C-C=C-H
| | | |
H H H H

Product 2: butane
The structural formula for butane is:

H H H H
| | | |
H-C-C-C-C-H
| | | |
H H H H

So, the structural formula equation for the reaction is:
3-methylheptane --> but-2-ene + butane

c) 3-methylheptane --> propene + 2-methylbut-1-ene + hydrogen
To draw the structural formula equation for this reaction, we need to represent the reactant and product molecules.

Reactant: 3-methylheptane (same as mentioned in part b)

Product 1: propene
The structural formula for propene is:

H H H
| | |
H-C-C-C
| | |
H H H

Product 2: 2-methylbut-1-ene
The structural formula for 2-methylbut-1-ene is:

H H H H H
| | | | |
H3C-C-C-C-C-C-H
| | | | |
H H H H H

Product 3: hydrogen
Hydrogen (H2) is simply represented as H.

So, the structural formula equation for the reaction is:
3-methylheptane --> propene + 2-methylbut-1-ene + hydrogen

d) propylbenzene --> benzene + propene
For this reaction, we need to draw the structural formulas for propylbenzene, benzene, and propene.

Reactant: propylbenzene
The structural formula for propylbenzene is:

H H H H
| | | |
H-C-C-C-C-C-C6H5
| | | |
H H H H

Product 1: benzene
The structural formula for benzene is a ring with alternating double bonds:

H
|
H-C=C-C=C-C=C-H
|
H

Product 2: propene (same as mentioned in part c)

So, the structural formula equation for the reaction is:
propylbenzene --> benzene + propene