Final answer:
If 12 molecules of a six carbon molecule with a double bond are joined covalently, the result would be a polymer. The specific structure of the polymer depends on the monomers' structure, with single covalent bonds and potential double bonds forming between carbon atoms.
Step-by-step explanation:
If 12 molecules of a six carbon molecule with a double bond on the third and fourth carbon from the left are covalently joined together in sequence, the single molecule that would result would be a polymer. In the context of organic chemistry, this process is known as polymerization, where similar or identical molecules called monomers are bonded together to form a macromolecule with repetitive structural units.
The molecules in question are suggested to be organic due to the mention of carbon and hydrogen atoms. An example of such a process is the creation of polyethylene, where ethylene (C2H4) monomers join to form a long chain. However, without additional information about the specific structure of the initial molecule, it is not possible to specify which exact polymer would be formed.
When two atoms form a single covalent bond, they share one pair of electrons, as in the case of hydrogen gas (H-H). If the molecule in question has a double bond between the third and fourth carbon atoms, joining 12 of these molecules would result in complex covalent bonding, contributing to the structure of the polymer.
It is important to note that the process of forming polymers often requires conditions such as heat, pressure, and the presence of a catalyst.