<span>The answer is 8. Hope this help!!!
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The substance that can be broken down by chemical means from the choices given is CO (Carbon monoxide). Carbon monoxide is a compound made up of carbon and oxygen and can therefore be broken by chemical means.
Hexa- means six
"hexa-" and it is in front of the fluoride so that means we have 6 fluorines
Answer:xenon hexafluoride → 
Any questions?
The molecule with same molecular formula but different arrangement of atoms is said to be an isomer.
When 2,2-dimethylbutane reacts with chlorine in the presence of light gives three isomers that is
(3-chloro-2,2-dimethylbutane),
(1-chloro-2,2-dimethylbutane) and
(1-chloro-3,3-dimethylbutane).
In above case, the molecular formula of all isomers are same i.e.
but chlorine is arranged in different positions of carbon. Thus, results isomers.
The reaction is shown in the image.