I thinking the limitation is that a shifting electron will always move from a more excited states to a less excited state. Electrons could not circle the nucleus because they would lose energy by emitting electromagnetic radiation and spiral into the nucleus. In addition Bohr was not able to explain electrons orbits of large atom w/many electrons.
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.
Answer:
<h2>0.15 moles</h2>
Explanation:
To find the number of moles in a substance given it's number of entities we use the formula

where n is the number of moles
N is the number of entities
L is the Avogadro's constant which is
6.02 × 10²³ entities.
From the question we have

We have the final answer as
<h3>0.15 moles</h3>
Hope this helps you