Answer:
Option C is correct.
The minimum amount of material that is needed for a fission reaction to keep going is called the critical mass.
Explanation:
Nuclear fission is the term used to describe the breakdown of the nucleus of a parent isotope into daughter nuclei.
Normally, the initial energy supplied for nuclear fission is the energy to initiate the first breakdown of the first set of radioactive isotopes that breakdown. Once that happens, the energy released from the first breakdown is enough to drive further breakdown of numerous isotopas in a manner that leads to more energy generation.
But, for this to be able to be sustained and not fizzle out, a particular amount of radioactive material to undergo nuclear fission must be present. This particular amount is termed 'critical mass'
Hope this Helps!!!
The formal charge on each atom can be known by counting up the number of valence electrons that is present on each atom.
<h3>What is Lewis structure?</h3>
The term Lewis structure is the representation of a compound using its symbols and showing the valence electrons as dots. This question is incomplete as the Lewis structures were not shown.
If it is shown, we can know the formal charge on each atom by counting up the number of valence electrons that is present on each atom.
Learn more about Lewis structure: brainly.com/question/4144781
Answer:
The mass fraction of ferric oxide in the original sample :
Explanation:
Mass of the mixture = 3.110 g
Mass of 
Mass of 
After heating the mixture it allowed to react with hydrogen gas in which all the ferric oxide reacted to form metallic iron and water vapors where as aluminum oxide did not react.

Mass of mixture left after all the ferric oxide has reacted = 2.387 g
Mass of mixture left after all the ferric oxide has reacted = y

The mass fraction of ferric oxide in the original sample :

I am positive it is the last one!