Answer: The correct choice is (b).
Explanation:
We have the mass of Magnesium at 97.22 g, and the molar mass of Magnesium is 24.305 g/mol.
Therefore, the calculation for the number of moles is as follows.
Number of moles = 
=
= 4 mol
Additionally, it is known that one mole contains
atoms/mol. Thus, we calculate the total number of atoms in 4 moles as follows.

=
atoms
or, =
atoms
Hence, we conclude that in 97.22 grams of Magnesium, there are
atoms.
Although I may not be the smartest, I can definitely answer.
This represents a chemical change because the substances' chemical identities were altered. The fizzing was a clear sign, and the temperature increase was another indicator of the reaction.
The compound is acetone ( CH₃-CO-CH₃)
Explanation:
1) Acetone is represented as CH₃-CO-CH₃.
2) This is a molecule formed by covalent bonds.
3) When it dissolves, compounds with covalent bonds remain as individual molecules, indicating that the primary species in the solution are the molecules themselves, which are surrounded (solvated) by water molecules.
In contrast, ionic compounds ionize. For example, when NaCl dissolves in water, it completely breaks down into ions, hence the predominant species are the ions Na⁺ and Cl⁻, rather than the NaCl formula.
This leads to the conclusion that: when acetone dissolves in water, the primary components are the acetone molecules (there is no need to mention that water molecules are in the solution, as that isn't the question's focus).
M = 81.50g, mm = m/n
n =???
PV = nRT --> n = PV/RT
n = (1.75)(4.92)/(.0821)(307)
n = 8.61/25.20 =.342
--> mm = m/n = 81.5/.342 = 238.58