Question

How many atoms of Mg are present in 97.22 grams of Mg?

6.022 × 1023
2.408 × 1024
4.818 × 1024
5.855 × 1025

Answer 1

Answer: Option (b) is the correct answer.

Step-by-step explanation:

It is given that mass of Mg is 97.22 g and it is known that molar mass of Mg is 24.305 g/mol.

So, calculate the number of moles as follows.

No. of moles =
`(mass given in grams)/(Molar mass)`

=
`(97.22 g)/(24.305 g/mol)`

= 4 mol

Also, it is known that 1 mole has
`6.023 * 10^(23)` atoms/mol. Therefore, calculate the number of atoms in 4 mol as follows.

`4 mol * 6.023 * 10^(23) atoms/mol`

=
`24.08 * 10^(23)` atoms

or, =
`2.408 * 10^(23)` atoms

Thus, we can conclude that there are
`2.408 * 10^(23)` atoms in 97.22 grams of Mg.