Answer:
b. 0.47 moles Ca.
Explanation:
Hello there!
In this case, since 1 mole of any element contains 6.022x10²³ atoms of the same, it is possible for us to compute the moles in 2.8x10²³ atoms of calcium via the Avogadro's number:
[tex]2.8x10^{23}atomsCa*\frac{1molCa}{6.022x10^{23}atomsCa}\\\\=0.47molCa[/tex]
Therefore, the answer would be b. 0.47 moles Ca.
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