Explanation:
As molar mass of boron is 10.8 g/mol and it is given that its number of moles is 0.20 mol.
Therefore, calculate its mass as follows.
No. of moles = [tex]\frac{mass}{\text{molar mass}}[/tex]
0.20 mol = [tex]\frac{mass}{10.8 g/mol}[/tex]
= 2.16 g
And, according to the mole concept there are [tex]6.022 \times 10^{23} atoms[/tex] present in 1 mole of a substance.
Mathematically, 1 mole = [tex]6.022 \times 10^{23}[/tex] atoms or molecules
Therefore, calculate the number of atoms present in 0.20 mol of boron as follows.
[tex]0.20 \times 6.022 \times 10^{23}}atoms /mol[/tex]
= [tex]1.204 \times 10^{23}[/tex] atoms
Thus, we can conclude that mass of boron is 2.16 g and it contains [tex]1.204 \times 10^{23}[/tex] atoms.
