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 = \(\frac{mass}{\text{molar mass}}\)
0.20 mol = \(\frac{mass}{10.8 g/mol}\)
= 2.16 g
And, according to the mole concept there are \(6.022 \times 10^{23} atoms\) present in 1 mole of a substance.
Mathematically, 1 mole = \(6.022 \times 10^{23}\) atoms or molecules
Therefore, calculate the number of atoms present in 0.20 mol of boron as follows.
\(0.20 \times 6.022 \times 10^{23}}atoms /mol\)
= \(1.204 \times 10^{23}\) atoms
Thus, we can conclude that mass of boron is 2.16 g and it contains \(1.204 \times 10^{23}\) atoms.
