Question

how many moles are in 5.2 x 10^{23} atoms of barium?
0.864 mol
3.1 x 10^{41} mol
0.15 mol
8.32 x 10^{24} mol

Explanation:

Step1: Recall Avogadro's number

Avogadro's number ($N_A$) is $6.022\times 10^{23}$ atoms/mol. The formula to convert number of atoms ($N$) to moles ($n$) is $n=\frac{N}{N_A}$.

Step2: Substitute values

Given $N = 5.2\times 10^{23}$ atoms. Then $n=\frac{5.2\times 10^{23}\text{ atoms}}{6.022\times 10^{23}\text{ atoms/mol}}$.

Step3: Calculate the result

$n=\frac{5.2}{6.022}\approx0.864$ mol.

Answer:

0.864 mol