Question

multiple choice 1 point
how many atoms are in 2.17 moles of strontium?
3.04 x10^23
4.03 x10^23
2.05 x10^23
1.31 x10^24

Explanation:

Step1: Recall Avogadro's number

Avogadro's number ($N_A$) is $6.022\times 10^{23}$ atoms/mol.

Step2: Calculate the number of atoms

We use the formula $N = n\times N_A$, where $n = 2.17$ mol. So $N=2.17\times6.022\times 10^{23}$.
$N=(2.17\times6.022)\times 10^{23}=13.06774\times 10^{23}=1.306774\times 10^{24}\approx1.31\times 10^{24}$

Answer:

1.31×10²⁴ (corresponding to the last option)