Question

multiple choice 1 point how many atoms are in 0.23 moles of calcium? 1.0x10^23 1.4x10^23 4.2x10^23 2.8x10^23

Explanation:

Step1: Recall Avogadro's number

Avogadro's number $N_A = 6.022\times 10^{23}\text{ atoms/mol}$.

Step2: Calculate the number of atoms

The number of atoms $N$ in a substance is given by $N = n\times N_A$, where $n$ is the number of moles. Here, $n = 0.23$ moles. So $N=0.23\times6.022\times 10^{23}$.
$N=(0.23\times6.022)\times 10^{23}=1.38506\times 10^{23}\approx1.4\times 10^{23}$.

Answer:

$1.4\times 10^{23}$ (corresponding to the second - option in the multiple - choice list)