Koliki je broj molekula klora u uzorku mase 2,00 kg?

Elementarni klor nalazi se u obliku dvoatomnih molekula $\text{Cl}_2$$\text{Cl}_2$ čija je molarna masa $M(\text{Cl}_2) = 2 \cdot 35{,}45\text{ g mol}^{-1} = 70{,}90\text{ g mol}^{-1}$$M(\text{Cl}_2) = 2 \cdot 35{,}45\text{ g mol}^{-1} = 70{,}90\text{ g mol}^{-1}$.
Zadana je masa uzorka $m(\text{Cl}_2) = 2{,}00\text{ kg} = 2000\text{ g}$$m(\text{Cl}_2) = 2{,}00\text{ kg} = 2000\text{ g}$.
Broj molekula klora izračunavamo povezivanjem mase, molarne mase i Avogadrove konstante pomoću izraza $N(\text{Cl}_2) = \frac{m(\text{Cl}_2)}{M(\text{Cl}_2)} \cdot N_A$$N(\text{Cl}_2) = \frac{m(\text{Cl}_2)}{M(\text{Cl}_2)} \cdot N_A$:
$N(\text{Cl}_2) = \frac{2000\text{ g}}{70{,}90\text{ g mol}^{-1}} \cdot 6{,}022 \times 10^{23}\text{ mol}^{-1} = 1{,}70 \times 10^{25}$$N(\text{Cl}_2) = \frac{2000\text{ g}}{70{,}90\text{ g mol}^{-1}} \cdot 6{,}022 \times 10^{23}\text{ mol}^{-1} = 1{,}70 \times 10^{25}$
Odgovor: D