Answer:
In 48.6 grams of Mg there are [tex]1.20*10^{24}[/tex]
Explanation:
A simple way to obtain the amount of atoms is by means of rules of three:
On one hand, you know the molar mass of Mg: 24.3 g / mol. This means that in one mole of Mg there are 24.3 grams. But you have 48.6 grams, so you must determine how many moles are that amount of mass. As mentioned earlier, you can calculate it using a rule of three: if there are 24.3 grams in a mole, how many moles are 48.6 grams?
[tex]moles of Mg=\frac{48.6g*1mol}{24.3g}[/tex]
moles of Mg=2 moles
On the other hand, you know that in one mole of Mg there are [tex]6.02*10^{23}[/tex] atoms. And you know that 48.6 grams are 2 moles. Then, you can reapply a simple rule of three: if in one mole there are [tex]6.02*10^{23}[/tex] atoms, how many atoms are in 2 moles?
[tex]number of atoms=\frac{2moles*6.02*10^{23} atoms}{1mol}[/tex]
number of atoms=[tex]1.20*10^{24}[/tex]
Finally, you can say that in 48.6 grams of Mg, which are 2 moles, there are [tex]1.20*10^{24}[/tex]
