Respuesta :
Answer:
2.91 grams of Magnesium
Explanation:
I put a picture . I used the molar mass of magnesium which can be calculated from the periodic table or simply google it. :) I hope it helps - Enrique

You first take the weighed out amount of magnesium then you divide by the actual mass of magnesium 24.305 g. 70.8/24.305 = 2.912980868134129. Then you multiply by Avagadros number 6.02x10^23. 2.9129 x 6.02x10^23 = 1.753614482617^24. Then round it to 1.75^24 moles of magnesium