Answer:
1.46 moles
Step-by-step explanation:
You need to multiply 35.4g by Magnesium's molar mass.
Molar mass =1 mole/24.305g
(35.4g)(1 mole Mg/24.305g)= 1.46 moles <- rounded to 3 significant figures
As you can see, grams cancel out and you're left with moles.