convert 400 grams of MgCl2 to moles

Question

the only details I have are that you have 400 grams and you will need to convert that to moles

Answer 1

molar mass MgCl2 = 24.3 + 2x35.5 = 95.3 g/mole

400 g x 1 mole/95.3 g = 4.19 moles = 4 moles (to 1 significant figure)