Respuesta :

1 mole MgCl2 is 95.211g

Set up the equation to solve for x

x moles = 321g
______    _____
1 mole = 95.211g

(pretend those are fractions!) :)

solve for x (so divide 321/95.211) = 3.37145918 moles
Likely round it to 2 decimals: 3.37moles
Moles = mass/mr

Mr of MgCl2 = 95

Moles=321g/95
=3.37894736842
=3.4 (rounded to 1 d.p)