What is the mass of MgCl2 required to make 500mL if 1.200 M of MgCl2 Solution?

I'm having trouble figuring out what the equation looks like. I believe the answer is 57.127g but if so i would like to know why.

I did (1.200M*.500mL)/1000* mass of MgCl2.

How do i find how many liters are in 1.2M of MgCl2?