What is the molarity of a solution containing 121.8g of MgSO4 in 3.5L of solution?

Answer 1

First find how many moles of MgSO4 you have in 121.8g. You will need the molecular weight of MgSO4.

moles = mass of MgSO4 / mass of one mole of MgSO4 (molecular mass or molecular weight)

Then you find the molarity using the definition:

molarity = moles of MgSO4 / liters of solvent

This will give you the molarity of 121.8g MgSO4 in 3.5L of solvent.