How many grams of ammonium sulfate (MW 132.1) are needed to make 1.5 L of an 8 M solution?

Use the compbined equation

mass(g) / Mr = [conc] x vol(mL) / 1000 ( = moles)

Algebraically rearrange

mass(g) = Mr X [conc] x vol(mL)/1000

Substituting

mass(g) = 132.1 x 8Mol/L x 1500 mL/ 1000 = 1585.2 g

or 1.5852 kg

NB The '1000' is used to convert the units of L(itres) in 'M' to mL.