How many grams of copper II fluoride are needed to make 6.7 L of a 1.2 M solution?

In 1 litre you have 1.2 moles CuF2

So 6.7 litres you have 6.7 X 1.2 = 8.04 moles CuF2

The Mr ( Relative Molecular Mass of CuF2) is

1 x Cu = 1 x 63.5

2 x F = 2 x 19 = 38

63.5 + 38 = 101.5 )Mr pf CuF2)

Moles = mass)g) / Mr

Hence

mass = moles X Mr

mass = 8.04 X 101.5 = 816.06 grams. ( is required).