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

Answer: 816.40572 grams CuF2 OR 820 grams CuF2 (with sigfigs)

Explanation: To find the amount in grams, you first have to find it in moles and use the molar mass as a conversion factor to convert it into grams. To find the amount in moles you must switch around the formula for molarity. Molarity = number of moles / volume or M = n/V. As you can see, the unit for molarity is M or moles/liter and the units for volume is liters. All you have to do is switch the equation around so you are solving for number of moles, or n. The switched equation looks like n = MV. So, you just have to multiply the amount of liters and the molarity and then convert to grams. 6.7 liters*1.2 moles/liter = 8.04 moles CuF2 (the liters cancel out). Then you have to convert to moles: 8.04 moles CuF2*101.543 grams/mol CuF2 = 816.40572 grams CuF2. If you want the answer with significant figures, it would be 820 grams CuF2.