Step-by-step explanation:
To calculate the mass of copper(II) sulfate added to the flask, we need to use the formula:
mass = volume x concentration x molar mass
where:
volume = 85.0 mL = 0.0850 L (converted to liters)
concentration = 0.51 M
molar mass of CuSO4 = 159.61 g/mol (from the periodic table)
Substituting the values into the formula, we get:
mass = 0.0850 L x 0.51 mol/L x 159.61 g/mol
mass = 6.68 g
Therefore, the chemist has added 6.68 grams of copper(II) sulfate to the flask.