Question

How many grams of Manganous sulfate (MnSO4) do you need to dissolve in 500.00 mL of DDI water to make a stock solution of 0.350 mg/mL in manganese? (i.e., so that the concentration of manganese cation is 0.250 mg/mL). MW of MnSO4 is 120.37 g/mol; AW of Mn is 54.9380 g/mol.

Answer 1

mass of Mn = 0.350 mg/mL   *   500 mL

                   = 175 mg

                   = 0.175 g

Mn    + H2SO4 ----------------------------> MnSO4

54.9380 g                                                                   120.37 g

0.175 g                                                                             ?

54.9380 g Mn ------------------------------> 120.37 g MnSO4

0.175 g Mn ---------------------------------> X g MnSO4

X   = 0.175 x 120.37 / 54.9380

X = 0.383 g

Manganous sulfate (MnSO4)   = 0.383 g