Prepare a one-liter stock standard iron (II) solution by
accurately weighing 0.07 g of ferrous ammonium sulfate. What is the
Concentration of Stock Standard Iron (II) Solution in (mol/L) show
calculation please.
Standard 1 is prepared by diluting 1.00 mL of the stock iron
(II) solution to 100 mL. Standard 2 is prepared by diluting
2.00 mL of the stock iron (II) solution to 100 mL. Standard 3
is prepared by diluting 5.00 mL of the stock iron (II) solution to
100 mL. Standard 4 is prepared by diluting 10.00 mL of the
stock iron (II) solution to 100 mL. Standard 5 is prepared by
diluting 25.00 mL of the stock iron (II) solution to 100 mL.
Calculate the molarity of each standard and record it in the table
below.
Solution
Absorbance
Concentration (mol/L)
Blank
0.00
Standard 1
0.002
Standard 2
0.034
Standard 3
0.063
Standard 4
0.143
Standard 5
0.301
Our sample is a solid, weigh out accurately about 0.1 g,
dissolve it in 100.0 mL DI water. Then dilute 1.0 mL of this
original unknown solution to 100.0 mL by adding 1.0 mL of
hydroxylammonium chloride, 5.0 mL of 1,10-phenanthroline and 8.0 mL
of sodium acetate and 85.0 mL of DI water.
Absorbance of Diluted Unknown Solution
0.117
Concentration of Fe2+ Diluted (mol/L)
Concentration of Fe2+ In Original (mol/L)
Moles of Fe2+ in Original (mol)
Mass of Fe2+ in Original (g)
Mass of Original Solid Unknown (g)
0.1001
Mass Percent of Fe in Original Solid Unknown
Molar Absorptivity
Solution
Molar Absorptivity (L*mol-1*cm-1)
Standard 1
Standard 2
Standard 3
Standard 4
Standard 5
Average