Questions: Consider an experiment done by holding the amount of FeSO4 at 3.00 mL and varying the amount of o-phen solution. Sketch what the plot of Absorbance vs. mL o-phen would look like. (You do not need to show the exact values on the x and y axes, but your graph should accurately represent the shape that is to be expected). Label your axes.

Solution Steps

The experiment involves adding varying amounts of o-phenanthroline (o-phen) to a fixed amount of FeSO4. o-phen reacts with Fe²⁺ to form a colored complex. As the amount of o-phen increases, more of the complex forms.

Initially, as more o-phen is added, the absorbance increases linearly because more of the colored complex is formed. This is proportional to the increasing concentration of o-phen.

Once all the Fe²⁺ ions have reacted with o-phen, adding more o-phen won't form any more complex. This means the absorbance will plateau and remain constant, even with further additions of o-phen.

Final Answer:

      Absorbance
          |
          |        /------
          |       /
          |      /
          |     /
          |    /
          |   /
          |  /
          | /
          |/___________________
           mL o-phen