[baseballer10p]

Hello,
     I have to make a Beer's Law plot with absorbance against concentration of Cu2+ ion.  The problem is, I don't know how to figure out the concentration of the Cu2+ ion in my copper complex.  All I have is the mass of the complex and the absorbance of the solution.  Part of my data looks like this:
 
mass of Cu complex             H2O (mL)             Ammonia (mL)                        Absorbance
            .046g                       7.0                         3.0                                       1.085

I can't find a way to calculate the concentration of the Cu2+ ion from this.  Can anyone help me?

[enahs]

A plot would indicate you have more then one data point(s).


Beer's law is by definition giving you the concentration, it relates the absorbance as a function of concentration, path length and a constant.


So, what did you exactly do in this experiment and why are you having trouble calculating the concentration?

[baseballer10p]

I made five standard solutions of a copper complex and three unknown solutions of a copper complex.  Then the absorbance was measured for each solution.  I need to make a Beer's Law Plot for the standards.  For this I need to know the concentration of the standards, because I need to plot Absorbance vs. Concentration.  I am then supposed to use the slope I get from the trendline of the Beer's Law plot from the standards to calculate the concentration of the unknown solutions.  My whole table looks like this.



I have to make a beer's law plot from the standards, and find the concentration of the unknowns using the slope from the beer's law plot.

[Sam (NG)]

What salt did you use to make the standard solutions?

[baseballer10p]

I made the solution by dissolving Cu(NH3)n(SO4)n in 5mL of water and 5mL of ammonia.