Construct a standard curve (absorbance vs. concentration) using the following results.
A 5mL, 10mL, 15mL,20mL aliquot of 0.010M sodium salicylate solution was diluted to 100 mL in four different volumetric flasks with the Iron (III) chloride solution. The % Transmittance for the iron complex formed in each of these given solutios was 60.3%, 39.8%, 26.3%, and 15.1% respectively.
To construct a standard curve, you need to plot the absorbance values on the y-axis and the corresponding concentration values on the x-axis.
In this case, you are given the % transmittance values, which are inversely proportional to the absorbance values. To convert % transmittance to absorbance, you can use the following formula:
Absorbance (A) = -log(%T/100)
Now, you can begin constructing the standard curve:
1. Determine the concentration values. Since you diluted the 0.010M sodium salicylate solution in 100 mL, the final concentration of each aliquot can be calculated as follows:
For 5 mL aliquot: (0.010 M) x (5 mL / 100 mL) = 0.0005 M
For 10 mL aliquot: (0.010 M) x (10 mL / 100 mL) = 0.0010 M
For 15 mL aliquot: (0.010 M) x (15 mL / 100 mL) = 0.0015 M
For 20 mL aliquot: (0.010 M) x (20 mL / 100 mL) = 0.0020 M
2. Calculate the absorbance values using the % transmittance values and the formula mentioned earlier:
For 60.3% transmittance: A = -log(60.3/100)
For 39.8% transmittance: A = -log(39.8/100)
For 26.3% transmittance: A = -log(26.3/100)
For 15.1% transmittance: A = -log(15.1/100)
3. Plot the absorbance values (y-axis) against the corresponding concentration values (x-axis) on a graph.
4. Connect the plotted points with a line to obtain the standard curve.
Remember to label the axes and include appropriate units for concentration (e.g., M or mM), as well as units for absorbance (A or AU).