Question

Spectrophotometric Analysis of Fe2+ using 1,10-phenanthroline

Given the following data, calculate the percent by mass Fe²⁺ in the unknown sample. Assume the experimental data provided is obtained using the same procedure you will be using in the lab.

Unknown sample mass = 0.1725

Absorbance (average) of unknown sample = 0.374

Beer’s Law Data:        Slope = 0.2203 L/mg Fe²⁺

                                    y-intercept = -0.001

**PREPARATION OF UNKNOWN FE2+ SAMPLE**

weighed 0.1725 g of the unknown sample into 100 mL beaker -> add about 30 mL of distilled water and 1 mL concentrated sulfuric acid -> transferred to 100 mL volumetric flask, then filled to mark with distilled water -> pipet 10.00 mL into second 100 mL volumetric flask and make up to the mark -> then pipette 10.00 mL into third 100 mL volumetric flask and add 10 mL saturated sodium acetate and 10 mL 10% hydroxylamine hydrochloride -> add 10 mL 0.1% 1,10-phenanthroline to the flask then fill to mark with distilled water

Answer 1