Question

1. The preparation of nanoparticle solutions adds a reducing reagent, sodium borohydride, to an oxidizing agent, hydrogen peroxide. Is it concievable that these two reagents would react with each other? 2. Why is it important to force the regression line in the Beer's Law plot of absorbance vs. concentration to go through the origin? Would adding the point (0,0) to your data set have the same effect? Why or why not?

Answer 1

When solutions are transferred to a small, rectangular cuvette that is placed into the colorimeter. The amount of light that penetrates the solution and strikes the photocell is used to compute the absorbance of each solution. When a graph of absorbance vs. concentration is plotted for the solution, a direct relationship should result. The direct relationship between absorbance and concentration for a solution is known as Beer's law.

The concentration of an unknown solution is then determined by measuring its absorbance with the colorimeter. By locating the absorbance of the unknown on the vertical axis of the graph, the corresponding concentration can be found on the horizontal axis. The concentration of the unknown can also be found using the slope of the Beer's law curve.