Final answer:
The known aspect of the standard riboflavin solution is its concentration. After dilution, the new concentration is calculated and the absorbance is measured with a Spec20, following the Beer-Lambert law.
Step-by-step explanation:
In this experiment, the missing word that describes what is known about the standard riboflavin solution is its concentration. When making dilutions, you will calculate the new concentration of these dilutions. Then, using a Spectronic 20 (commonly referred to as Spec20), you will measure the absorbance, which correlates with the concentration of the solution based on the Beer-Lambert law. The Beer-Lambert law states that absorbance is proportional to concentration and path length, which helps in determining concentrations of solutions. Understanding concentration and absorbance is essential in chemistry, particularly when working with solutions and performing quantitative analysis. Knowledge of how to prepare dilutions and measure absorbance allows chemists to accurately determine the concentration of unknown samples.