Question

When biuret reagent is added to a solution containing protein, the solution turns pink or purple. In the absence of protein, the solution is blue. Bluret reagent was added to solutions that may or may not contain protein. The data can be seen in the table below. What is the dependent variable in this experiment?

Tube Result
A Blue
B Blue
C Blue
D Purple

O the color change from blue to purple
O whether or not biuret reagent is added to the solution
O the pH of the solution
O the contents of the unknown solution

Answer 1

The dependent variable in the experiment where biuret reagent is added to a solution to test for proteins is the color change from blue to purple.

Step-by-step explanation:

When conducting an experiment with biuret reagent to test for the presence of proteins, the dependent variable would be the factor that is being measured or observed; in this case, it is the color change of the solution. When biuret reagent is added to a solution, it will turn pink or purple if proteins are present, indicating a positive result. If the solution remains blue, this indicates a negative result for proteins. Thus, the dependent variable here is the color change from blue to purple after adding biuret reagent to the solutions.