Which explains the basis of the biuret test?
a) sudan iii dye binds to lipids and changes color
b) a blue dye binds to protein and changes color
c) under base conditions, copper ions bind to the amino groups of proteins and change color
d) iodine fits into the coils of starch polymers and changes colors

The correct answer is C) under base conditions, copper ions bind to the amino groups of proteins and change color. This test is a chemical one, which means it's testing the chemical properties of an object, specifically to detect peptide bonds. When these bonds are detected, an ion called copper II will bind (as the answer indicates), and will change the blue color of biuret into a violet color.

It is a mixture. simply put, a compound must be pure, that is, of only one chemical structure and composition. a mixture is made of different chemical substances (i.e. elements, molecules, compounds) that are not chemically bonded to each other, but instead physically grouped together, as in the case of gasoline (a homogeneous solution).

Answer charle's law