Final answer:
Sucrose and lactose have the same chemical formula (C12H22O11), but they are different disaccharides made up of different monosaccharides. This difference in composition leads to different properties and behaviors.
Step-by-step explanation:
Sucrose and lactose have the same chemical formula, C12H22O11, but they have different characteristics and behave differently in chemical reactions because they are different disaccharides made up of different monosaccharides. Sucrose is made up of glucose and fructose, while lactose is made up of glucose and galactose. The different arrangements of the monosaccharides in each disaccharide result in different properties and behaviors.