Is milk a mixture of pure substance -why and if it is a mixture what two types of substance does it contains
The Correct Answer and Explanation is:
Yes, milk is a mixture, not a pure substance. A pure substance consists of only one type of particle, such as elements or compounds, whereas a mixture contains two or more different types of particles that are physically combined but not chemically bonded. Milk is a heterogeneous mixture because it contains a variety of substances that are not chemically bonded, and its composition can vary slightly depending on its source and processing.
Milk contains both homogeneous and heterogeneous components. The two primary types of substances it contains are:
- Water (H2O): The major component of milk, making up about 87% of its composition. Water is a solvent, and it dissolves many of the other components in milk. It also helps in transporting nutrients within the body once consumed.
- Fat globules (lipids): These are suspended in the water and are what make milk creamy. Milk fat is in the form of tiny globules that are distributed throughout the liquid, and depending on the type of milk (whole milk, skim milk, etc.), the amount of fat will vary.
Additionally, milk contains other substances, including proteins (such as casein and whey), lactose (milk sugar), minerals (such as calcium and magnesium), vitamins (like vitamin A and B12), and traces of other elements.
While milk appears homogeneous to the naked eye, it’s actually a colloidal suspension, meaning the fat particles are dispersed in the water, but they don’t dissolve in it. The fat globules may separate from the liquid if milk is left standing or if it undergoes certain processes like pasteurization or homogenization. In this sense, milk is considered a complex mixture with various phases, and its components can be physically separated, confirming that it is not a pure substance.
