Which of the following best explains why whipping egg whites is considered a physical change?

• A. Whipping egg whites produces new chemical substances.
• B. Whipping egg whites results in a permanent change in their chemical identity.
• C. Whipping egg whites causes the proteins to break down into amino acids.
• D. Whipping egg whites changes their appearance and texture without altering their chemical composition.

Answer: (D)

Verified step by step guidance

1. Understand the difference between physical and chemical changes: A physical change affects the form or appearance of a substance without changing its chemical composition, while a chemical change results in the formation of new substances with different chemical properties.
2. Consider what happens when egg whites are whipped: The process incorporates air and causes the proteins to unfold and form a foam, changing the texture and appearance.
3. Analyze whether the chemical composition of the egg whites changes during whipping: The proteins are not broken down into amino acids, nor are new chemical substances formed; the molecules remain chemically the same.
4. Recognize that the change is reversible in principle (e.g., by heating or other means), which is characteristic of physical changes rather than chemical changes.
5. Conclude that whipping egg whites is a physical change because it alters the physical properties (texture and appearance) without changing the chemical identity of the proteins.