37. Which of the following is an example of a physical change?
Answer: C
Ice melting is an example of a physical change.
Ice melting transforms from a solid state to a liquid state without altering its chemical composition, making it a clear example of a physical change.
A) Firewood burning
Firewood burning is a chemical change, as it transforms the wood into ash, carbon dioxide, and water vapor, fundamentally altering its chemical structure.
B) A nail rusting
A nail rusting is also a chemical change because it involves the reaction of iron with oxygen and moisture, resulting in the formation of iron oxide, which is a different substance altogether.
C) Ice melting
Ice melting is a physical change since the process of melting only changes the state of water from solid to liquid without changing its molecular structure, which remains H2O.
D) A hamburger frying
A hamburger frying represents a chemical change, as the heat causes complex chemical reactions that alter the proteins and fats, resulting in new substances and flavors.
Conclusion
Ice melting stands out as the only correct example of a physical change among the options provided, as it retains the original substance's chemical identity. In contrast, the other options involve processes that change the chemical makeup of the materials involved, categorizing them as chemical changes.