The correct answer is:
A. Physical, the gaseous water produced is chemically identical to the liquid water the process began with.
Explanation:
Boiling Water: When water is boiled, it changes from a liquid state to a gaseous state (steam). This is a phase change, which is a characteristic of physical changes.
Chemical Identity: The water molecules (H₂O) remain chemically the same before and after boiling. The process does not alter the chemical structure of the water molecules; it simply changes their state. Therefore, both the liquid water and the steam produced are composed of the same H₂O molecules.
Physical vs. Chemical Changes:
Physical Change: A change that affects one or more physical properties of a substance but does not change its chemical composition. Examples include changes in state (like melting, freezing, boiling).
Chemical Change: A change that results in the formation of new chemical substances. This would involve a chemical reaction where the original substances are transformed into different substances.
Analysis of Other Options:
B. Physical, the water was disappeared: This is incorrect because the water doesn’t disappear; it simply changes state.
C. Chemical, the heat was required for the change: While heat is needed for boiling, it does not indicate a chemical change. Many physical changes also require heat.
D. Chemical, the process produced a gas: Producing a gas alone does not indicate a chemical change. For example, when water boils, it produces steam, but the steam is still water in a gaseous form.
In conclusion, boiling water is a physical change since the chemical identity of water remains unchanged throughout the process.
