Question 23

The melting of an ice cube in a glass of water is an example of a physical change.

When an ice cube melts in water, it undergoes a physical change from solid to liquid without altering its chemical composition. This process is a reversible change, characteristic of physical transformations.

A) physical change

This option is correct because melting is a physical change that involves a change in the state of matter. The chemical structure of water remains the same before and after the ice melts, confirming that it is a physical transformation.

B) chemical reaction

This option is incorrect as a chemical reaction involves a change in the chemical composition of substances, resulting in new substances being formed. In the case of melting ice, no new substances are created; thus, it does not qualify as a chemical reaction.

C) metabolic process

This option is also incorrect because metabolic processes refer to chemical reactions that occur within living organisms to maintain life. Melting ice does not involve any biological processes and is purely a physical change.

D) decay mechanism

This option is incorrect as well. A decay mechanism typically refers to the breakdown of organic matter or the decay of substances through biological or chemical means. The melting of ice does not fit this definition, as it does not involve decomposition or breakdown.

Conclusion

The melting of an ice cube is definitively classified as a physical change because it involves a transition between states of matter without altering the chemical identity of the substance. All other options fail to accurately describe the process, as they involve changes in chemical composition or biological functions that are not applicable in this context.