Final answer:
A physical property is a characteristic of a substance that can be observed or measured without changing the identity of the substance. In a salt water solution, you can change physical properties such as density and boiling point by altering the concentration or temperature of the solution, without altering the chemical nature of the salt water.
Step-by-step explanation:
A physical property is a characteristic of a substance that can be observed or measured without changing the identity of the substance. Examples of physical properties include color, density, hardness, and melting and boiling points.
In the case of a saltwater solution, you can change two different physical properties without altering the chemical nature of the saltwater. One way is by changing the concentration of the solution. For example, by adding more salt to the water, you can increase the concentration and make the solution more concentrated. Another way is by changing the temperature of the solution. By heating the solution, you can increase the temperature and make it hotter.
Both of these changes affect physical properties such as density and boiling point, but they do not alter the chemical composition of the salt water.