Here's why:
* Physical properties can be observed without altering the substance's chemical makeup. Examples include color, density, melting point, boiling point, and conductivity. You can observe these properties without changing what the substance is.
* Chemical properties describe how a substance reacts with other substances or changes its composition under certain conditions. These properties can only be observed by changing the chemical makeup of the substance. Examples include flammability, reactivity with acids, and decomposition.
Let's take an example:
* Water (H₂O) is a clear, colorless liquid. These are physical properties that we can observe without changing the water.
* However, if we add sodium (Na) to water, a chemical reaction occurs, producing sodium hydroxide (NaOH) and hydrogen gas (H₂). This is a chemical property because we've changed the composition of the water, forming new substances.
In essence, to observe a chemical property, you must perform a chemical reaction that changes the substance's molecular structure.
