To determine the chemical property of aluminum from the given options, we first need to understand the difference between physical and chemical properties.
Physical properties are characteristics that can be observed or measured without changing the composition or identity of the substance. Examples include density, color, and hardness.
Chemical properties, on the other hand, describe the substance's ability to undergo changes that transform it into different substances. These changes usually involve chemical reactions or the reactivity of the substance.
Let's analyze each option:
1. Aluminum has a density of [tex]$2.70 g \cdot cm ^{-3}$[/tex]: This is a physical property because density is a measure of mass per unit volume and does not involve a change in the chemical composition of aluminum.
2. Aluminum is silvery white in color: This is a physical property because color is a characteristic that can be observed without changing the chemical structure of aluminum.
3. Aluminum is highly reactive: This is a chemical property. Reactivity refers to the ability of aluminum to chemically react with other substances, which involves changes to its chemical structure.
4. Aluminum is a soft metal: This is a physical property because it describes a characteristic (hardness) that does not alter the chemical composition of aluminum.
Given these explanations, the correct answer is:
Aluminum is highly reactive.
This property describes aluminum's ability to participate in chemical reactions, indicating it is indeed a chemical property.
