Which of the following is a physical property of a substance? a. hardness b. flammability c. reactivity d. toxicity

The physical property of a substance among the options is; Choice A: Hardness

The physical properties of a substance include properties which can be assessed about a substance without the substance going through any change.

On the other hand, chemical properties of a substance are properties which can only be assessed after the substance undergoes a chemical change..

Hence, Hardness is the only physical property of a substance among the options above.

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A. Hardness

Explanation:

Physical property is those that can be observed without changing the substance directly. This includes hardness, color, volume, etc.

Chemical property is observed by changing the chemical identity of the substance, for example, corrosion, oxidation, etc. Flammability, Reactivity, and Toxicity all fall under this category.

the atomic mass is the bottom number on the element.

-steel jelly

the answer to your question is c