Question

masteryconnect
wilson, mak yla
dtal-ch-term 1 - unit 1 assessment - 25-26

a student examined a pure, unknown substance, then observed and measured its physical properties.

unknown substance

physical property	description or value
flammability	none
odor	sweet, distinctive odor
melting point	-22.7°c
boiling point	76.74°c
density at 20°c	1.885 g/cm³
water solubility at 20°c	6.08 g/100 g h₂o

which change should the student make to the data table?

• the student should remove density from the data table as it is not a physical property.
• the student should add reactivity to the data table as it is a physical property.
• the student should add corrosion to the data table as it is a physical property.
• the student should remove flammability from the data table as it is not a physical property.

Explanation:

To solve this, we recall the difference between physical and chemical properties. Physical properties can be observed or measured without changing the substance's chemical identity (e.g., color, density, melting/boiling point, solubility). Chemical properties relate to how a substance reacts (e.g., flammability, reactivity, corrosion) as they involve chemical changes.

• Density is a physical property (can be measured without altering the substance), so removing it is wrong.
• Reactivity is a chemical property, so adding it as a physical property is wrong.
• Corrosion is a chemical process (involves reactions), so adding it as a physical property is wrong.
• Flammability is a chemical property (involves burning, a chemical reaction), so it should be removed from the physical properties table.

Answer:

The student should remove flammability from the data table as it is not a physical property.