Question

1. classify the following properties of the element silicon as chemical or physical properties: a. blue-gray color b. brittle c. doesn’t dissolve in water d. melts at 1410°c e. reacts vigorously with fluorine

Explanation:

To solve this, we recall the definitions:

• Physical property: Observed/measured without changing the substance’s chemical identity (e.g., color, state, melting point, hardness, solubility in non - reactive solvents like water for some cases).
• Chemical property: Describes how a substance reacts with other substances (involves chemical change).

Part (a)

Step 1: Analyze the property type

Color is a physical property as it can be observed without altering the chemical identity of silicon.

Answer:

Physical property

Part (b)

Step 1: Analyze the property type

Brittleness (a measure of how easily a substance breaks) is a physical property. It is determined by the physical structure of the substance and does not involve a chemical reaction.