Chapter 2, Problem 73A

(a)

Interpretation Introduction

Interpretation: Whether the blue-gray color of silicon is its chemical or physical property needs to be determined.

Concept Introduction: When a substance changes its appearance or change in the state takes place and there is no change in its chemical composition, the change is said to be physical. On the other hand, when there is a change in the chemical composition of a substance or a new substance is formed after a chemical reaction, it is known as a chemical change.

Answer to Problem 73A

Physical property.

Explanation of Solution

The color of any substance is its physical appearance. It does not affect its reaction with any other substance; thus, it is a physical property.

(b)

Interpretation Introduction

Interpretation: Whether the brittle nature of silicon is its chemical or physical property needs to be determined.

Concept Introduction: When a substance changes its appearance or change in the state takes place and there is no change in its chemical composition, the change is said to be physical. On the other hand, when there is a change in the chemical composition of a substance or a new substance is formed after a chemical reaction, it is known as a chemical change.

Answer to Problem 73A

Physical property.

Explanation of Solution

A substance is said to be brittle if it tends to deform or slightly change its shape before rapture when subjected to stress. It does not involve any chemical reaction; thus, it is a physical property.

(c)

Interpretation Introduction

Interpretation: Whether the property of silicon that it doesn’t dissolve in water is its chemical or physical property needs to be determined.

Concept Introduction: When a substance changes its appearance or change in the state takes place and there is no change in its chemical composition, the change is said to be physical. On the other hand, when there is a change in the chemical composition of a substance or a new substance is formed after a chemical reaction, it is known as a chemical change.

Answer to Problem 73A

Physical property.

Explanation of Solution

Whether a substance is soluble in water or not can be determined without changing its composition. Thus, it is a physical property. Here, silicon does not dissolve in water or it is not soluble in water, which is a physical property.

(d)

Interpretation Introduction

Interpretation: Whether the property of silicon that it melts at $1410{}^{\text{o}}\text{C}$ is its chemical or physical property needs to be determined.

Concept Introduction: When a substance changes its appearance or change in the state takes place and there is no change in its chemical composition, the change is said to be physical. On the other hand, when there is a change in the chemical composition of a substance or a new substance is formed after a chemical reaction, it is known as a chemical change.

Answer to Problem 73A

Physical property.

Explanation of Solution

The property of a substance that can be determined without changing its chemical composition is a physical property. Here, the melting point of the silicon can be determined by changing its chemical composition, it only changes its state thus, it is a physical property.

(e)

Interpretation Introduction

Interpretation: Whether the vigorous reaction of silicon with fluorine is its chemical or physical property needs to be determined.

Concept Introduction: When a substance changes its appearance or change in the state takes place and there is no change in its chemical composition, the change is said to be physical. On the other hand, when there is a change in the chemical composition of a substance or a new substance is formed after a chemical reaction, it is known as a chemical change.

Answer to Problem 73A

Chemical property.

Explanation of Solution

If a reaction is involved, it is a chemical property. Here, the nature of the reaction between silicon and fluorine can be only determined after performing the chemical reaction; thus, it is a chemical property.