Chapter 11, Problem 68A

(a)

Interpretation Introduction

Interpretation:

Salt water needs to be classified as an element, compound, homogeneous, heterogeneous mixture, or substance.

Concept Introduction:

A mixture consists of different chemical substances that are not chemically bonded. A mixture can be homogeneous or heterogeneous. A homogeneous mixture is one in which the composition remains uniform throughout the mixture whereas, a heterogeneous mixture is one in which the composition is not uniform.

Answer to Problem 68A

Saltwater is a homogeneous mixture.

Explanation of Solution

Saltwater is a homogeneous mixture as the composition remains uniform throughout the solution. The salt does not form any layer when mixed in the water.

(b)

Interpretation Introduction

Interpretation:

Sodium chloride needs to be classified as an element, compound, homogeneous, heterogeneous mixture, or substance.

Concept Introduction:

A mixture consists of different chemical substances that are not chemically bonded. A mixture can be homogeneous or heterogeneous.

Answer to Problem 68A

Sodium chloride is a compound.

Explanation of Solution

A compound is a mixture of two or more elements present in fixed ratios. Sodium chloride is also a compound as it is made up of two elements that are sodium and chlorine in a 1:1 ratio.

(c)

Interpretation Introduction

Interpretation:

Air needs to be classified as an element, compound, homogeneous, heterogeneous mixture, or substance.

Concept Introduction:

A mixture consists of different chemical substances that are not chemically bonded. A mixture can be homogeneous or heterogeneous. A homogeneous mixture is one in which the composition remains uniform throughout the mixture whereas, a heterogeneous mixture is one in which the composition is not uniform.

Answer to Problem 68A

Air is a homogeneous mixture.

Explanation of Solution

Air consists of different gases that are not chemically bonded and the composition is uniform throughout. Therefore, the air is a homogeneous mixture.

(d)

Interpretation Introduction

Interpretation:

Salt and sand need to be classified as an element, compound, homogeneous, heterogeneous mixture, or substance.

Concept Introduction:

A mixture consists of different chemical substances that are not chemically bonded. A mixture can be homogeneous or heterogeneous. A homogeneous mixture is one in which the composition remains uniform throughout the mixture whereas, a heterogeneous mixture is one in which the composition is not uniform.

Answer to Problem 68A

Salt and sand are heterogeneous mixtures.

Explanation of Solution

Salt and salt are different substances and when mixed their composition does not remain constant throughout the mixture. Hence, salt and sand form a heterogeneous mixture.

(e)

Interpretation Introduction

Interpretation:

Gold needs to be classified as an element, compound, homogeneous, heterogeneous mixture, or substance.

Concept Introduction:

A mixture consists of different chemical substances that are not chemically bonded. A mixture can be homogeneous or heterogeneous. An element is a substance that is made up of only one type of atom.

Answer to Problem 68A

Gold is an element.

Explanation of Solution

Gold is an element because it is composed of only one type of atom, which is gold.

(f)

Interpretation Introduction

Interpretation:

Water with ice needs to be classified as an element, compound, homogeneous, heterogeneous mixture, or substance.

Concept Introduction:

A mixture consists of different chemical substances that are not chemically bonded. A mixture can be homogeneous or heterogeneous. A homogeneous mixture is one in which the composition remains uniform throughout the mixture whereas, a heterogeneous mixture is one in which the composition is not uniform.

Answer to Problem 68A

Ice with water is a heterogeneous mixture.

Explanation of Solution

Ice is a solid state of water; when ice is added to water, it forms a heterogeneous mixture as the composition is not uniform throughout the mixture.