Chapter 3, Problem 18PE

(a)

Interpretation Introduction

Interpretation:

Dirt has to be classified as a compound or an element.

Concept Introduction:

Pure substance:  A single component that has a constant composition, irrespective of the sample size and the sample origin is called as pure substance.  A pure substance could not be broken down to other pure substances by any physical change.

Example:  Water, sugar etc.

A pure substance can be classified into an element and a compound.

Element:  A pure substance, which cannot be broken down into smaller substances by a chemical reaction is called as an element.

Example:  Hydrogen gas, Magnesium ribbon and copper wire etc.

Compound:  A pure substance that is formed by combination of two or more elements by chemical process is called as a compound.  Example:  Sodium chloride is a compound because it is formed from elements sodium and chlorine.

(b)

Interpretation Introduction

Interpretation:

Salad dressing has to be classified as a compound or an element.

Concept Introduction:

Refer to part (a).

(c)

Interpretation Introduction

Interpretation:

Tungsten has to be classified as a compound or an element.

Concept Introduction:

Refer to part (a).

(d)

Interpretation Introduction

Interpretation:

Dinitrogen monoxide has to be classified as a compound or an element.

Concept Introduction:

Refer to part (a).

(e)

Interpretation Introduction

Interpretation:

Brass has to be classified as a compound or an element.

Concept Introduction:

Refer to part (a).

(f)

Interpretation Introduction

Interpretation:

Egg has to be classified as a compound or an element.

Concept Introduction:

Refer to part (a).