Chapter 1, Problem 1.1VP

Interpretation Introduction

To identify:

The class of pure substance and its physical state.

Answer to Problem 1.1VP

Solution:

Image (a) depicts a compound in the gaseous state. Image (b) depicts two different elements, one in solid state and the other in gaseous state.

Explanation of Solution

An element consists of only one type of atoms. A compound consists of two or more types of elements joined by chemical bonds.

When the atoms are widely separated, it represents gaseous state. When the atoms are closely arranged in a certain fixed pattern, it represents solid state.

In figure (a), there are molecules made up of two atoms each. The two atoms are not identical; they are shown by different colors. So the substance shown in figure (a) is a compound. The molecules are widely separated from each other. So, the physical state of the compound is gaseous.

In figure (b), there are red colored atoms arranged very close to each other in a regular arrangement. This is an element as all the atoms are of the same type. The physical state is solid. The blue colored atoms are widely separated from each other. This is also an element; it has the same type of atoms. The physical state is gaseous.

Conclusion:

The class of each substance and its physical state are identified. When the atoms are widely separated, it represents gaseous state. When the atoms are arranged closely and regularly, it represents solid state. A single color shows atoms of the same element; two different colors show atoms of two different elements.