Chapter 17, Problem 13A

a. Cite an example of a substance that is made of molecules.

b. Cite a substance that is made of atoms rather than molecules.

To determine

To write: An example of substance made of molecule.

Explanation of Solution

Introduction:

When two or more atoms of different or same elements combines together, a molecule is formed. Their chemical and physical properties are different from the elements from which they are formed.

The example of a substance that is made of molecules is water $\left(H_{2}O\right)$ . Here two atoms of Hydrogen and one atom of Oxygen combines to form water. But, the properties of water are entirely different from Hydrogen and Oxygen.

To determine

To write: An example of substance made of atoms.

Explanation of Solution

Introduction:

Atoms: For any substance or matter, the smallest unit is atom. It has similar chemical properties of elements. It consists of three subatomic particles except hydrogen atom.

The three sub-atomic particles are:

1. Electrons
2. Protons
3. Neutrons

The example of a substance that is made of atoms is Iron (Fe).

Here the iron is formed by only one atom.

Also, all the metals are the example of substance that is made of atoms.