Chapter 8, Problem 40A

(a)

Interpretation Introduction

Interpretation: The number and kinds of atoms present in ascorbic acid (vitamin C) need to be determined.

Concept Introduction: Molecular formula tells about the total number of atoms of the element present in the molecule of a substance. It confirms the type of atoms as well the number of atoms of the same type present in the molecule. For example, the molecular formula of water is ${\text{H}}_{\text{2}}\text{O}$ ; thus, it can be seen that 1 water molecule contains 2 hydrogen atoms and 1 oxygen atom.

Explanation of Solution

The given compound is ascorbic acid with the molecular formula ${\text{C}}_{\text{6}}{\text{H}}_{\text{8}}{\text{O}}_{\text{6}}$ . From the molecular formula of the compound, it is clear that there are three kinds of atoms present in the compound that is carbon, hydrogen, and oxygen. Also, there are 6 carbon atoms, 8 hydrogen atoms, and 6 oxygen atoms thus, the total number of atoms in the compound will be $6+8+6=12$ .

Thus, the number of atoms and kind of atoms present in the molecule is 12 and 3 respectively.

(b)

Interpretation Introduction

Interpretation: The number and kinds of atoms present in sucrose (table sugar) need to be determined.

Concept Introduction: Molecular formula tells about the total number of atoms of the element present in the molecule of a substance. It confirms the type of atoms as well the number of atoms of the same type present in the molecule. For example, the molecular formula of water is ${\text{H}}_{\text{2}}\text{O}$ ; thus, it can be seen that 1 water molecule contains 2 hydrogen atoms and 1 oxygen atom.

Explanation of Solution

The given compound is sucrose acid with the molecular formula ${\text{C}}_{12}{\text{H}}_{22}{\text{O}}_{11}$ . From the molecular formula of the compound, it is clear that there are three kinds of atoms present in the compound that is carbon, hydrogen, and oxygen. Also, there are 12 carbon atoms, 22 hydrogen atoms, and 11 oxygen atoms; thus, the total number of atoms in the compound will be $12+22+11=45$ .

Thus, the number of atoms and kind of atoms present in the molecule is 45 and 3 respectively.

(c)

Interpretation Introduction

Interpretation: The number and kinds of atoms present in trinitrotoluene (TNT) need to be determined.

Concept Introduction: Molecular formula tells about the total number of atoms of the element present in the molecule of a substance. It confirms the type of atoms as well the number of atoms of the same type present in the molecule. For example, the molecular formula of water is ${\text{H}}_{\text{2}}\text{O}$ ; thus, it can be seen that 1 water molecule contains 2 hydrogen atoms and 1 oxygen atom.

Explanation of Solution

The given compound is trinitrotoluene with the molecular formula ${\text{C}}_7{\text{H}}_5{\text{N}}_3{\text{O}}_{\text{6}}$ . From the molecular formula of the compound, it is clear that there are four kinds of atoms present in the compound that is carbon, hydrogen, nitrogen, and oxygen. Also, there are 7 carbon atoms, 5 hydrogen atoms, and 3 nitrogen atoms, and 6 oxygen atoms; thus, the total number of atoms in the compound will be $7+5+3+6=21$ .

Thus, the number of atoms and kind of atoms present in the molecule is 21 and 4 respectively.