Chapter 2, Problem 74A

(a)

Interpretation Introduction

Interpretation: The similarity and differences between copper and silver need to be explained.

Concept Introduction: The properties of elements depend on their position in the periodic table. Substances with the same physical properties can have different chemical properties. The physical and chemical properties of substances can be compared to explain the similarities and differences between them.

Explanation of Solution

Copper and silver both are metallic elements and belong to group 11 in the periodic table. Due to the same group number, they have similar physical and chemical properties. Both copper and silver are good conductors of heat and electricity. They have high melting and boiling points thus; they are used in making jewelry and coins. Both copper and silver are naturally occurring elements.

The difference is that silver is costly as compared to copper and silver is sparkly gray on the other hand, copper has a reddish-brown color.

(b)

Interpretation Introduction

Interpretation: The similarity and difference between distilled water and salt water need to be explained.

Concept Introduction: The properties of elements depend on their position in the periodic table. The substances with the same physical properties can have different chemical properties. The physical and chemical properties of substances can be compared to explain the similarities and differences between them.

Explanation of Solution

Distilled water and salt water are liquid in the state. They have similar physical properties like boiling and melting points. There is only a slight difference as the boiling point increases on dissolving salt in water.

Distilled water is free from ions and is considered a pure substance. On the other hand, saltwater contains ions. It is generally sodium chloride dissolved in water thus, it contains ${\mathrm{Na}}^{+}$

  ${\text{Cl}}^{+}$ ions. As there are no ions in the distilled water, it doesn’t conduct electricity, but salt water can conduct electricity due to the presence of sodium and chloride ions.

(c)

Interpretation Introduction

Interpretation: The similarity and differences between table sugar and table salt need to be explained.

Concept Introduction: The properties of elements depend on their position in the periodic table. Substances with the same physical properties can have different chemical properties. The physical and chemical properties of substances can be compared to explain the similarities and differences between them.

Explanation of Solution

Both table sugar and table salt are soluble in water. They both are white and crystalline solids.

Table sugar and table salt have different chemical natures. Here, table sugar is sucrose which is made up of carbon, hydrogen, and an oxygen atom. The chemical formula is ${\text{C}}_{\text{12}}{\text{H}}_{\text{22}}{\text{O}}_{\text{11}}$ . Table salt is composed of sodium and chloride ions with the molecular formula $\text{NaCl}$ . Table sugar has covalent bonds between the atoms and table sugar has ionic bonds. The boiling point of table salt $\left(801{}^{\text{o}}\text{C}\right)$ is higher than table sugar $\left({\text{186 }}^{\text{o}}\text{C}\right)$ .