Chapter U1.25, Problem 1TAI

Interpretation Introduction

Interpretation:

Sorting of substances into general categories is to be explained.

Concept introduction:

There are millions of substances in the environment around us. It is very difficult to identify all these substances. Therefore, it is important to arrange substances into general categories by considering two properties: solubility and conductivity.

Answer to Problem 1TAI

Most of the substances around us can be grouped into different categories based on two properties:

1. Solubility - Solubility is a general property by which one can sort substances into two categories: soluble and insoluble.
2. Conductivity of electricity - Conductivity is a general property by which one can sort substances into two categories: conductors and non - conductors.

Explanation of Solution

Two major properties of substances based on which they can be sorted into various categories are:

1. Solubility: Solubility is a general property by which one can sort substances into two categories: soluble and insoluble. Those which can dissolve in water and form aqueous solution are called soluble and those which do not dissolve in water are called insoluble.

For example: sugar is soluble in water but sand is insoluble in water. Some gases and liquids are also soluble in water.

2. Conductivity of electricity -Some substances can allow flow of electricity through them. Such substances are called conductors. For example - copper.

Some substances do not allow flow of electricity through them. Such substances are called non - conductors. For example: plastic.

Therefore, there are four categories of substances:

1. Those which dissolves and conducts - for example salt, calcium chloride, etc.
2. Those which do not dissolve and conducts - for example: gold, copper, etc.
3. Those which dissolves and do not conduct - for example: sugar, ethanol, etc.
4. Those which do not dissolve and do not conduct - for example: sand, paraffin, etc.

Conclusion

Substancescan be sorted into one of the four categories based on whether they dissolve in water and conduct electricity. These two properties are directly related to the intermolecular forces of attraction between the molecules.