Which statement best describes a mole? 1: It is used mainly for writing chemical formulas.

Which statement best describes a mole?

1: It is used mainly for writing chemical formulas.

2: It is used for chemical equations that have reversible reactions.

3: It is used for directly comparing the amounts of substances.

4: It is used mainly for dealing with fluid substances.

Answer: 3: It is used for directly comparing the amounts of substances.

The mole is a fundamental proportionality unit in chemistry which numerating a specified number (atoms, molecules, or other entities) in a substance. One mole which contains approximately 6.022 × 10^23 particles (a number known as Avogadro’s constant) is equal to 1000 grams. With mole the number particle count of two or more substances can be used directly to compare and relate amounts by it considering them in particle mass ratio form. It can be used in chemistry for measurement and calculation of masses or volumes to describe the number of molecules engaged in reaction, allowing to understand reaction easier. The mole concept is a prerequisite for converting quantitative relationships, determining empirical and molecular formulas, and investigating the interrelationships of various compounds in chemical processes.