Question

How many atoms are specified by each of these prefixes: mono-, di-, tri-, tetra-, penta-,hexa-?

Short answer

The prefixes specify the following number of atoms: mono- (1), di- (2), tri- (3), tetra- (4), penta- (5), hexa- (6).

Step-by-step solution

Understanding Prefixes

In chemistry, prefixes are used to indicate the number of atoms of an element in a compound. Each prefix corresponds to a specific number.

Mono- Prefix

The prefix 'mono-' means one. Therefore, it specifies one atom.

Di- Prefix

The prefix 'di-' means two. It specifies two atoms.

Tri- Prefix

The prefix 'tri-' signifies three. It specifies three atoms.

Tetra- Prefix

The prefix 'tetra-' indicates four. It specifies four atoms.

Penta- Prefix

The prefix 'penta-' means five. It specifies five atoms.

Hexa- Prefix

The prefix 'hexa-' means six. It specifies six atoms.

Key concepts

Stoichiometry

Stoichiometry is a branch of chemistry that involves the calculation of reactants and products in chemical reactions. It is a quantitative relationship between the different molecules in a balanced chemical equation. For example, the reactants in a chemical reaction combine in a specific ratio to form products, and stoichiometry provides the tools to determine these proportions. This concept is pivotal when it comes to understanding how prefixes play a role in chemical reactions.

Consider a simple water molecule, H₂O, which indicates two hydrogen atoms ('di-' meaning two) for every one oxygen atom ('mono-' meaning one). In stoichiometric calculations, knowing the exact number of atoms present, as indicated by the prefixes, allows chemists to calculate the mass of reactants needed or predict the mass of products formed in a chemical reaction. It ensures that the law of conservation of mass is adhered to, with the mass of reactants equaling the mass of products.

Molecular Composition

Molecular composition refers to the number and type of atoms that make up a molecule. It is essential in determining the molecule's properties, including its chemical behavior and physical characteristics. Chemical prefixes directly inform us of molecular composition, by indicating the amount of each element in a compound.

For instance, carbon dioxide is composed of one carbon atom and two oxygen atoms. The prefix 'di-' in 'dioxide' implies the presence of two oxygen atoms. Knowledge of these prefixes becomes actionable when predicting the outcome of chemical reactions or synthesizing new compounds. A balanced equation respecting the molecular composition of the reactants must be maintained to ensure that the products formed are consistent with the laws of chemistry.

Chemical Nomenclature

Chemical nomenclature is the standardized system for naming chemical compounds. It relies heavily on a set of rules and conventions, including the use of Greek-derived prefixes to denote the number of atoms of each element in a molecule. This systematic approach allows chemists to communicate with precision and avoid confusion.

The prefixes 'mono-', 'di-', 'tri-', 'tetra-', 'penta-', and 'hexa-' each denote the numbers one through six, respectively. Understanding these prefixes is essential when learning chemical nomenclature, as they are frequently used to name inorganic compounds, especially those within coordination chemistry. For example, sulfur hexafluoride, which contains one sulfur atom and six fluorine atoms, gets its name from the prefix 'hexa-', indicating six. A well-grounded understanding of these prefixes facilitates the accurate naming of compounds and the clarity in scientific communication.