Problem 78 - Chemistry The Central Science In Si Units

Question

The oxides of nitrogen are very important components in urban air pollution. Name each of the following compounds: (d) \(\mathrm{N}_{2} \mathrm{O}_{5},\), (a) \(\mathrm{N}_{2} \mathrm{O}\), (b) NO, (c) \(\mathrm{NO}_{2}\), \((\mathbf{e}) \mathrm{N}_{2} \mathrm{O}_{4}\).

Step-by-Step Solution

Answer

(d) Dinitrogen pentoxide, (a) Dinitrogen monoxide, (b) Nitrogen monoxide, (c) Nitrogen dioxide, (e) Dinitrogen tetroxide.

Step 1: Understanding Nomenclature Basics

For binary compounds involving non-metals, such as nitrogen oxides, we use prefixes to indicate the number of atoms of each element. The prefixes are: mono- (1), di- (2), tri- (3), tetra- (4), penta- (5), hexa- (6), and so on. These are combined with the element names.

Step 2: Naming Compound (a) \(\mathrm{N_2O}\)

The compound \(\mathrm{N_2O}\) has two nitrogen atoms and one oxygen atom. According to the naming system, it is named as dinitrogen monoxide. Although 'mono-' is typically omitted for the first element, it is included for oxygen.

Step 3: Naming Compound (b) NO

The compound NO consists of one nitrogen atom and one oxygen atom. Its name is nitrogen monoxide. In this particular case, the mono- is also applied for the first element since it is a common exception.

Step 4: Naming Compound (c) \(\mathrm{NO_2}\)

For \(\mathrm{NO_2}\), there is one nitrogen atom and two oxygen atoms. This compound is named as nitrogen dioxide, using 'di-' to indicate the two oxygen atoms.

Step 5: Naming Compound (d) \(\mathrm{N_2O_5}\)

In the compound \(\mathrm{N_2O_5}\), there are two nitrogen atoms and five oxygen atoms. The name for this compound is dinitrogen pentoxide, using the prefixes di- for nitrogen and penta- for oxygen.

Step 6: Naming Compound (e) \(\mathrm{N_2O_4}\)

The compound \(\mathrm{N_2O_4}\) contains two nitrogen atoms and four oxygen atoms. Its name is dinitrogen tetroxide, with di- for nitrogen and tetra- for oxygen.

Key Concepts

Nitrogen Oxides

Nitrogen oxides are a group of chemical compounds that include different combinations of nitrogen and oxygen. These compounds are significant when it comes to atmospheric chemistry and urban pollution. Some of the key nitrogen oxides include:

• Nitrous oxide (\(\mathrm{N_2O}\): Also known as "laughing gas," used as an anesthetic and a greenhouse gas.
• Nitric oxide (NO): A colorless gas that plays a role in the human body, but also contributes to air pollution when emitted from vehicle engines.
• Nitrogen dioxide (\(\mathrm{NO_2}\): A reddish-brown gas, known for its role in creating smog and acid rain.
• Dinitrogen tetroxide (\(\mathrm{N_2O_4}\): Often used in rocket propellants, exists in equilibrium with nitrogen dioxide in the atmosphere.
• Dinitrogen pentoxide (\(\mathrm{N_2O_5}\): Important for the formation of nitric acid, acts as an oxidizer.

These compounds usually result from combustion processes, like those found in car engines or power plants. Understanding their chemical behavior and environmental impact helps regulate air quality.

Molecular Compounds

Molecular compounds are substances formed by the combination of nonmetals through covalent bonds. In these compounds, the atoms share electrons to attain stability. This sharing makes these compounds distinct from ionic compounds, where electrons are transferred.

An important aspect of molecular compounds is how their names reflect their composition. By using systematic naming conventions, scientists and students can deduce the type and number of atoms in a compound. For example:

• Dinitrogen monoxide (\(\mathrm{N_2O}\): Consists of two nitrogen atoms and one oxygen atom.
• Nitrogen monoxide (NO): Has one nitrogen atom and one oxygen atom.

Recognizing molecular compounds is crucial, as it helps understand their chemical reactivity, properties, and interactions with other compounds. Mastery of these concepts enables a better grasp of complex chemical equations and reactions.

Prefixes in Chemistry

In the realm of chemistry, prefixes are essential for accurately naming chemical compounds, especially molecular ones. These prefixes provide clear information about the quantity of each type of atom present in a compound.

Common prefixes used include:

• Mono- (1): Typically omitted for the first element but used for the second, such as in nitrogen monoxide (NO).
• Di- (2): Used when there are two atoms. E.g., dinitrogen tetroxide (\(\mathrm{N_2O_4}\)).
• Tri- (3): Indicates three atoms.
• Tetra- (4): Signifies four atoms, used in names like dinitrogen tetroxide.
• Penta- (5): Indicates five atoms, such as in dinitrogen pentoxide (\(\mathrm{N_2O_5}\)).

These prefixes not only help in constructing chemical names but also aid in understanding the chemical formula and overall composition of molecular compounds. They are a fundamental part of chemical nomenclature and a key tool in the systematic naming of chemical substances.