Question

Provide the formula for each of the following binary molecular compounds: (a) dinitrogen pentaoxide (b) carbon tetrachloride (c) iodine monobromide (d) dihydrogen sulfide

Short answer

(a) \( \text{N}_2\text{O}_5 \), (b) \( \text{CCl}_4 \), (c) \( \text{IBr} \), (d) \( \text{H}_2\text{S} \)

Step-by-step solution

Identifying Elements and Prefixes

For each compound, identify the elements and the Greek prefixes that indicate the number of atoms present. For example, for 'dinitrogen pentaoxide', the prefix 'di-' means two, indicating the presence of two nitrogen atoms, and 'penta-' means five, indicating five oxygen atoms.

Writing the Chemical Formula for Dinitrogen Pentaoxide

The compound is 'dinitrogen pentaoxide'. 'Di-' indicates two nitrogen atoms (N) and 'penta-' indicates five oxygen atoms (O). Therefore, the formula is \( \text{N}_2\text{O}_5 \).

Writing the Chemical Formula for Carbon Tetrachloride

The compound is 'carbon tetrachloride'. There is one carbon atom (C) and the prefix 'tetra-' indicates four chlorine atoms (Cl). Therefore, the formula is \( \text{CCl}_4 \).

Writing the Chemical Formula for Iodine Monobromide

The compound is 'iodine monobromide'. 'Mono-' typically indicates one but is often omitted for the first element. Thus, there is one iodine atom (I) and one bromine atom (Br). Therefore, the formula is \( \text{IBr} \).

Writing the Chemical Formula for Dihydrogen Sulfide

The compound is 'dihydrogen sulfide'. 'Di-' indicates two hydrogen atoms (H) and there is one sulfur atom (S). Therefore, the formula is \( \text{H}_2\text{S} \).

Key concepts

Binary Molecular Compounds

Binary molecular compounds are formed when two nonmetals share electrons to form a molecule. These compounds are characterized by their simple structure, having just two different elements. This type of molecule can be used to describe many of the common chemicals we encounter both in academics and daily life. The understanding of binary molecular compounds helps in predicting the chemical behavior and reactivity of these substances.

To accurately express these compounds, it's essential to determine the constituents and their respective number of atoms. Combining the elements together in their simplest whole-number ratios, using Greek prefixes, provides the exact stoichiometry.

• Examples include well-known chemicals such as water ( H_2O ) and carbon dioxide ( CO_2 ).
• Binary molecular compounds differ from ionic compounds, as they involve covalent rather than ionic bonding.

Understanding binary molecular compounds is crucial for mastering more complex chemical concepts. Once you grasp how these compounds are named and structured, it's easier to delve into other areas of chemistry, such as reactions and thermodynamics.

Greek Prefixes

Greek prefixes are an essential part of the chemical nomenclature for naming binary molecular compounds. They help indicate the number of atoms of each element present in the compound. For instance, the prefix 'di-' reflects the presence of two atoms, while 'tri-' indicates three. These numerical prefixes streamline communication in chemistry by providing precision regarding molecular composition.

Here's a quick reference for some common Greek prefixes:

• Mono-: 1
• Di-: 2
• Tri-: 3
• Tetra-: 4
• Penta-: 5
• Hexa-: 6
• Hepta-: 7
• Octa-: 8
• Nona-: 9
• Deca-: 10

It is important to note that the prefix "mono-" is often omitted in naming the first element. For example, in carbon monoxide ( CO ), the prefix "mono-" is absent for carbon but used for oxygen. These prefixes aid students and chemists in ensuring accurate and consistent descriptions of molecular substances.

Chemical Nomenclature

Chemical nomenclature is the systematic approach used in naming chemical substances. It's like a universal language for chemists, allowing clear and standardized communication across language barriers. For binary molecular compounds, the focus is on the order of naming: start with the element that appears first in the formula. The second element’s name is changed to an "-ide" ending.

Let's break down the rules with an example for clarity:

• The first element in the formula retails its name. For instance, in carbon tetrachloride ( CCl_4 ), "carbon" is the first element.
• The second element's name is modified to end in "-ide." In carbon tetrachloride, "chlorine" becomes "chloride."
• Use Greek prefixes to denote the number of each type of atom present. Remember, omit "mono-" for the first element.

Adhering to these naming rules helps in easily identifying the structure and formula of a compound just by its name. The consistency provided by chemical nomenclature is invaluable in scientific research, education, and industry, ensuring that when a compound is referenced, all parties understand exactly which substance is being discussed.