Question

Give the name or chemical formula, as appropriate, for each of the following binary molecular substances: (a) \(\mathrm{SF}_{6},\) (b) \(\mathrm{IF}_{5}\), (c) \(\mathrm{XeO}_{3},\) (d) dinitrogen tetroxide, (e) hydrogen cyanide, (f) tetraphosphorus hexasulfide.

Short answer

(a) Sulfur hexafluoride (b) Iodine pentafluoride (c) Xenon trioxide (d) \(\mathrm{N}_{2}\mathrm{O}_{4}\) (e) \(\mathrm{HCN}\) (f) \(\mathrm{P}_{4}\mathrm{S}_{6}\)

Step-by-step solution

(a) Name of \(\mathrm{SF}_{6}\)

To find the name of \(\mathrm{SF}_{6}\), we see that there is one Sulfur atom and six Fluorine atoms. The prefix for six is "hexa-", so the compound's name is Sulfur hexafluoride.

(b) Name of \(\mathrm{IF}_{5}\)

For \(\mathrm{IF}_{5}\), we see that there is one Iodine atom and five Fluorine atoms. The prefix for five is "penta-", so the compound's name is Iodine pentafluoride.

(c) Name of \(\mathrm{XeO}_{3}\)

For \(\mathrm{XeO}_{3}\), there is one Xenon atom and three Oxygen atoms. The prefix for three is "tri-", so the compound's name is Xenon trioxide.

(d) Chemical formula of dinitrogen tetroxide

For dinitrogen tetroxide, the prefixes "di-" and "tetra-" correspond to two and four, respectively. The name contains two elements, Nitrogen and Oxygen. Therefore, dinitrogen tetroxide has a chemical formula of \(\mathrm{N}_{2}\mathrm{O}_{4}\).

(e) Chemical formula of hydrogen cyanide

Hydrogen cyanide contains two elements, hydrogen and cyanide ion (CN). There is only one hydrogen atom present, which is implied because no prefix is given. Hence, the chemical formula for hydrogen cyanide is \(\mathrm{HCN}\).

(f) Chemical formula of tetraphosphorus hexasulfide

In tetraphosphorus hexasulfide, the prefixes "tetra-" and "hexa-" correspond to four and six, respectively. This compound contains two elements, Phosphorus and Sulfur. Hence, the chemical formula for tetraphosphorus hexasulfide is \(\mathrm{P}_{4}\mathrm{S}_{6}\). In conclusion, the names or chemical formulas for the given binary molecular substances are as follows: (a) Sulfur hexafluoride (b) Iodine pentafluoride (c) Xenon trioxide (d) \(\mathrm{N}_{2}\mathrm{O}_{4}\) (e) \(\mathrm{HCN}\) (f) \(\mathrm{P}_{4}\mathrm{S}_{6}\)

Key concepts

Chemical Nomenclature

Understanding chemical nomenclature is essential for identifying and communicating about different compounds in chemistry. It is a systematic method for naming chemical compounds and provides clarity across scientific and educational fields.

When dealing with binary molecular compounds, where two nonmetallic elements combine, specific rules apply. Traditionally, the element with a more positive electrical nature (closer to the left and bottom of the periodic table) is named first, using its elemental name. If the second element is in its pure elemental form, it’s named with the suffix '-ide.' Therefore, for compound \textbf{SF}\(_{6}\), we name it as Sulfur hexafluoride, indicating the presence of Sulfur and Fluorine.

For proper nomenclature form, no prefix is used for the first element if there's only one atom of it in the molecule. These rules help maintain consistency and allow scientists to deduce the constituent elements of a molecule simply by its name.

Prefixes in Chemical Compounds

Binary molecular compounds often use prefixes to denote the number of atoms present in the compound. These prefixes are derived from Greek or Latin numbers and are critical for accurate identification. Here is a list of common prefixes:

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

For example, \textbf{IF}\(_{5}\) is named Iodine pentafluoride, highlighting the presence of one Iodine and five Fluorine atoms in the compound. In cases where only one atom of the first element is present, such as in \textbf{HCN}, the 'mono-' prefix is generally omitted, and the compound is simply called Hydrogen cyanide.

Chemical Formulas

The chemical formula of a substance offers a quick representation of its molecular composition, using symbols for each element and subscripts to show the number of atoms. The chemical formula provides immediate insight into the molecule's makeup.

For example, the name dinitrogen tetroxide translates into the formula \textbf{N}\(_{2}\)\textbf{O}\(_{4}\), signaling the compound is composed of two nitrogen atoms (di-) and four oxygen atoms (tetra-). As a language of chemistry, these formulas serve as a universal shorthand, allowing chemists to communicate complex structures succinctly and accurately.

To write the chemical formula correctly, it's essential to understand the type of compound you're dealing with, as ionic compounds will have different naming conventions compared to molecular compounds like the ones we are focusing on. Remember that correctly interpreting chemical formulas is not just helpful for academic exercises; it is also fundamental for practical laboratory work and commercial applications where precise measurements and understanding of substances are crucial.