Problem 93 - Chemistry Matter and Change

Question

Name each molecule. $$\begin{array}{ll}{\text { a. } \mathrm{NF}_{3}} & {\text { c. } \mathrm{SO}_{3}} \\ {\text { b. } \mathrm{NO}} & {\text { d. } \mathrm{SiF}_{4}}\end{array}$$

Step-by-Step Solution

Answer

a. Nitrogen trifluoride, b. Nitrogen monoxide, c. Sulfur trioxide, d. Silicon tetrafluoride.

Step 1: Identify the Name of NF3

The molecule \( \text{NF}_3 \) consists of nitrogen (N) and fluorine (F) atoms. In naming binary molecular compounds like this, we use prefixes to indicate the number of each type of atom. Here, 'tri-' is used for three fluorine atoms. Therefore, the name is nitrogen trifluoride.

Step 2: Identify the Name of NO

The molecule \( \text{NO} \) consists of nitrogen (N) and oxygen (O). In this case, the prefix 'mono-' is used for one oxygen atom, although it's often omitted for the first element. Hence, the name is nitrogen monoxide.

Step 3: Identify the Name of SO3

The molecule \( \text{SO}_3 \) has sulfur (S) and three oxygen (O) atoms. The prefix 'tri-' is used for three oxygen atoms. Therefore, the name of \( \text{SO}_3 \) is sulfur trioxide.

Step 4: Identify the Name of SiF4

The molecule \( \text{SiF}_4 \) consists of silicon (Si) and four fluorine (F) atoms. We use the prefix 'tetra-' for four fluorine atoms. Thus, the name is silicon tetrafluoride.

Key Concepts

Binary Molecular Compounds

Binary molecular compounds consist of two different non-metal elements. These compounds are quite common in chemistry, especially in organic and inorganic chemistry. When naming binary molecular compounds, the goal is to clearly communicate the exact composition of the compound. For example:

• NF₃ is named as nitrogen trifluoride, with 'nitrogen' representing the first element (N) and 'trifluoride' indicating three fluorine (F) atoms.
• SiF₄ is silicon tetrafluoride. This compound includes silicon (Si) and four fluorine atoms, where 'tetra-' denotes four.

Binary molecular compounds follow a systematic approach to ensure each molecule's formula can be correctly inferred from its name. This naming pattern helps chemists and students quickly recognize the elements and their quantities in compounds.

Prefixes in Chemistry

Prefixes are vital in the nomenclature of binary molecular compounds because they tell us how many atoms of each element are present in a molecule. Knowing these prefixes is essential for naming compounds correctly. Here's a quick guide to the most common prefixes:

• Mono- for 1 (often omitted for the first element)
• Di- for 2
• Tri- for 3
• Tetra- for 4
• Penta- for 5

For example, in the compound SO₃ (sulfur trioxide), the 'tri-' prefix indicates the presence of three oxygen atoms.
Understanding these prefixes helps in constructing and deciphering compound names, making the process of learning chemistry more seamless.

Molecular Formulas

Molecular formulas provide a concise way of expressing the composition of a compound using the symbols of its constituent elements and numerical subscripts. Each symbol in the formula represents a specific element, while the numbers indicate the number of atoms of each element present. For example:

• NO stands for nitrogen monoxide, indicating one nitrogen (N) and one oxygen (O) atom. Even though 'mono-' is rarely used for the first element, it can denote single atoms in general naming conventions.
• SO₃ signifies sulfur (S) combined with three oxygen (O) atoms, forming sulfur trioxide.

Molecular formulas offer a universal language for scientists around the world, allowing them to comprehend and communicate complex chemical compounds clearly and effectively. By understanding molecular formulas, students can better grasp the relationships and ratios of atoms within molecules.