Problem 54 - Chemistry The Molecular Science

Question

Write the molecular formula for each substance. (a) The hydrocarbon heptane, which has seven carbon atoms and 16 hydrogen atoms (b) Acrylonitrile (the basis of Orlon and Acrilan fibers), which has three carbon atoms, three hydrogen atoms, and one nitrogen atom

Step-by-Step Solution

Answer

(a) \(C_7H_{16}\); (b) \(C_3H_3N\).

Step 1: Identify Elements in Heptane

Heptane is a hydrocarbon, which means it consists only of carbon (C) and hydrogen (H) atoms. According to the problem, it has seven carbon atoms and sixteen hydrogen atoms.

Step 2: Write Molecular Formula for Heptane

To write the molecular formula for heptane, use the number of each type of atom present. Represent carbon with the symbol 'C' and hydrogen with 'H'. So, heptane's molecular formula is written as \( C_7H_{16} \).

Step 3: Identify Elements in Acrylonitrile

Acrylonitrile contains carbon, hydrogen, and nitrogen atoms. From the problem, we know it consists of three carbon atoms, three hydrogen atoms, and one nitrogen atom.

Step 4: Write Molecular Formula for Acrylonitrile

For acrylonitrile, use the given number of each type of atom to determine the molecular formula. Write it as \( C_3H_3N \) where 'C' stands for carbon, 'H' for hydrogen, and 'N' for nitrogen.

Key Concepts

Heptane Formula

Heptane is a member of the hydrocarbons family, which are compounds made entirely of hydrogen and carbon. In chemistry, hydrocarbons are often simplified into molecular formulas that tell us the exact number of each type of atom present. It helps chemists understand what the substance is made of, and how it might react with other chemicals.
Heptane specifically has seven carbon atoms and sixteen hydrogen atoms, making its molecular formula simple but informative:

• Carbon is symbolized with a 'C'.
• Hydrogen is symbolized with an 'H'.

Thus, we write the molecular formula of heptane as \(C_7H_{16}\). This means for every molecule of heptane, there are seven carbon atoms and sixteen hydrogen atoms.
Molecular formulas like \(C_7H_{16}\) are a vital tool for chemists, allowing them to quickly convey complex information about the structure of a molecule in a compact form.

Acrylonitrile Formula

Acrylonitrile is a colorful and versatile chemical fundamental in the manufacturing of synthetic fibers like Orlon and Acrilan. At the molecular level, acrylonitrile contains carbon, hydrogen, and nitrogen atoms, which contribute to both its properties and uses.
To determine the molecular formula for acrylonitrile, you must account for these elements:

• Carbon, denoted by 'C'. In acrylonitrile, there are three carbon atoms.
• Hydrogen, represented by 'H'. Acrylonitrile includes three hydrogen atoms.
• Nitrogen, which is indicated by 'N'. This compound has one nitrogen atom.

Therefore, the molecular formula of acrylonitrile is noted as \(C_3H_3N\), encapsulating the count of each type of atom present in the compound.
This not only helps in identifying the composition but also aids in predicting reactions and behaviors in various chemical processes.

Chemical Symbols

Chemical symbols are simplified notations typically consisting of one or two letters used to represent a chemical element in scientific contexts. These symbols are foundational in conveying the intricate language of chemistry.
Each chemical symbol is standardized and universally recognized, allowing chemists worldwide to communicate effectively about chemicals and their interactions. For instance:

• 'C' is the chemical symbol for carbon. When you see this in a formula, it denotes the presence of carbon atoms.
• 'H' represents hydrogen. Knowing this helps interpret its chemical role and bonds in formulas like \(H_2O\) or hydrocarbons such as \(C_7H_{16}\).
• 'N' stands for nitrogen, crucial for understanding compounds in biochemistry or industrial chemistry.

These symbols are part of a broader system called the periodic table of elements. Learning these symbols is essential for studying any aspects of chemistry, as they simplify and standardize complex scientific information.
Using chemical symbols can seem daunting at first, but with practice, they make understanding and writing chemical formulas much easier.