Question

Chloropropane is a compound derived from propane by substituting $\mathrm{Cl}$ for $\mathrm{H}$ on one of the carbon atoms. (a) Draw the structural formulas for the two isomers of chloropropane. (b) Suggest names for these two compounds.

Short answer

The two isomers of chloropropane are: (a) 1-chloropropane with structural formula: Cl H H | | | C-C-C H H H (b) 2-chloropropane with structural formula: H H H | | | C-C-C | | | H Cl H Their names, according to the IUPAC nomenclature, are 1-chloropropane and 2-chloropropane.

Step-by-step solution

Draw the structural formula of propane

Propane is an alkane with three carbon atoms and eight hydrogen atoms. Its molecular formula is ${\mathrm{C}}_3{\mathrm{H}}_8$. The structural formula of propane is: H H H | | | C-C-C | | | H H H

Replace one hydrogen atom with chlorine

We will substitute one hydrogen atom with chlorine to create a chloropropane isomer. The possible positions for chlorine are on a carbon atom at one of the ends, or on the middle carbon atom.

Draw the structural formulas of chloropropane isomers

There are two possible isomers for chloropropane, depending on the position of the chlorine atom. They are as follows: 1-chloropropane: Cl H H | | | C-C-C H H H 2-chloropropane: H H H | | | C-C-C | | | H Cl H

Name the isomers of chloropropane according to the IUPAC nomenclature

The names of the isomers of chloropropane are determined based on the position of the chlorine atom: (a) The structural formula of 1-chloropropane is: Cl H H | | | C-C-C H H H (b) The structural formula of 2-chloropropane is: H H H | | | C-C-C | | | H Cl H These two compounds are named as 1-chloropropane and 2-chloropropane according to the IUPAC nomenclature.

Key concepts

Structural Formulas

Understanding the structure of organic molecules is crucial to grasp how they function and react. Structural formulas provide a way to visualize the atomic composition and the connections between atoms in a molecule. In the context of chloropropane isomers, the structural formula allows us to see the specific arrangement of carbon (C), hydrogen (H), and chlorine (Cl) atoms.

By depicting the bonds between the atoms, structural formulas like those for chloropropane isomers reveal the difference between the 1-chloropropane and 2-chloropropane. While both compounds have the same types and numbers of atoms, their structural differences impart unique chemical properties to each isomer.

With 1-chloropropane, the Cl atom is bonded to the first carbon in the chain, whereas in 2-chloropropane, the Cl atom is bonded to the central carbon. The visualization of these positions is essential for understanding reactions and properties related to chloropropane.

IUPAC Nomenclature

The International Union of Pure and Applied Chemistry (IUPAC) nomenclature system provides a standardized way to name chemical compounds. For chloropropane isomers, this system allows us to assign unambiguous names that reflect the structure of each molecule.

The IUPAC name is based on finding the longest continuous chain of carbon atoms, identifying the various substituents, and assigning a number to the carbon atom which the substituent is attached to in order to minimize the numbers in the name. The prefix 'chloro-' indicates the presence of a chlorine atom, and the 'propane' part of the name reflects the three-carbon alkane structure.

Therefore, 1-chloropropane has its chlorine on the first carbon atom, while 2-chloropropane has its chlorine on the second carbon atom. Understanding this naming system is vital not only for clear communication but also as a first step in deducing the shape and properties of the molecule.

Alkane Derivatives

Alkanes are simple organic compounds that consist entirely of single-bonded carbon and hydrogen atoms, and they serve as the backbone for a variety of derivatives, one of which is chloropropane. Derivatives are formed when one or more hydrogen atoms in the alkane are replaced by other atoms or groups of atoms.

In the case of chloropropane, a hydrogen atom is replaced by a chlorine atom. This small change creates compounds with different physical and chemical properties. There are two possible derivatives of chloropropane due to the different positions the chlorine atom can occupy on the propane chain. These variations are known as isomers, which have the same molecular formula but different structural formulas.

Exploring alkane derivatives like chloropropane showcases the diversity possible within organic chemistry, as a single change in structure can lead to a new compound with its unique set of characteristics.

Organic Chemistry

Organic chemistry is the branch of chemistry that studies carbon-containing compounds. This vast field covers a wide variety of substances, from simple alkanes to complex molecules found in biological systems. Organic molecules, such as chloropropane, often have numerous isomers, which demonstrate the intricate nature of chemical structures.

In organic chemistry, understanding isomers is essential for predicting how a compound will behave in different situations. The chloropropane isomers, for example, may react differently with other reagents or under different conditions primarily due to the position of the chlorine atom.

The principles of organic chemistry also lay the foundation for recognizing the significance of the structural formulas, IUPAC nomenclature, and derivatives. Mastery of these concepts allows chemists to not only name and visualize compounds but also to synthesize new substances and understand their potential applications.