Problem 60 - Introductory Chemistry Atoms First

Question

Name the alkanes that do not use Greek prefixes in their names, and draw the structural formula for each.

Step-by-Step Solution

Answer

The alkanes that do not use Greek prefixes in their names are methane (CH₄), ethane (C₂H₆), propane (C₃H₈), and butane (C₄H₁₀). Their structural formulas are as follows: Methane: H | C | H Ethane: H H | | C--C | | H H Propane: H H H | | | H--C--C--C--H | | | H H H Butane: H H H H | | | | H--C--C--C--C--H | | | | H H H H

Step 1: State the basic alkanes without Greek prefixes

There are four basic alkanes that do not use Greek prefixes. Their names are derived directly from the number of carbon atoms present in each molecule. These are methane, ethane, propane and butane.

Step 2: Draw the structural formulas for methane, ethane, propane and butane

1. Methane (CH4): Methane has one carbon and four hydrogen atoms. The structural formula is simple: * * H * | * C * | * H 2. Ethane (C2H6): Ethane has two carbon and six hydrogen atoms. The structural formula for ethane is as follows: * * H H * | | * C--C * | | * H H * 3. Propane (C3H8): Propane has three carbon and eight hydrogen atoms. The structural formula for propane is: * * H H H * | | | * H--C--C--C--H * | | | * H H H * 4. Butane (C4H10): Butane has four carbon and ten hydrogen atoms. The structural formula for butane is: * * H H H H * | | | | * H--C--C--C--C--H * | | | | * H H H H * These are the four basic alkanes that do not use Greek prefixes in their names, and their respective structural formulas.

Key Concepts

Structural Formulas

Understanding structural formulas is crucial in chemistry to depict the arrangement of atoms in molecules. For alkanes, these diagrams show how carbon and hydrogen atoms are bonded.
Each line represents a bond between atoms. The simplest alkane, methane, uses a straightforward structure, while more complex alkanes like butane have longer chains.
Structural formulas help chemists visualize and predict the properties of the molecule. They are essential in identifying molecular variations and reactions. Drawing these structures requires knowing the number of atoms present and how they connect.

Methane

Methane is the simplest alkane and consists of one carbon atom bonded to four hydrogen atoms, denoted as CH₄.
In its structural formula, the carbon atom is surrounded symmetrically by hydrogen atoms, resembling a tetrahedral shape. This simple structure results in methane being a basic component of many organic compounds.
Methane is colorless, odorless, and is the main component of natural gas. It’s crucial in energy production and has significant environmental impacts as a greenhouse gas.

Ethane

Ethane is slightly more complex than methane, with the chemical formula C₂H₆. It consists of two carbon atoms connected by a single bond, each carbon being bonded to three hydrogen atoms.
This structure can be drawn by showing two carbon atoms side by side, with each carbon connected to three hydrogens.
Ethane is a colorless and odorless gas under standard conditions. It is used as a fuel and a building block for producing other chemicals like ethylene.
Understanding its structure helps in studying its reactivity and uses in industrial applications.

Propane

Propane, with the chemical formula C₃H₈, includes three carbon atoms forming a chain, connected to hydrogen atoms to fill each carbon's valency.
The central carbon atom in propane is bonded to two other carbons and two hydrogens, while the terminal carbons are each bonded to three hydrogens.
This formation can be drawn with three carbon atoms in sequence, ensuring all are fully bonded with hydrogen atoms.
Propane is widely known as a fuel source for heating and cooking, stored in liquid form under pressure in tanks.

Butane

Butane has the molecular formula C₄H₁₀, with four carbon atoms forming a straight chain or sometimes a branched chain.
The structural formula depicts four carbon atoms in a continuous line, with ten hydrogens attached to fulfill the carbon's valency.

• The unbranched version is known as "n-butane"
• A branched form is "isobutane"

Butane is commonly used in lighters and as a fuel in portable stoves.
Understanding the structural formula of butane is important for exploring its applications and behavior under different conditions.