Question

Antifreeze Research ethylene glycol, an antifreeze- coolant, to learn its chemical formula. Draw its Lewis structure and identify the sigma and pi bonds.

Short answer

The chemical formula of ethylene glycol is C2H6O2. Its Lewis structure can be represented as: H | H - C - O - H | C - O - H | H In this molecule, there are 9 sigma bonds: 1 C-C, 2 C-O, 4 C-H, and 2 O-H bonds. There are no pi bonds in the ethylene glycol molecule.

Step-by-step solution

Determine the chemical formula of ethylene glycol

Ethylene glycol is an organic compound with the chemical formula C2H6O2. It consists of two carbon atoms, six hydrogen atoms, and two oxygen atoms.

Construct a skeleton structure

To draw the Lewis structure, we first need to construct a skeleton structure of ethylene glycol. In ethylene glycol, the two carbon atoms form a single bond with each other, and each carbon atom is bonded to one oxygen atom and two hydrogen atoms. The skeleton structure can be represented as follows: C - C | | O O | | H H H H

Draw the Lewis structure

Now, we will add the electron pairs around the atoms to complete the Lewis structure. Each carbon atom needs four bonds, each oxygen atom needs two bonds, and each hydrogen atom needs one bond. The complete Lewis structure is as follows: H | H - C - O - H | C - O - H | H

Identify sigma and pi bonds

In the ethylene glycol molecule, all the bonds are single covalent bonds. In single bonds, there is only one sigma bond and no pi bond. Sigma bonds: 1. C-C: 1 sigma bond 2. C-O: 2 sigma bonds (one for each C-O bond) 3. C-H: 4 sigma bonds (two for each carbon) 4. O-H: 2 sigma bonds (one for each O-H bond) There are no pi bonds in the ethylene glycol molecule. In conclusion, the ethylene glycol molecule has a Lewis structure with 9 sigma bonds and 0 pi bonds.

Key concepts

Lewis structure

A Lewis structure is a simple yet powerful way to represent molecules and visualize the connections between atoms. For ethylene glycol, which has the chemical formula C\(_2\)H\(_6\)O\(_2\), it helps to lay out how atoms are bonded. The Lewis structure includes symbols for each atom and dots representing valence electrons, giving insight into possible chemical bonds.

Here’s how it works for ethylene glycol:

• Each carbon (C) seeks four bonds for stability, filling up its valence shell.
• Oxygen (O) generally wants two bonds.
• Hydrogen (H) only needs one bond to achieve a full outer shell.

The structure follows the 'octet rule,' helping us see how electrons are shared or bonded between atoms. In ethylene glycol, carbon shares electrons not just with oxygen but also hydrogen, showing all single bonds between these atoms. This is crucial for understanding its molecular stability and reactions in organic chemistry contexts.

chemical bonds

Chemical bonds are the links that hold atoms together within molecules. Let's delve into their role in ethylene glycol. The bonds in ethylene glycol are primarily covalent. Covalent bonds form when two atoms share electrons to achieve more stable electron configurations.

Ethylene glycol is made up of:

• C-C bond: Two carbon atoms sharing electrons.
• C-O bonds: Carbon atoms somewhat unequally sharing electrons with oxygen due to oxygen’s higher electronegativity.
• C-H bonds: Carbon shares electrons with less electronegative hydrogen atoms.
• O-H bonds: Each oxygen shares electrons with hydrogen.

These shared electron pairs are what give ethylene glycol its chemical stability and properties as a coolant. Recognizing these bonds is essential for understanding molecular interactions in chemistry, making ethylene glycol a key example of how covalent bonds function in everyday compounds.

sigma bonds

When discussing ethylene glycol's bonding, it's important to understand the concept of sigma bonds. Sigma bonds (σ bonds) are the strongest type of covalent chemical bonds, formed by the overlapping of atomic orbitals directly between the bonding atoms.

In ethylene glycol:

• The C-C bond is a sigma bond, formed by the head-on overlapping of carbon’s atomic orbitals.
• Each C-O bond is a sigma bond, with the carbon and oxygen atoms overlapping directly.
• Similarly, the C-H bonds in ethylene glycol are sigma bonds.
• O-H bonds are also sigma bonds, with the overlapping of oxygen and hydrogen’s orbitals.

All these contributions result in nine sigma bonds in ethylene glycol, indicative of its structural stability. Understanding these fundamental sigma bonds allows us to predict the molecule's physical properties and reactivity, emphasizing their significance in organic chemistry.

organic chemistry

Organic chemistry is the branch of chemistry dealing with carbon-based molecules, like ethylene glycol. This field examines the structure, properties, reactions, and synthesis of organic compounds. Ethylene glycol, as an organic molecule, highlights the typical features of organic structures.

Characteristics of ethylene glycol in organic chemistry include:

• Presence of carbon atoms arranged in a chain or ring.
• Involvement of functional groups, like the hydroxyl (OH) group, which influences the molecule's chemical behavior.
• Ability to undergo numerous reactions, including oxidation and esterification, making it versatile in applications.

Understanding ethylene glycol's properties from an organic chemistry standpoint allows chemists to harness its properties in a range of applications, from being used as antifreeze to its role in manufacturing and industrial processes. This showcases how organic chemistry is essential for creating useful materials in our daily lives.