Draw the skeletal structure and give the name and omega number of the following fatty acid: CH 3 CH 2 CH 2 CH 2 CH 2 HC=CHCH 2 HC=CHCH 2 CH 2 CH 2 CH 2 CH 2 CH 2 CH 2 COOH

Welcome back, everyone. Draw the skeletal structure for the following fatty acid, identify its name and determine its omega number. Note that all double bonds are in the cis configuration. So we have our structure and we want to convert it into the scalar structure. Let's begin from left to right. First of all, we have ch three followed by CH two and C. So the first double bond begins at carbon. Number three, we want to draw a total of three carbon atoms. So let's begin with the 1st 112 and three. And this is where the double bond starts. And since this is a cis configuration, we want to make sure that the LQ groups are on the same side of the double bond and the two implicit hygen are also on the same side of the double bond just above it, right? So we have our first fragment of the structure, a total of 12345 carbons. So now we have 45, right? And then we noticed that carbon number six, once again, it's going to have a double bond. So now we have carbon number six between carbon six and seven, we are going to draw a double bond followed by 89. So this is where we're going to get another double bond. So eight and nine, we're drawing another double bond in its cis configuration between nine and 10. Now we have 1112, 1314, 1516, 17, right? So essentially, let's look at how many carbons we have. 123456789, 1011, right? So we want to add carbon number 12, 13, 1415, 16, 17. And now carbon number 18 is with coo H. Now, what does that mean? Well, essentially, we have an asset. So we want to draw Kbox cell C. So Carbonel followed by o we have the required structure and now we simply want to identify its name. Let's notice that we have a form of 18 to 3, 18 carbons and three double bonds. And basically, this acid is called linoleic acid. What about the omega number? Well, whenever we consider the omega number, we have to identify which carbon gets the double bond first from left to right. Meaning we start with a carbon atom that is farthest from carboxy and that'll be the muscle group. And we simply want to enumerate the chain from left to right. So carbon number one, number two and number three, notice that the first double bond begins at carbon number three. And therefore, we can say that this must be an Omega three acid because this is where the first double bond starts when we enumerate from left to right. So we have our answers. We have the structure, its name and the Omega number. Thank you for watching.

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23. Lipids

Fatty Acids

GOB Chemistry

23. Lipids

Fatty Acids

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Problem 77

Textbook Question

Draw the skeletal structure and give the name and omega number of the following fatty acid:
CH₃CH₂CH₂CH₂CH₂HC=CHCH₂HC=CHCH₂CH₂CH₂CH₂CH₂CH₂CH₂COOH

Verified step by step guidance

Identify the functional groups in the molecule. The molecule contains a carboxylic acid group (-COOH) at one end, which classifies it as a fatty acid. Additionally, there are two double bonds in the hydrocarbon chain, making it an unsaturated fatty acid.

Determine the total number of carbon atoms in the molecule. Count all the carbons, including those in the hydrocarbon chain and the carboxylic acid group.

Draw the skeletal structure of the molecule. Represent the hydrocarbon chain as a zigzag line, with the carboxylic acid group (-COOH) at one end. Indicate the positions of the double bonds using double lines between the appropriate carbon atoms.

Assign the name of the fatty acid. Use the IUPAC naming system: (1) Count the total number of carbons in the chain, (2) Identify the positions of the double bonds, and (3) Use the suffix '-enoic acid' to indicate the presence of double bonds. For example, if the double bonds are at carbons 9 and 12, the name would include '9,12-'.

Determine the omega number. The omega number is the position of the first double bond when counting from the methyl end (CH₃) of the fatty acid. Count the carbons starting from the CH₃ group until you reach the first double bond, and record this position as the omega number.

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Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Fatty Acid Structure

Fatty acids are carboxylic acids with long hydrocarbon chains. The structure typically consists of a hydrophobic tail made of carbon and hydrogen atoms, and a hydrophilic carboxyl group (-COOH) at one end. Understanding the arrangement of these atoms is crucial for identifying the fatty acid's properties and classification.

Omega Number

The omega number of a fatty acid indicates the position of the first double bond from the methyl end (omega end) of the fatty acid chain. For example, in omega-3 fatty acids, the first double bond occurs at the third carbon from the methyl end. This classification helps in understanding the fatty acid's role in nutrition and health.

Skeletal Structure Representation

The skeletal structure of a molecule is a simplified representation that shows the arrangement of atoms without depicting all the hydrogen atoms explicitly. In fatty acids, this representation highlights the carbon backbone and functional groups, making it easier to visualize the molecular structure and identify features such as double bonds and chain length.

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