Textbook Question
Propose structures and draw condensed formulas for molecules that meet the following descriptions.
(a) A ketone with the formula C5H10
Ch.23 - Organic and Biological Chemistry
Chapter 23, Problem 23.57a
Give line drawings for each of the following molecular formulas. You may have to use rings and/or multiple bonds in some instances.
(a) C2H7N
Verified step by step guidance1
Step 1: Identify the number of valence electrons for each atom. Carbon (C) has 4, Hydrogen (H) has 1, and Nitrogen (N) has 5.
Step 2: Calculate the total number of valence electrons in the molecule. For C2H7N, there are 2 Carbon atoms, 7 Hydrogen atoms, and 1 Nitrogen atom. So, the total number of valence electrons is (2*4) + (7*1) + (5*1) = 18.
Step 3: Start drawing the structure by connecting the atoms with single bonds. Carbon atoms are usually in the center of organic molecules, so connect the two Carbon atoms together. Then, connect the Nitrogen atom to one of the Carbon atoms.
Step 4: Distribute the remaining electrons as lone pairs or multiple bonds to satisfy the octet rule for each atom (except Hydrogen, which only needs 2 electrons). Nitrogen needs 3 more electrons, so add them as lone pairs. Each Carbon atom needs 3 more electrons, so connect each Carbon atom to 3 Hydrogen atoms.
Step 5: Check your structure. Each atom should have a full outer shell (2 electrons for Hydrogen, 8 electrons for Carbon and Nitrogen). If not, you may need to form double or triple bonds. In this case, the structure should be correct as is.
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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Molecular Structure
Molecular structure refers to the arrangement of atoms within a molecule, including the types of bonds (single, double, or triple) and the spatial orientation of these atoms. Understanding molecular structure is crucial for drawing accurate line representations, as it dictates how atoms are connected and how they interact with one another.
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Molecular Formula
Line Drawings
Line drawings, or skeletal structures, are a simplified way to represent organic molecules. In these drawings, carbon atoms are represented by the ends and intersections of lines, while hydrogen atoms are often omitted for clarity. This method allows chemists to visualize complex structures quickly and efficiently, focusing on the essential features of the molecule.
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Functional Groups
Functional groups are specific groups of atoms within molecules that are responsible for the characteristic chemical reactions of those molecules. In the case of C2H7N, recognizing the presence of an amine functional group (–NH2) is essential for accurately depicting the molecule's structure and understanding its reactivity and properties.
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Related Practice
Textbook Question
Propose structures and draw condensed formulas for molecules that meet the following descriptions.
(b) An ester with the formula C6H12O2
Textbook Question
Propose structures and draw condensed formulas for molecules that meet the following descriptions.
(c) A compound with formula C2H5NO2 that is both an amine and a carboxylic acid
Textbook Question
Methionine, one of the 20 amino acid building blocks from which proteins are made, has the following structure. What is the chemical formula of methionine? In writing the for-mula, list the element symbols in alphabetical order, and give the number of each element as a subscript.