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Ch.2 - Atoms, Molecules & Ions
McMurry - Chemistry 8th Edition
McMurry8th EditionChemistryISBN: 9781292336145Not the one you use?Change textbook
All textbooksMcMurry 8th EditionCh.2 - Atoms, Molecules & IonsProblem 44a
Chapter 2, Problem 44a

Give molecular formulas corresponding to each of the following ball-and-stick molecular representations (red = O, gray = C, blue = N, ivory = H). In writing the formula, list the elements in alphabetical order. (a) Alanine (an amino acid)

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Identify the colors of the atoms in the ball-and-stick model: red for oxygen (O), gray for carbon (C), blue for nitrogen (N), and ivory for hydrogen (H).
Count the number of each type of atom in the ball-and-stick model of alanine.
List the elements in alphabetical order: C, H, N, O.
Write the molecular formula by combining the element symbols with their respective counts, ensuring the order is C, H, N, O.
Double-check the molecular formula to ensure all atoms are accounted for and the order is correct.

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Key Concepts

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

Amino Acids

Amino acids are organic compounds that serve as the building blocks of proteins. Each amino acid contains a central carbon atom, an amino group (-NH2), a carboxyl group (-COOH), a hydrogen atom, and a variable side chain (R group) that determines the specific properties of the amino acid. Alanine, for example, has a simple side chain consisting of a methyl group (-CH3).
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Molecular Formulas

A molecular formula represents the number and types of atoms in a molecule, indicating the composition of the substance. It is written by listing the chemical symbols of the elements present, followed by subscripts that denote the number of each type of atom. For example, the molecular formula for alanine is C3H7NO2, which shows it contains three carbon atoms, seven hydrogen atoms, one nitrogen atom, and two oxygen atoms.
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Ball-and-Stick Model

A ball-and-stick model is a three-dimensional representation of a molecule, where balls represent atoms and sticks represent the bonds between them. This model helps visualize the spatial arrangement of atoms in a molecule, which is crucial for understanding molecular geometry and reactivity. In the case of alanine, the model would illustrate the connectivity and arrangement of carbon, hydrogen, nitrogen, and oxygen atoms.
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Related Practice
Textbook Question

In the following drawings, red and blue spheres represent atoms of different elements. Match the molecular pictures (a)–(c) with the following descriptions: (i) a pure substance consisting of a compound (ii) a pure substance consisting of an element (iii) a mixture of element

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Textbook Question

Give molecular formulas corresponding to each of the following ball-and-stick molecular representations (red = O, gray = C, blue = N, ivory = H). In writing the formula, list the elements in alphabetical order. (c) Acetic acid (vinegar)

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Textbook Question

Give molecular formulas corresponding to each of the following ball-and-stick molecular representations (red = O, gray = C, blue = N, ivory = H). In writing the formula, list the elements in alphabetical order. (b) Ethylene glycol (automobile antifreeze)

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Textbook Question
How many elements are presently known? About how many occur naturally?
Textbook Question

Which represents a Ca atom with two positive electrical charges (Ca2+)? (a)

(b)

(c)


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Textbook Question

Which represents an F atom with one minus charge (F-)? (a)

(b)

(c)

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