Chemistry Step-by-Step Solutions: Structure and Bonding
The following was originally published on the Wolfram Blog. The original post can be viewed here.
We’re back with another post in our chemistry series, to explore molecular structure and bonding with Wolfram|Alpha and its step-by-step chemistry offerings. Read more on chemical reactions and solutions from previous posts, and keep an eye out for our final installment on quantum chemistry!
Structure and bonding in chemistry refer to where the atoms in a molecule are and what holds those atoms together. Molecules are held together by chemical bonds between the atoms comprising the molecule. Understanding the interplay between molecular structure and the electrons involved in bonding is what facilitates the design of new molecules, the control of chemical reactions and a better understanding of the molecules around us.
To master structure- and bonding-related calculations, the step-by-step solutions provide stepwise guides that can be viewed one step at a time or all at once. Read on for example problems covering Lewis structures, oxidation numbers, orbital hybridization and aromaticity.
Chemical Structure
Molecular species are not visible to the naked eye, so being able to represent them in a pictoral form is fundamental to communicating chemical information. One of the most common depictions is the Lewis structure. The step-by-step solution (introduced in 2013) walks you through counting the valence electrons, assigning them to each atom and determining the required number of bonds.
Example Problem
What is the Lewis structure of nitrogen dioxide, NO₂?
Step-by-Step Solution
In this case, you can simply enter your query, “What is the Lewis structure of NO2”.
Oxidation Numbers
Redox reactions are a huge class of chemical reactions involving the reduction of one reactant and the oxidation of another. In order to identify the reducing and oxidizing agents, the oxidation numbers for each element in a compound must be computed. The step-by-step solution walks you through partitioning bonding electrons and accounting for the electronegativity of each element.
Example Problem
Assign oxidation numbers to all of the elements in Na₂SO₄.
Step-by-Step Solution
For this type of problem, you can ask for “Na2SO4 oxidation numbers”.
Orbital Hybridization
Atomic orbitals of similar energy and the same symmetry can mix to form hybrid orbitals. These hybrid orbitals directly affect the three-dimensional arrangement of atoms in a molecule. The step-by-step solution explains how to determine orbital hybridization from the structure diagram and steric numbers.
Example Problem
What is the hybridization on each atom in succinylacetone?
Step-by-Step Solution
Finding the hybridization is easy when you enter “succinylacetone hybridization”.
Aromaticity
Aromatic compounds are a particularly stable class of organic molecules. Identifying aromaticity aids in the chemical understanding of existing molecules and in the design of new ones. The step-by-step solution identifies possible aromatic electrons and applies the Hückel rule.
Example Problem
Determine if thiophene molecules are aromatic.
Step-by-Step Solution
For this problem type, just enter your query, “Is thiophene aromatic”.
Besides identifying aromatic molecules, Wolfram|Alpha can also figure out how many aromatic atoms are in a molecule.
Example Problem
How many aromatic atoms does doxazosin contain?
Step-by-Step Solution
To get the answer, enter “doxazosin aromatic atom count”.
Challenge Problems
Test your problem-solving skills by using the Wolfram|Alpha tools described to solve these word problems on structure and bonding. Answers will be provided in the next blog post in this series.
- What is the oxidation state of hydrogen in lithium aluminum hydride?
- What is the orbital hybridization of the central atom in SF₆?
Answers to the Last Post’s Challenge Problems
Here are the answers to the last post’s challenge problems on chemical solutions.
1. A good ratio for the salt bath used in old-fashioned ice-cream makers is five cups ice to one cup salt. What is the mass fraction of the resulting mixture?
The volume-to-mass conversions need to be done in two separate Wolfram|Alpha queries.
Then pass the results into a mass fraction query.
2. What is the molality of ethylene glycol for a solution that freezes at –5.00 °C?
First, look up the cryoscopic constant for ethylene glycol.
Next, plug the retrieved information into the freezing-point depression calculator.
Join us for our final installment on quantum chemistry. And as always, if you have suggestions for other step-by-step content (in chemistry or other subjects), please let us know! You can reach us by leaving a comment below or sending in feedback at the bottom of any Wolfram|Alpha query page.
This post was written by the Wolfram|Alpha Chemistry Team.
