The kind folks at Wavefunction Inc. have supplied me with their full Odyssey general chemistry app suite and I will be reviewing each of these apps throughout the remainder of summer 2014.
This is the second of these reviews, and I will be discussing the Polar Bonds and Molecules App which is available for purchase in the app store for $3.99 CAD (https://itunes.apple.com/us/app/odyssey-polar-bonds-molecules/id869677755?mt=8)
At first, I was a little baffled why this is its own separate app, as there is a polarity function built into the VSEPR app, which was previously reviewed on this blog (http://wordpress.viu.ca/key2chem/2014/07/03/odyssey-vsepr-app-chemistry-ipad-app-review/). However, there are a few additional features built into this app which are not found in the VSEPR app.
Most first year general chemistry courses spend some time discussing chemical bonding, covering topics such as: ionic and covalent bonds, bond polarity, electronegativity, and Lewis structures. At VIU, our CHEM 140 course is no exception and covers electronegativity, determining if bonds are covalent or polar covalent, drawing polarity arrows (dipole moments), and determining net molecular dipoles. The textbook we use has a fair amount of examples and end-of-chapter questions, but these are certainly skills that many students may want to seek additional practice and resources to master.
The interface is very similar to the VSEPR app (previously reviewed). There is a portion where the molecules are featured for manipulation and a portion which lists examples and has tabs for reference data, a glossary, some additional comments, and questions.
Molecules can be rotated with a finger swipe, and expanded/shrunk with the pinch of the thumb and index finger. They can be displayed as Ball and Wire, Tube, Ball and Spoke or Space Filling models.
One feature that I really like is the ability to show the molecules as electrostatic potential diagrams, which can be enabled/disabled by clicking the “electron density” selection box on the right side just above the list of example molecules.
The ruler button allows for the calculation or the bond length, angle, and the dipole moment.
And the dipole moment can be shown using the arrow notation or as a partial charge by clicking the remaining two buttons on the left side window of the app.
In the window on the right side of the app, some examples of the common bond types are available (non-polar covalent, polar covalent and ionic). 25 additional molecules, which are not classified into the three bonding types mentioned, are also available as examples. Some guidelines towards how students should approach using the app are given in the OBSERVE! tab. A table of reference electronegativities is provided under the reference data tab, and a glossary is provided as well under its own separate tab.
The comments tab provides some additional technical notes, such as noting how to change the polarity arrow from the common use form (positive end to negative end) to the not-so-commonly used IUPAC (negative end to positive end).
The questions which are pre-loaded into the app are multiple choice and are similar to those which appear in the end-of-chapter section of most textbooks and focus on the difference between the bonding types and molecular polarity. These questions would likely get students to open up the example molecules to find the correct answers, and the questions can be scored automatically by the app.
This app does provide some additional features beyond the VSEPR app, including dipole moment calculation, and questions specific to polarity and types of bonds. Some may wonder why this was made into a seperate app, and not just included with the VSEPR app to make one really great app. I really like the use electrostatic potential diagrams, as I try to show these types of diagrams as much as possible in class.
I think a really important learning tool that could be added by the developers would be some way to have students predict the net molecular dipole moment (the direction of the polarity arrow for a molecule with more than one polar covalent bond). Many students struggle with the idea of vector summation and predicting net molecular dipole moment.
I will certainly provide a link to this app when we discuss this topic in the fall semester, and hopefully I can get some student feedback.
The author received an evaluation copy of the software from Wavefunction Inc., but received no other compensation.