Introductory Chemistry

19 Dec 2017

Visual scaffold for stoichiometry

Submitted by Margaret Scheuermann, Western Washington University
Description: 

These five slides are intended to share a visual scaffolding that I developed to help my general chemistry students identify what calculations are needed to solve stoichiometry problems.

 

The visual scaffold involves writing the balanced equation and then under it drawing a table with two rows and enough columns so that there is one column under each reagent in the equation. The top row is labeled as "moles" and the bottom row is labeled as "measurable quantity". Students then write in any information about a specific reagent or product that was given and identify the quantity that the question is asking them to find. They then add a series of arrows to the table to generate a "map" of how to get from the information they are given to the information they need to find with each arrow representating a type of calculation that they have already seen and practiced. Vertical arrows represent a calculation between a measured quantity and a number of moles. Horizontal arrows in the top row represent calculations between moles of one substance and moles of another substance. Horziontal arrows in the "measured quantity" row are not allowed since those unit conversion factors are not readily available. 

 

Corequisites: 
Topics Covered: 
Prerequisites: 
Course Level: 
Learning Goals: 

A student should be able to determine the quantity of a reagent required or the quantity of a product produced in a reaction.

Subdiscipline: 
Related activities: 
Implementation Notes: 

The scaffolding begins with a review of the two types of calculations that are required for basic stoichiometry: converting between grams and moles, and converting between moles of one substance and moles of another substance using the coefficients of a balanced equation as unit conversion factors (slide 1).

Some ABCD card/clicker questions can be added here if students have not practiced these types of problems in class recently.

After introducing the visual scaffold (slide 2) I do an example problem or two on the board/overhead/doc cam (slide 3).

This is a good point to give students an opportunity to work on a practice problem or if the introduction to stoichiometry began part way through a class period, an exit question.

Next I introduce situations where it could take more than one calculation to get from the measured quantity to moles (slide 4). 

An example problem and/or practice problem and/or exit question can be added here.

The visual scaffold is also relevant for limiting reagent problems. I've included an example (slide 5/6) but limiting reagent is usually presented in a subsequent class period after some examples of the limiting reagent concept using sandwiches or something similar. 

Time Required: 
30-50 minutes. varies with the number of examples and practice problems
Evaluation
Evaluation Methods: 

I will usually do an exit question- a stoichiometry problem from the textbook- after either slide 3 or slide 4. I do not require students to use the visual scaffold if they are already comfortable with stoichiometry from a previous class but many choose to use it. Some students will include the tables from the visual scaffold as part of the work they show on exams, again without being prompted or required to do so. 

31 Jul 2017

Inorganic Nomenclature: Naming Coordination Compounds

Submitted by Gary L. Guillet, Armstrong State University
Evaluation Methods: 

For my course I grade this assignment as a problem set.  Upon collecting the assignment I do not exhaustively grade them.  I check them over for completness.  I tell the students when I hand it out that it is designed for them to learn and then test their own comprehension and if they are stuck they should bring issues to office hours. 

On the following exam I put two or three inorganic complex names and have the students draw the structures.  The test questions always incorporate isomerism in addition to combinations of common ligands and transition metals.

Evaluation Results: 

After completion of this assignment most students are able to draw straigthforward structures including some isomers on an exam.  They can identify common ligands from their names like water, ammonia, carbon monoxide.  They also understand the common conventions in naming including handling cis and trans isomers as well as fac and mer isomers.

In the most recent sample of ACS examinations (IN16D) 87% of my students answerd correctly on the question most directly related to this assignment, selecting the correct name of a given complex using a picture of the complex.  I do not have any comparative data from another teaching approach.

Description: 

I do not like to take a large amount of time in class to cover nomenclature of any kind though I want students to know the names of common ligands and the basic ideas of how coordination complexes are named.  Since it is a systematic topic I assign this guided inquiry worksheet.   The students complete it outside of class and can work at whatever pace they want.  If they are more familiar with the topics the can quickly complete it but if they are rusty or have not seen some of the material it gives them an easy entry point to ask questions to fill in any gaps in their knowledge.  This assignment covers determing charge on a metal in a complex with simple ligands, how to identify and name common isomers, and it is structured in a guided inquiry form. 

Learning Goals: 

Students will be able to identify and correctly name common ligands in a chemical structure or chemical name.

Students will be able to identify the charge on a metal or a ligand in a chemical structure.

Students will be able to identify common isomeric differences in a chemical structure or a chemical formula (cis, trans, fac, mer). 

Students will be able to use a chemical name to draw a chemical structure.

Equipment needs: 

None

Topics Covered: 
Corequisites: 
Prerequisites: 
Implementation Notes: 

I use this assignment to replace a lengthy lecture on the topic of nomenclature when covering coordination chemistry.  I have students complete this assignment outside of class.  I encourage them to work in pairs so students can jointly interpret the instructions and determine the patterns in naming complexes.  The assignment is constructed in a very straightforward manner and covers the basics of inorganic nomenclature.

Upon completion of the assignment I take about 15-20 minutes in class to quickly cover the main ideas of the assignment.  I field any questions that arose during the assignment and I do a few comprehension check type questions on the board. 

Time Required: 
1-2 hours
3 Jun 2017
Evaluation Methods: 

This LO was craeted at the pre-MARM 2017 ViPER workshop and has not been used in the classroom.  The authors will update the evaluation methods after it is used.

Description: 

This module offers students in an introductory chemistry or foundational inorganic course exposure to recent literature work. Students will apply their knowledge of VSEPR, acid-base theory, and thermodynamics to understand the effects of addition of ligands on the stabilities of resulting SiO2-containing complexes. Students will reference results of DFT calculations and gain a basic understanding of how DFT can be used to calculate stabilities of molecules.

 
Prerequisites: 
Corequisites: 
Learning Goals: 

Students should be able to:

  1. Apply VSEPR to determine donor and acceptor orbitals of the ligands

  2. Identify lewis acids and lewis bases

  3. Elucidate energy relationships

  4. Explain how computational chemistry is beneficial to experimentalists

  5. Characterize bond strengths based on ligand donors

Course Level: 
Implementation Notes: 

Students should have access to the paper and have read the first and second paragraphs of the paper. Students should also refer to scheme 2 and table 2.

 

This module could be either used as a homework assignment or in-class activity. This was created during the IONiC VIPEr workshop 2017 and has not yet been implemented.

 
Time Required: 
50 min
3 Jun 2017
Evaluation Methods: 

This was created during the IONiC VIPEr workshop 2017 and has not yet been implemented.

 
Description: 

This module offers students an introductory chemistry or foundational inorganic course exposure to recent literature work. Students will apply their knowledge of VSEPR and basic bonding to predict geometries of complex SiO2-containing structures. Students will gain a basic understanding of how crystallography is used to determine molecular structures and compare experimental crystallographic data to their predictions.

Prerequisites: 
Course Level: 
Corequisites: 
Learning Goals: 

Students will be able to:

  1. Describe the bonding in SiO2 and related compounds
  2. Apply bonding models to compare and contrast bond types
  3. Apply VSEPR to predict bond angles
  4. Utilize crystallographic data to evaluate structures
Implementation Notes: 

Students should have access to the paper and read the first and fourth paragraphs on the first page and the third paragraph on the second page. Students should also reference scheme 1 and figure 1.

 

This module could be either used as a homework assignment or in-class activity.

 
3 Jun 2017
Evaluation Methods: 

This learning object was created at the pre-MARM workshop in 2017 and as such has not been used in a classroom setting. The authors will update the learning object once they have used it in their classes.

Description: 

This module offers students in an introductory chemistry or foundational inorganic course exposure to recent literature. Students will apply their knowledge of Lewis dot structure theory and basic thermodynamics to compare and contrast bonding in SiO2 and CO2.

Corequisites: 
Course Level: 
Prerequisites: 
Learning Goals: 

Students should be able to:

  1. Describe the bonding in SiO2 and related compounds (CO2)

  2. Use Lewis dot structure theory to predict bond orders

  3. Apply bonding models to compare and contrast bond types and bond energies (sigma, pi)

  4. Characterize bond strengths based on ligand donors

Implementation Notes: 

Students should read the first paragraph of the paper prior to completing this learning object. They can be encouraged to read more of the paper, but the opening paragraph is the focus of this learning object.

Time Required: 
50 min
26 Mar 2017

Formulas and Nomenclature of Compounds

Submitted by Sarah Shaner, Southeast Missouri State University
Evaluation Methods: 

The activity was not graded. After students work through the problems in pairs, we come back together as a class and discuss any problems that caused the students trouble.

Description: 

Students will be given the formula for a cation or anion on a slip of paper or index card. He or she will find another student with an ion with the opposite charge and practice writing the formula and naming the ionic compound that would result by combining the cation and anion. Students also answer a few questions about naming and formulas of binary molecular compounds with their partner.

Learning Goals: 
  • Become better acquainted with their classmates and get used to working in groups.
  • Construct formulas for ionic compounds based on ion charges.
  • Practice naming ionic and molecular compounds based on their formulas.
Corequisites: 
Prerequisites: 
Equipment needs: 

The instructor will need scissor and/or index cards to prepare the slips of paper or cards with ion names on them.

Topics Covered: 
Course Level: 
Subdiscipline: 
Implementation Notes: 

I typically give cations to one half of the room and anions to the other half. This means that students must move around the room to find a suitable partner. Since this is early in the semester, this helps with getting students to talk and work with people in the class they may not know.

Time Required: 
About 20 minutes
25 Mar 2017

KINETICS - Computations vs. Experiment

Submitted by Teresa J Bixby, Lewis University
Evaluation Methods: 

- determine the activation energy of a reaction from an energy diagram

- determine the rate constant for the reaction from the activation energy

- determine the rate law and rate constant for a reaction from experimental data

 

These Learning Objectives will be assessed on a subsequent exam.

Evaluation Results: 

Most students did not have a problem determining the rate constant from the activation energy (from an energy diagram). From what mistakes there were, the most common mistake was choosing the wrong starting energy (choosing the product energy rather than the reactant energy to start). Most students were also able to determine the rate constant from experimental data, especially if there were clearly 2 experiments where only one reactant concentration was doubled for each reactant. Changing the factor by which the reactant concentration changed (1.3 for example), or including experimental data where two reactant concentrations changed at the same time, seemed to cause more problems. 

Description: 

<p>This activity has students use Spartan to build an energy diagram for an SN2 reaction as a function of bond length. The activation energy can then be used to determine the rate constant for the reaction. After a few intoductory questions to orient general chemistry students to the organic reaction (with a short class discussion), the instructions lead them step-by-step to build the energy diagram for CH&lt;sub&gt;3&lt;/sub&gt;Cl + Cl- --&gt; Cl- + CH&lt;sub&gt;3&lt;/sub&gt;Cl. Any questions about how to use the program or descriptions of the levels of theory are given during the class period. The questions, class discussion, and Spartan tutorial for the first reaction can be compelted in one 50 min period.&nbsp;</p><p>The rest of the activity is completed as an assignment. Other anions attack CH&lt;sub&gt;3&lt;/sub&gt;Cl and students consider which product is more stable. They also compare the computational rate constant for OH- attacking with a rate constant determined from experimental data. They find that Spartan is good for molecular modeling but the absolute value of the energies of the transition states are inaccurate.&nbsp;</p><p>SN2 reactions with more complex molecuels may be more illustrative.&nbsp;</p><p>In the future we hope to develop this activity into an in-class prelab where then students can collect the experimental data on their own.&nbsp;</p>

Learning Goals: 

- use Spartan to build molecules and a transition state

- determine the activation energy of a reaction from an energy diagram

- determine the rate constant for the reaction from the activation energy

- determine the rate law and rate constant for a reaction from experimental data

- relate reactant and product energies to leaving group character

- compare computation to experiment

Prerequisites: 
Corequisites: 
Equipment needs: 

Need to have access to Spartan Student.

Topics Covered: 
Course Level: 
Subdiscipline: 
Implementation Notes: 

Building the transition state seems to be the most confusing part for General Chemistry students who have not used Spartan before. Encouraging them to limit twirling the molecule around a lot before they have completed this step seems to help. I intend to clarify these instructions before the next implementation. 

A different base molecule may yield better agreement with experimental data. This will aslo be explored before the next implementation.

Time Required: 
50 min + out-of-class assignment (~5 days)
18 Jan 2017

calistry calculators

Submitted by Adam R. Johnson, Harvey Mudd College
Description: 

I just stumbled on this site while refreshing myself on the use of Slater's rules for calculating Zeff for electrons. There are a variety of calculators on there including some for visualizing lattice planes and diffraction, equilibrium, pH and pKa, equation balancing, Born-Landé, radioactive decay, wavelengths, electronegativities, Curie Law, solution preparation crystal field stabilization energy, and more.

I checked and it calculated Zeff correctly but I can't vouch for the accuracy of any of the other calculators. 

Prerequisites: 
Corequisites: 
Learning Goals: 

This is not a good teaching website but would be good for double checking math

 

Implementation Notes: 

I used this to double check my Slater's rules calculations (and found a mistake in my answer key!)

27 Jul 2016

Symbolize It All

Submitted by Fabiola Barrios Landeros, Yeshiva University
Evaluation Methods: 

This activity was tried as a stretch break during a summer program for a group of about 25 high school students at Columbia Univesity. 

Evaluation Results: 

All students jumped in the activity. They worked mostly individually to explore the possible spellings of their names or last names.

Once done, they spelled the names with symbols on post-it notes and pasted them on the side wall. This classroom was used exclusively for a summer program, so students left up their post its as decorations during the following weeks.

Since I had the answer key with the "symbolized" roster, I pointed out the names that were missing and gave them hints and a couple extra minutes to complete the task.

About one third of the class was able to "symbolize" their first name or last name.

We declared as winners the student that used the most symbols and the student that had three different ways to spell her last name. They won a small periodic table poster.

The whole activity took 12-15 min. 

Description: 

This is an HTML program that helps you spell with symbols of chemical elements for anything you want. Just cut and paste the text, paragraph or list of names you would like to "symbolize" in the left field. The program automatically displays the words that could be spelled with chemical symbols in the right field. When a word has more than one possible spelling, all of the possible combinations are displayed on a single line.

The program is compatible with most web browsers and it is simple to use. Just download the file and click to open. It will automatically open in your default browser. 

 
NOTE: The creative commons license applies to this specific LO. The Copyright and License from the author of the HTML program is described in the file. I obtained this file from the author with verbal permision to post and distribute it on ionicviper.org.  
Learning Goals: 

Students will review names and symbols of the elements in the periodic table.

Student and instructor will get acquainted and learn the names of some of their classmates. 

Instructor will break the ice with an educational and friendly competition.

 

Corequisites: 
Subdiscipline: 
Course Level: 
Equipment needs: 

Large periodic table in your classroom or an image projected from your computer. 

Instructor should "translate" the class roster into chemical symbols ahead of time and bring the print out of the answer key to class. 

Board to write the answers. 

Square post-it notes and markers (optional).

Topics Covered: 
Prerequisites: 
Implementation Notes: 
The activity will engage students with the periodic table, break the ice and help the instructor remember the names of some students. This could be used on the first day of an intro chem class. 
 
Challenge students to try to spell their first name and/or last name using only symbols of chemical elements.
 
Make sure there is a large periodic table in your classroom, otherwise project an image from your computer. 
 
Once they find a spelling, they can write it on the board or spell their names using square post-it notes and markers to decorate the wall.  
 
Example:
  
    
 
Set up a contest and give a small price (like a periodic table) for the one that used the most elements, or the one that could spell his/her name AND last name, the one that adds up the highest atomic numbers, the one with two alternative spellings, etc. 
 
Instructors should "translate" the class roster into chemical symbols ahead of time and bring the print out of the answer key to class. In this way, the instructor can tell which names are missing and challenge students to keep trying. Don't forget to include also the names of TAs'and your own name to participate.
 
Students need about 5 minutes to explore the periodic table and find a "symbolized" spelling of their names and a couple of minutes to post the answers where everyone can see them. Instructor can then check the names that are missing (give them a hint) and give extra 3 minutes to try again.
 
OTHER POSSIBLE APPLICATIONS:

This program can have a diverse list of applications. You wil find it very useful whether you are breaking the ice on the first day of classes, writing a novel only using chemical symbols or choosing a chemical baby name.

TRIVIA: Did you know? Using the data from the US Census, 12% of all girls names and 16% of all boys names can be spelled with element symbols.

And the winning names with the most spellings are:

For girl, Ninasimone: ['NINAsIMoNe', 'NINaSIMoNe', 'NINaSiMoNe', 'NInAsIMoNe', 'NiNAsIMoNe', 'NiNaSIMoNe', 'NiNaSiMoNe']

For boy, Kostandinos: ['KOSTaNdINOS', 'KOSTaNdINOs', 'KOSTaNdINoS', 'KOSTaNdInOS', 'KOSTaNdInOs', 'KOsTaNdINOS', 'KOsTaNdINOs', 'KOsTaNdINoS', 'KOsTaNdInOS', 'KOsTaNdInOs']

 

 

 

Time Required: 
This exercise can be used as a 15 min ice breaker for the first day of intro chem.
30 Jun 2016

Chemical Information Available on the Web

Submitted by Matthew Riehl, Bethany Lutheran College
Evaluation Methods: 

Typically the assignment is assessed based on how thoroughly the report is completed. It should be noted that the results often depend on the search terms chosen, and a difficult topic should not penalize the student.  When choosing a chemical to find information on, the students select a CAS registry number and (all too often) choose a number that relates to an inert ingredient or uncharacterized component, for which no chemical information is available.  

Evaluation Results: 

Students typically do well if they spend the time.  The most common omission is including the interlibrary loan material with the report (we have a small library and rely heavily on ILL)

 

Description: 

This exercise introduces students to many chemical resources found on the internet.  Rather than being geared for upper-division chemistry majors, much of the material introduced is appropriate for freshmen and sophomore level students (although more advanced students will also benefit from the exercise).  The “web guide” contains links to many search engines and resources with brief descriptions of each while the “web report” has a number of exercises that asks students to search for chemical information.  The assignment is self-guided; students are encouraged to choose topic of interest to them.  Notably, this assignment does not introduce ACS or other chemical journal sites or SciFinder, but does introduce resources (many .gov) geared for the general population.

Learning Goals: 

In completing this assignment, students will become familiar with internet search engines and other web based resources for chemical information, toxicity information, drug information, etc.  In addition, links to several free chemical structure drawing tools are provided.

 

Equipment needs: 

Computers and internet access -- I typically meet in a computer lab and students often complete the assignment on their own time.

Course Level: 
Corequisites: 
Prerequisites: 
Implementation Notes: 

I have used this as a laboratory exercise, but may also be a homework assignment.  My primary observations are that the students suffer from “information overload” after working on this assignment for an entire lab period, and that students do not always retain the knowledge to the next semester.  It may be a good idea to plan additional assignments to reinforce these search engines during the semester.  I also ensure that the Web-Guide is always available to the students as a resource.

Time Required: 
At least three hours.

Pages

Subscribe to RSS - Introductory Chemistry