General Chemistry

16 Jan 2020

Time-Integrated Rate Laws and the Stability of Gold(III) Anticancer Compounds

Submitted by Jack F Eichler, University of California, Riverside
Evaluation Methods: 

1) Performance on the pre-lecture online quiz

2) Performance on the in-class activity (clicker scores or hand-graded worksheet)

 

Evaluation Results: 

Students generally score on average 70% or higher on the pre-lecdure quiz, and on average 70% or more of students correctly answer the in-class clicker questions. 

Description: 

This is a flipped classroom module that covers the concepts of time-integrated rate laws. This activity is designed to be done at the end of the typical second quarter/second semester general chemistry kinetics unit. Students will be expected to have learned the following concepts prior to completing this activity:

a) how instantaneous rates of reactions are determined by measuring changes in concentration of reactants and/or products at the beginning of the reaction;

b) understanding basic rate laws and how rate laws are determined for a chemical reaction using instantaneous rates;

c) understanding why the rates of reactions slow down as the time of reaction increases.

Acknowledgement: This material is based upon work supported by the National Science Foundation under Grant No. 1504989. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation.

 

Learning Goals: 

Students are expected to achieve the following learning goals:

a) conceptually understand how time-integrated rates laws can be used to describe the kinetics of a chemical reaction;

b) use time-integrated rate laws to determine the rate constant for a first or second order reaction;

c) use time-integrated rate laws to determine the half-life of a decomposition reaction;

d) use Excel to plot time-integrated rate laws and generate best-fit linear trend lines.

 

Corequisites: 
Equipment needs: 

Students need a laptop or tablet device capable of operating a spreadsheet/graphing program. 

Course Level: 
Prerequisites: 
Topics Covered: 
Subdiscipline: 
Implementation Notes: 

See attached instructor notes. 

Time Required: 
50-80 minutes
2 Jan 2020

Reaction Mechanisms: Energy Profiles and Catalysts

Submitted by Wesley S. Farrell, United States Naval Academy
Evaluation Methods: 

Students will report answers to the class.  The instructor should use the quality of these responses to gauge understanding.

Evaluation Results: 

N/A

Description: 

This in class activity consists of two demonstrations to be performed by the instructor, followed by a worksheet that students may work on independently or in groups.  The demonstrations allow the students to determine when a reaction has occured, when it has not occured, and generate qualitative reaction energy profiles to match these observations.  This activity is designed to take place during a description of kinetics in general chemistry. Detailed descriptions of the procedure and activity may be found in the "Overview for Instructor."

Learning Goals: 

Students should be able to create qualitative reaction energy profiles which match a series of reactions, catalyzed and uncatalyzed.

Subdiscipline: 
Equipment needs: 
  • Three 8” test tubes
  • 3% H2O2
  • Small cubes of potato, both raw and cooked
  • 250 mL Erlenmeyer flask
  • Pt spiral (preferably in glass tube with hook for support)
  • Methanol
  • Bunsen burner (with striker)

 

Course Level: 
Corequisites: 
Prerequisites: 
Topics Covered: 
Implementation Notes: 

Please see the "Overview for Instructor" document for implementation notes.

Time Required: 
15 minutes
5 Dec 2019

Flipped Class Module - Lewis Structures of Industrially and Environmentally Relevant Molecules

Submitted by Jack F Eichler, University of California, Riverside
Evaluation Methods: 

1) Performance on the pre-lecture online quiz

2) Performance on the in-class activity (clicker scores or hand-graded worksheet)

 

Evaluation Results: 

Students generally score on average 70% or higher on the pre-lecdure quiz, and on average 70% or more of students correctly answer the in-class clicker questions. 

Description: 

This is a flipped classroom activity intended for use in a first semester general chemistry course. Students are expected to have prior knowledge in identifyng the difference between molecular and ionic compounds, understanding the conceptual framework for how covalent bonds form, and how to draw Lewis dot symbols for atoms, and how to determine the number of valence electrons for atoms.



The activity includes:

1) pre-lecture learning videos that guide students through learning how to draw valid Lewis structures, determining how to caculate the formal charge for atoms in molecular compuonds/Lewis structures, and using formal charge to determine which Lewis structure is most stable if multiple Lewis structures are possible for a given molecule;

2) pre-lecture quiz questions; and

3) an in-class activity that requires students to apply their knowledge of chemical bonding in drawing Lewis structures.

Acknowledgement: This material is based upon work supported by the National Science Foundation under Grant No. 1504989. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation.

Learning Goals: 

Students should be able to:

a) draw Lewis structures of molecular compounds;

b) determine the formal charge of atoms in molecular compounds;

c) use formal charge to predict the most stable Lewis structure.

 

Equipment needs: 

Suggested technology:

1) online test/quiz function in course management system

2) in-class response system (clickers)

Course Level: 
Corequisites: 
Prerequisites: 
Implementation Notes: 

Attached as separate file. 

Time Required: 
50-80 minutes
18 Oct 2019

Mechanisms of Mn-catalyzed water oxidation reactions

Submitted by Margaret Scheuermann, Western Washington University
Evaluation Methods: 

I did not grade this activity. 

Evaluation Results: 

Three students out of 14 explicitly mentioned that this activity was helpful on the free response section of the course evaluations.

 

Description: 

This LO is an in-class assignment to prepare students for literature readings involving catalytic cycles in which multiple protons and electrons are transferred. Two catalytic mechanisms, a proposed OEC mechanism and the proposed mechanism of a biomimetic OEC complexes are included. The intermediates are drawn including all charges and oxidation states, details which are sometimes omitted in the primary literature but can be helpful to students who are not accustomed to looking at multistep catalytic cycles. Students are then asked to add in the substrates and products entering and leaving the catalytic cycle. While this is, at its heart, a stoichiometry excercise, it helps calibrate students for the level of attention to detail needed to effectively engage with reading about bioinorganic catalytic mechanisms.

Learning Goals: 

After completing this activity:

A student will be able to follow along with each step in  proposed water oxidation mechanims in the literature.

A student will be able to apply their knowledge of stoichiomety to complex catalytic cycles involving electron transfer.

A student will be able to analyze and compare the details of catalytic cycles.

Corequisites: 
Subdiscipline: 
Prerequisites: 
Implementation Notes: 

I used this activity during a lab lecture before an inorganic laboratory experiment in which students would be preparing and testing an OEC mimic. The procedure we used was roughly based on a published procedure (J. Chem Ed. 2005, 82, 791) linked in web resources. 

I began the class period with a brief introduction to the chemistry of photosynthesis and where water oxidation and PSII fit in the broader picture. I then introduced the mimic that students would be preparing and the chemistry of the Oxone (R) triple salt. 

Students then worked in groups to complete this activity and discuss their structural and mechanistic observations. After the activity they were encouraged to read the papers referenced in the activity and to think about the evidence that supports the proposed mechanism.

 

Other implementation options:

While I used this activity as part of a lab lecture it could also be used to stimulate a discussion comparing structure/mechanism of biological and biomimetic systems in a lecture setting without the accompaning laboratory work.

This could also be modified for use as an equation balancing excercise in a majors or honors general chemistry course.

Time Required: 
10-20 minutes
18 Jul 2019

Science Information Literacy Badge--Reading the Literature

Submitted by Michelle Personick, Wesleyan University
Evaluation Methods: 

I use this activity as a "badge," which is self-paced guided skill-building activity that students complete on their own time outside of class. Badges are designed around fundamental chemistry skills that students wouldn’t necessarily acquire from standard course content and lectures. They carry a very small point value (about 2% of the course total per badge) but my students are very motivated by even small amounts of points. I assign points primarily based on completion and effort and also provide brief written feedback for each student. I have my students turn in badges in Moodle, which makes feedback more streamlined.

Description: 

This is an activity designed to introduce general chemistry students to reading the chemistry literature by familiarizing them with the structure of a published article. The activity first presents an article from the Whitesides group at Harvard about writing a scientific manuscript, along with a video about the peer-review process. There are two parts to the questions in the activity, which are based on a specific article from Nature Communications (doi.org/10.1038/s41467-019-08824-8). Part I is focused on the structure of the article and where to find key pieces of information. Part II encourages students to use general audience summaries in combination with the original article to best understand the science while making sure they get a complete and accurate picture of the reported work.

Prerequisites: 
Course Level: 
Corequisites: 
Learning Goals: 

A student should be able to approach the chemistry literature and determine where to find:

  • the authors and their affiliations;
  • the main objective of the research;
  • the main outcomes of the research;
  • why the research is important;
  • experimental details;
  • supplementary figures and other information. 

A student should be able to broadly evaluate the reliability of secondary summaries of scientific articles by comparing them against the key points of the original paper.

Implementation Notes: 

This activity is based on a specific article: "Room temperature CO2 reduction to solid carbon species on liquid metals featuring atomically thin ceria interfaces" (Nat. Commun., 2019, 10, 865. doi.org/10.1038/s41467-019-08824-8). However, it's easily adapted to other articles that are more suited to a particular course, and I've used other articles in previous iterations. This article was chosen because the content is at least partly accessible to students in my second semester general chemistry course, who have already had some electrochemistry/redox chemistry, and who have recently learned about kinetics, reaction mechanisms, and catalysis. The topic of liquid metals is new and interesting to the students, because it's not something the'd normally be exposed to, and the application to CO2 sequestration is something they can connect with. 

 

8 Jun 2019

VIPEr Fellows 2019 Workshop Favorites

Submitted by Barbara Reisner, James Madison University

During our first fellows workshop, the first cohort of VIPEr fellows pulled together learning objects that they've used and liked or want to try the next time they teach their inorganic courses.

2 Jun 2019

Maths for Chemists

Submitted by David Harding, Walailak University
Description: 

Chemistry requires mathematics in almost all areas but it is a subject many students struggle with. This short booklet introduces mathematics from basic concepts to more advanced topics. A particularly nice feature is that examples of chemistry calculations are included so that students can understand why they have learn mathematics at all. This resource comes from the Royal Society of Chemistry's Learn Chemistry website.

Prerequisites: 
Corequisites: 
Course Level: 
6 May 2019
Evaluation Methods: 
  • The instuctor walked around the classroom to help students individually as needed for immediate assessment.
  • At the end of the class period, students submitted their work to Blackboard for grading.
  • Assignments were graded based on accuracy and quality of the drawings.
Evaluation Results: 

Students generally were able to determine the molecular formula and generate connectivity drawings of the displayed 3-D structures, but really struggled with 3-D drawing. Although this was developed for a course with second year students who had completed general chemistry, even older students in the course struggled with this component. However, by the end of class, all students greatly improved in their ability to understand, interpret, and convey 3-D structure. 

Many students were surprised and many jokes were made about this being a chemistry art class. Although some students didn't particularly enjoy drawing, all understood the value and felt like they had learned something useful. At the end of the semester, many students remarked that the chemical drawing section was the most useful or interesting. 

Description: 

This in-class activity was designed for a Chemical Communications course with second-year students. It is the first part of a two-week segment in which students learn how to use Chemdraw (or similar drawing software) to create digital drawings of molecules.

In this activity, students are given a blank worksheet and 5 models of molecules were placed around the classroom. Students interpreted the 3-D models to determine molecular formulas, connectivity, and generate drawings that convey the 3-D elements. Once students completed the worksheet by hand, they generated the whole worksheet using Chemdraw.

Learning Goals: 

Students will be able to:

1.    Write the formula for a molecule based on a 3-D structure.

2.    Draw a molecule based on a 3-D structure.

3.    Convey 3-D structure of a molecule in a drawing.

4.    Translate molecular connectivity to a drawing that conveys 3 dimensions.

5.    Create digital drawings of molecules using Chemdraw or similar chemical drawing software.

Equipment needs: 
  • Molecular model set for the instructor to prepare structures before class.
  • One computer per student with chemical drawing software such as Chemdraw.
Course Level: 
Implementation Notes: 

Prior to the activity, students were given a brief presentation with an introduction to basic Chemdraw elements using the Chemdraw manual and existing tutorials (see links provided). VSEPR was also reviewed.

For the activity, students were given 3-D models of molecules, and the color key for atom identity was written on the board (eg. blue = oxygen, black = carbon...). The activity was conducted in a class of 24 students, in which each student had access to a computer. The entire class period was 1 hour 50 min, but the activity could be shortened if fewer molecules are included.

Before class, the instructor built models of molecules using a molecular model kit. It is helpful to have multiple copies of each molecule, especially for a larger class, but not critical. The molecules used for the acitvity can be seen in the faculty-only key, and were chosen to have a range of 3-D structures, but other molecules could be chosen. For example, a coordination chemistry or upper division course could have 3-D printed models of crystal structures used as the starting point. 

Time Required: 
60 min
12 Feb 2019

Advanced ChemDraw (2019 Community Challenge #2)

Submitted by S. Chantal E. Stieber, Cal Poly Pomona
Evaluation Methods: 

Students were evaluated during class for effort and participation, and the instructor gave immediate tips and feedback. After students submitted the assignment, it was graded for completion and effort.

 

Evaluation Results: 

Students were allowed to turn in the assignment 2 days later and 22/24 students completed the assignment. The most common errors were slight variances in bond angles and missing colors used in the literature figures. Overall, the quality of the submitted work was impressive, especially for second-year students.

Description: 

This in-class activity was designed for a Chemical Communications course with second-year students. It is the second part of a two-week segment in which students learn how to use ChemDraw (or similar drawing software to create digital drawings of molecules).

In this activity, students learn advanced techniques to visualize complex organometallic molecules and reaction schemes using ChemDraw. Students are presented with several images and reaction schemes taken directly from the organometallic literature and are tasked with recreating the images using ChemDraw. This gives students direct exposure to current literature, while learning useful skills in chemical visualization.

Learning Goals: 

Students will be able to:

1.    Convey 3-D structure of a molecule in a drawing.

2.    Recreate molecular drawings found in the literature.

3.    Create digital drawings of molecules using ChemDraw.

4.    Create digital drawings of reaction schemes & cycles.

Equipment needs: 

Computer for each student with ChemDraw installed.

Implementation Notes: 

This was implemented in a 24-student course in the week following an introduction to basic ChemDraw use. Students were shown the techniques in lecture format using the attached Powerpoint presentation. After the presentation, students had access to the slides and could refer to them while completing the activity. 

In-class most students were mostly able to complete the worksheet using the powerpoint slides as a guide. However, the instructor also walked around to give individual tips and instruction. 

The total time for the activity and lecture was 1 hour 50 min, but it could be shortened or assigned for homework.

In the section where students are asked to interpret molecular formulas, this is done ignoring ligand abbreviations, such as R groups or simplifications of chelating ligands. This could be left off, however it was a useful way to introduce students to drawing simplifications they may find in the literature. Most students just interpreted the formula based on what was drawn, and some students looked up the original papers to get a more accurate formula (although this takes much more time). 

 

Time Required: 
60-110 min

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