Chem21 Demo Assignments
Virtual Labs, Timed Quizzes, Tutorials and Homework

Labs - click a lab below to launch the demo version and work through it as a student. Your lab data and calculations will not be saved after you log out - to set up a class where data / calculations are saved, email support@chem21labs.com and we will make it happen.

What we tell our students is true for professors too . . . . READ, READ, READ. These sample labs are easy to navigate if you read the information and click the "More Information" links to expand sections of the webpage. The key to navigation is to click the Next Problem button in the side panel to scroll the page . . . . then, click the Submit button to enter your answer.
Chem21 Sample Lab

This demo lab introduces the wide variety of 'components' available to uniquely customize your lab. Click the image above to launch the lab.

. . . this demo lab introduces the wide variety of 'components' available to uniquely customize your lab. Click the image above to launch the lab.

The sample lab can be assigned at the beginning of the course to introduce the student to the following lab-submission activities in a non-graded assignment:

  1. data entry
  2. image uploads
  3. calculations
  4. balancing equations
  5. essays
  6. multiple choice answers
  7. multiple select answers
  8. fill-in-the-blank answers
  9. chemical structures as answers
  10. graphing
  11. changing incorrectly-entered lab data

Chem21Labs are YOUR LABS in our format. You provide an Excel version of your lab and in 2-6 hours we transform a single-submission, delayed-feedback, grade-intensive lab into an interactive webpage with the following features:

  1. students get multiple attempts
  2. students receive immediate feedback on incorrect answers . . . . students learn more
  3. students receive an immediate grade on all submissions except essay answers and image uploads
  4. the student's lab report is saved in the Chem21 database
  5. grading is consistent for everyone
  6. essay grading is fast and consistent with our unique menu-driven grading page
  7. the points awarded by a TA and their comments on essays and image uploads are saved as a permanent record in the Chem21 database
  8. Chem21 web reports provide immediate grades on student results - you tell us your grading rubric and our program does the rest. If the lab has an unknown, simply supply the "secret" key and our code matches it up with the actual unknown.


Chem21Labs Brochure

Chem21Labs Overview

Traditional Labs - we do not have a list of labs to choose from because we quickly learned that professors have selected labs with pedagogical value, have tweaked them to work at their university and have purchased the equipment and chemicals to perform those labs. Our mission is to transform YOUR LABS into an interactive webpage . . . . click the image to the right to access a detailed description of the features we can use to build customized webpages for YOUR LABS. The virtual labs and hybrid labs described below contain an HTML5-JavaScript interactive lab animation that "sits" on our customized webpage where feedback and grading occurs in real-time enhancing the learning experience. When you work any of these labs as a student, the features you see can be used with your hands-on campus labs.

Virtual Labs and Pre-Labs - we have created (and are creating) a variety of virtual labs that are being used as pre- and post-lab assignments, make-up labs and snow-day labs at the college level. We have also created hybrid labs (part virtual, part hands-on) that are used for college distance learning courses and for high school labs (public, private and home-school) where chemicals and equipment pose significant limitations. The goal of our "at home" labs is to minimize the cost and expand the learning by supplementing simple, easy to accomplish, hands-on labs with a virtual component where students interact with equipment and instruments that are only found in well-equipped labs. These virtual labs are embedded into our online lab submission program . . . . students collect virtual data, submit it as they would real data and then submit the lab calculations, with multiple attempts and full/partial credit automatically awarded. Chem21VirtualLabs are highly engaging while providing each student with a different set of lab data.


Are you interested in creating virtual labs?
We have identified over 75 labs (there's probably 75 more) that we would like to have in the Chem21VirtualLabs Collection . . . . we need help. We have created 17 virtual / hybrid labs to date (shown below). If you can "do things" in Excel that make you the "go to" person in your department AND have a desire to create long-lasting, web-based animations that will be used by students around the world, check out this webpage for details about a free online workshop hosted by Chem21Labs.


For each of the labs listed below, mouseover the text underneath the lab to display more lab details. If you want to work through the lab as a student, you can click the lab image to seamlessly open the lab using a "demo" account.
This lab introduces the factor-unit method and dimensional analysis. An interactive 'unit map' is used to guide students through the 'set up' phase of conversions of length, area, mass and volume. The dimensional analysis problem is automatically graded. Students receive real-time feedback on the individual parts that are incorrect and opportunity to correct any mistakes. Click the image above to launch the lab.

. . . this lab introduces the factor-unit method and dimensional analysis. An interactive "unit map" is used to guide students through the "set up" phase of conversions of length, area, mass and volume. The dimensional analysis problem is automatically graded. Students receive real-time feedback on the individual parts that are incorrect and opportunity to correct any mistakes. Click the image above to launch the lab.
This lab provides guided practice on dimensional analysis problems. The Dimensional Analysis Map 1 has been expanded to include cubic length, density, molar mass, moles, amu, and Avogadro's number. The dimensional analysis problem is automatically graded. Students receive real-time feedback on the individual parts that are incorrect and opportunity to correct any mistakes. Click the image above to launch the lab.

. . . this lab provides guided practice on dimensional analysis problems. The Dimensional Analysis Map 1 has been expanded to include cubic length, density, molar mass, moles, amu, and Avogadro's number. The dimensional analysis problem is automatically graded. Students receive real-time feedback on the individual parts that are incorrect and opportunity to correct any mistakes. Click the image above to launch the lab.
This lab provides guided practice on dimensional analysis problems. The Dimensional Analysis Map 2 has been expanded to include Molarity. The dimensional analysis problem is automatically graded. Students receive real-time feedback on the individual parts that are incorrect and opportunity to correct any mistakes. Click the image above to launch the lab.

. . . this lab provides guided practice on dimensional analysis problems. The Dimensional Analysis Map 2 has been expanded to include Molarity. The dimensional analysis problem is automatically graded. Students receive real-time feedback on the individual parts that are incorrect and opportunity to correct any mistakes. Click the image above to launch the lab.
This lab provides guided practice on dimensional analysis problems. The Dimensional Analysis Map 3 has been doubled with the right half mirroring the left half. The units on the left belong to a reactant or product in a chemical reaction and the units on the right belong to a different reactant or product in the reaction. The molar ratio from the balance chemical reaction provides the bridge from the left half to the right half. The dimensional analysis problem is automatically graded. Students receive real-time feedback on the individual parts that are incorrect and opportunity to correct any mistakes. Click the image above to launch the lab.

. . . this lab provides guided practice on dimensional analysis problems. The Dimensional Analysis Map 3 has been doubled with the right half mirroring the left half. The units on the left belong to a reactant or product in a chemical reaction and the units on the right belong to a different reactant or product in the reaction. The molar ratio from the balance chemical reaction provides the bridge from the left half to the right half. The dimensional analysis problem is automatically graded. Students receive real-time feedback on the individual parts that are incorrect and opportunity to correct any mistakes. Click the image above to launch the lab.
This lab introduces the scientific method, data collection, graphing data and drawing conclusions. Students use 'virtual pennies' to navigate through the scientific method and make unexpected discoveries. Click the image above to launch the lab.

. . . this lab introduces the scientific method, data collection, graphing data and drawing conclusions. Students use "virtual pennies" to navigate through the scientific method and make unexpected discoveries. Click the image above to launch the lab.
Students determine the density of pre-1982 and post-1982 pennies using water displacement. The discovery that the densities are different explains the graph generated in the Scientific Method 1 lab. Students use an interactive 'density slider' to assist them in developing an equation where they solve for the fraction of copper and zinc in pre-1982 and post-1982 pennies. Click the image above to launch the lab.

. . . students determine the density of pre-1982 and post-1982 pennies using water displacement. The discovery that the densities are different explains the graph generated in the Scientific Method 1 lab. Students use an interactive "density slider" to assist them in developing an equation where they solve for the fraction of copper and zinc in pre-1982 and post-1982 pennies. Click the image above to launch the lab.
The discovery that there are two types of 'Penny' that differ only in their weights allows the introduction of isotopes. In this lab, students determine the fraction of <sup>2.5</sup>P and <sup>3.11</sup>P in a random collection of pennies using the isotope equation. Then, students discover that elements exist as isotopes and apply the isotope equation to actual isotopes. Click the image above to launch the lab.

. . . the discovery that there are two types of "Penny" that differ only in their weights allows the introduction of isotopes. In this lab, students determine the fraction of 2.5P and 3.11P in a random collection of pennies using the isotope equation. Then, students discover that elements exist as isotopes and apply the isotope equation to actual isotopes. Click the image above to launch the lab.
A virtual pre-lab activity where students record a series (1 - 12 determined by the instructor) of graduated cylinder readings. Click the image above to launch the lab.

. . . a virtual pre-lab activity where students record a series (1 - 12 determined by the instructor) of graduated cylinder readings. Click the image above to launch the lab.
A virtual pre-lab activity where students prepare a buret for use and make several buret readings. Click the image above to launch the lab.

. . . a virtual pre-lab activity where students prepare a buret for use and make several buret readings. Click the image above to launch the lab.
A virtual pre-lab activity where students record a series (1 - 12 determined by the instructor) of buret readings. Click the image above to launch the lab.

. . . a virtual pre-lab activity where students record a series (1 - 12 determined by the instructor) of buret readings. Click the image above to launch the lab.
A virtual pre-lab activity where students transfer 10.0 mL of liquid in a graduated pipette fitted with a suction bulb. Then, students record a series (1 - 12 determined by the instructor) of graduated pipette readings. Click the image above to launch the lab.

. . . a virtual pre-lab activity where students transfer 10.0 mL of liquid in a graduated pipette fitted with a suction bulb. Then, students record a series (1 - 12 determined by the instructor) of graduated pipette readings. Click the image above to launch the lab.
A virtual pre-lab activity where students explore the relationship between a liquid's kinetic energy and its thermal expansion. Then, students record a series (1 - 12 determined by the instructor) of temperature readings. Click the image above to launch the lab.

. . . a virtual pre-lab activity where students explore the relationship between a liquid's kinetic energy and its thermal expansion. Then, students record a series (1 - 12 determined by the instructor) of temperature readings. Click the image above to launch the lab.
A virtual pre-lab activity where students estimate and record the volumes displayed in a series of Erlenmeyer flasks. Click the image above to launch the lab.

. . . a virtual pre-lab activity where students estimate and record the volumes displayed in a series of Erlenmeyer flasks. Click the image above to launch the lab.
A virtual pre-lab activity where students are introduced to burets, buret clamps, Erlenmeyer flasks, volumetric pipettes, suction bulbs, and magnetic stir bars / plates. In the interactive part, students drag a pH slider that delivers titrant from the buret, displays an animated titration curve and shows the indicator's color change at its endpoint. Click the image above to launch the lab.

. . . a virtual pre-lab activity where students are introduced to burets, buret clamps, Erlenmeyer flasks, volumetric pipettes, suction bulbs, and magnetic stir bars / plates. In the interactive part, students drag a pH slider that delivers titrant from the buret, displays an animated titration curve and shows the indicator's color change at its endpoint. Click the image above to launch the lab.
A virtual pre-lab activity where students apply six solubility rules to randomly-generated ionic compounds. Click the image above to launch the lab.

. . . a virtual pre-lab activity where students apply six solubility rules to randomly-generated ionic compounds. Click the image above to launch the lab.
A virtual lab where students react Zn<sub>(s)</sub> and HCl<sub>(aq)</sub>. Students assemble a ring stand, ring clamp and wire gauze and evaporate the product mixture to obtain Zinc chloride. The molar ratios of Zn : Cl are used to determine the empirical formula of the product. Click the image above to launch the lab.

. . . a virtual lab where students react Zn(s) and HCl(aq). Students assemble a ring stand, ring clamp and wire gauze and evaporate the product mixture to obtain Zinc chloride. The molar ratios of Zn : Cl are used to determine the empirical formula of the product. Click the image above to launch the lab.
A virtual lab where students react CaCO<sub>3 (s)</sub> and HCl<sub>(aq)</sub>. Students assemble a ring stand, ring clamp and wire gauze and evaporate the product mixture to obtain CaCl<sub>2 (s)</sub>. The theoretical yield and percent yield are part of the lab calculations. Click the image above to launch the lab.

. . . a virtual lab where students react CaCO3 (s) and HCl(aq). Students assemble a ring stand, ring clamp and wire gauze and evaporate the product mixture to obtain CaCl2 (s). The theoretical yield and percent yield are part of the lab calculations. Click the image above to launch the lab.
Students record the mass and change in temperature of a virtual neutralization reaction. Next, they determine the limiting reagent and calculate the Heat of Neutralization. Click the image above to launch the lab.

. . . students record the mass and change in temperature of a virtual neutralization reaction. Next, they determine the limiting reagent and calculate the Heat of Neutralization. Click the image above to launch the lab.
Students use benzoic acid to calibrate a bomb calorimeter. Then, they burn a certain mass of Cheetos to determine the Heat of Combustion. Finally, they convert the Heat of Combustion to calories per serving and calculate a percent error. Click the image above to launch the lab.

. . . students use benzoic acid to calibrate a bomb calorimeter. Then, they burn a certain mass of Cheetos to determine the Heat of Combustion. Finally, they convert the Heat of Combustion to calories per serving and calculate a percent error. Click the image above to launch the lab.
Students use a color wheel to predict the absorbed color of several fruits. Then, our ability to see color is explained . . . the role of red, green and blue cone cells. Next, a virtual spectrometer is used to generate the absorbance spectrum of several food dyes. Finally, the absorbance values of a dilution profile are graphed to determine the concentration of Blue 1 dye in an unknown sample. Click the image above to launch the lab.

. . . students use a color wheel to predict the absorbed color of several fruits. Then, our ability to see color is explained . . . the role of red, green and blue cone cells. Next, a virtual spectrometer is used to generate the absorbance spectrum of several food dyes. Finally, the absorbance values of a dilution profile are graphed to determine the concentration of Blue 1 dye in an unknown sample. Click the image above to launch the lab.
Students learn about Newton's prism experiments, gas discharge tubes and using a spectroscope to separate light and measure its wavelength. Click the image above to launch the lab.

. . . students learn about Newton's prism experiments, gas discharge tubes and using a spectroscope to separate light and measure its wavelength. Click the image above to launch the lab.
First, students enter the molecule's total number of valence electrons. Next, students draw the Lewis structure. Then, students rotate three possible structures and choose the one with the correct 3D geometry. Finally, students enter the structure's electronic geometry, hybridization, molecular geometry and polarity. Click the image above to launch the lab.

. . . first, students enter the molecule's total number of valence electrons. Next, students draw the Lewis structure. Then, students rotate three possible structures and choose the one with the correct 3D geometry. Finally, students enter the structure's electronic geometry, hybridization, molecular geometry and polarity. Click the image above to launch the lab.
Students view the solute effect (number of ions and concentration) on freezing point depression, boiling point elevation, vapor pressure lowering and osmotic pressure. They also see the temperature effect on vapor pressure and osmotic pressure. Students calculate the molarity and molality of a solution, and the mole fraction of both solute and solvent of a solution. Finally, students determine the molar mass of a virtual unknown. Click the image above to launch the lab.

. . . Students view the solute effect (number of ions and concentration) on freezing point depression, boiling point elevation, vapor pressure lowering and osmotic pressure. They also see the temperature effect on vapor pressure and osmotic pressure. Students calculate the molarity and molality of a solution, and the mole fraction of both solute and solvent of a solution. Finally, students determine the molar mass of a virtual unknown. Click the image above to launch the lab.

Hybrid Labs - combine a virtual lab and a hands-on lab experiment . . . . they are performed in the student's kitchen. These labs are for distance-learning (college and home school) and for high school programs with limited equipment. Our goal is to provide a quality hands-on lab experience with "generally regarded as safe" chemicals, disposable reaction vessels, heating via microwave and oven, and replacing volumetric glassware by measuring the mass of liquid delivered. The virtual component contains virtual lab equipment (ironware, stirring hot plate, balance, chromatography chamber, buret, pressure gauge, etc.) and instruments (spectrometer, cathode ray tube, spectroscope, etc). This approach reduces cost while delivering quality learning experiences.
A virtual lab where students join the Hydrogen Shot team and explore how electrode materials and electrolysis solutions impact the splitting of water into hydrogen and oxygen. Click the image above to launch the lab.

. . . a virtual lab where students join the Hydrogen Shot team and explore how electrode materials and electrolysis solutions impact the splitting of water into hydrogen and oxygen. Click the image above to launch the lab.
Students determine the density of water, salt water and a post-2000 penny. In the virtual component, students determine the density of a metal cylinder to determine its elemental composition. In the final section, the length, width and density of Aluminum foil is used to calculate its thickness. Click the image above to launch the lab.

. . . students determine the density of water, salt water and a post-2000 penny. In the virtual component, students determine the density of a metal cylinder to determine its elemental composition. In the final section, the length, width and density of Aluminum foil is used to calculate its thickness. Click the image above to launch the lab.
Students virtually perform Lavoisier's 1774 Percent Oxygen in Air experiment. Then, students use activated steel wool and a 2L soda bottle to perform the Chem21 (21<sup>st</sup> century) version of this lab. Click the image above to launch the lab.

. . . students virtually perform Lavoisier's 1774 Percent Oxygen in Air experiment. Then, students use activated steel wool and a 2L soda bottle to perform the Chem21 (21st century) version of this lab. Click the image above to launch the lab.
Students determine the percent Hydrogen in water, percent of the components of a heterogenous mixture and the percent water in popcorn. Click the image above to launch the lab.

. . . students determine the percent Hydrogen in water, percent of the components of a heterogenous mixture and the percent water in popcorn. Click the image above to launch the lab.
Students heat a virtual colored hydrate that changes color when it loses its waters of hydration. Then, students determine the waters of hydration in Epsom salt using their kitchen oven. Click the image above to launch the lab.

. . . students heat a virtual colored hydrate that changes color when it loses its waters of hydration. Then, students determine the waters of hydration in Epsom salt using their kitchen oven. Click the image above to launch the lab.
Students perform a mix of hands-on and virtual chemical reactions of the following types: precipitation, acid-base, RedOx and decomposition. Click the image above to launch the lab.

. . . students perform a mix of hands-on and virtual chemical reactions of the following types: precipitation, acid-base, RedOx and decomposition. Click the image above to launch the lab.
Students hold six test tubes (blank, dilution profile and unknown) in front of a green computer screen and take a picture. The picture is uploaded into a color evaluator app that measures the intensity of the rgb colors used to display the picture on a computer monitor. A graph of the 'g' values provides a mathematical relationship between absorbance and concentration . . . . the unknown's absorbance value is used to find its concentration. Click the image above to launch the lab.

. . . students hold six test tubes (blank, dilution profile and unknown) in front of a green computer screen and take a picture. The picture is uploaded into a color evaluator app that measures the intensity of the rgb colors used to display the picture on a computer monitor. A graph of the 'g' values provides a mathematical relationship between absorbance and concentration . . . . the unknown's absorbance value is used to find its concentration. Click the image above to launch the lab.
In the hands-on lab, students determine the molar mass of Na<sub>2</sub>CO<sub>3</sub> from the mass of CO<sub>2</sub> lost in the Na<sub>2</sub>CO<sub>3</sub> + HC<sub>2</sub>H<sub>3</sub>O<sub>2</sub> reaction. In the virtual lab, the molar mass of NaHCO<sub>3</sub> is determined from the volume of CO<sub>2</sub> evolved in the NaHCO<sub>3</sub> + HC<sub>2</sub>H<sub>3</sub>O<sub>2</sub> reaction. Click the image above to launch the lab.

. . . in the hands-on lab, students determine the molar mass of Na2CO3 from the mass of CO2 lost in the Na2CO3 + HC2H3O2 reaction. In the virtual lab, the molar mass of NaHCO3 is determined from the volume of CO2 evolved in the NaHCO3 + HC2H3O2 reaction. Click the image above to launch the lab.
Students add hot water to the Styrofoam calorimeter containing cold water. The heat from the hot water enters the cold water and the calorimeter. The heat gained by the calorimeter divided by its temperature change is its heat capacity. Click the image above to launch the lab.

. . . students add hot water to the Styrofoam calorimeter containing cold water. The heat from the hot water enters the cold water and the calorimeter. The heat gained by the calorimeter divided by its temperature change is its heat capacity. Click the image above to launch the lab.
In the virtual lab, students determine the specific heat of an unknown metal so they can identify the metal. In the hands-on lab, students determine the specific heat of 10 pennies. Click the image above to launch the lab.

. . . in the virtual lab, students determine the specific heat of an unknown metal so they can identify the metal. In the hands-on lab, students determine the specific heat of 10 pennies. Click the image above to launch the lab.
Students determine the Heat of Fusion of Ice, first in a virtual lab and second in a hands-on lab. Click the image above to launch the lab.

. . . students determine the Heat of Fusion of Ice, first in a virtual lab and second in a hands-on lab. Click the image above to launch the lab.
In the virtual component, students observe the impact of pressure and temperature on the phases of matter, contruct a phase diagram, name the various phase changes, generate a heating curve, and calculate the heat absorbed when water transitions through a phase change. In the hands-on part, students calibrate their microwave oven's POWER and use this value to determine the Heat of Vaporization of water. Click the image above to launch the lab.

. . . in the virtual component, students observe the impact of pressure and temperature on the phases of matter, contruct a phase diagram, name the various phase changes, generate a heating curve, and calculate the heat absorbed when water transitions through a phase change. In the hands-on part, students calibrate their microwave oven's POWER and use this value to determine the Heat of Vaporization of water. Click the image above to launch the lab.
Students interact with an animated phase diagram to observe the vapor pressure lowering effect of added salt (NaCl) solution. As the vapor pressure is lowered, the freezing point is lowered and the boiling point is elevated. In the hands on component, students prepare a 4 m NaCl solution and compare its freezing point and boiling point to that of pure water. Click the image above to launch the lab.

. . . Students interact with an animated phase diagram to observe the vapor pressure lowering effect of added salt (NaCl) solution. As the vapor pressure is lowered, the freezing point is lowered and the boiling point is elevated. In the hands on component, students prepare a 4 m NaCl solution and compare its freezing point and boiling point to that of pure water. Click the image above to launch the lab.
A virtual stirring hot plate has been created but is not currently in a virtual lab. The plate's buttons work just like a real stirring hot plate. Click the image above to launch the animation - click/drag the stirring bar and flask to the plate . . . click/drag/rotate the two knobs.

. . . a virtual stirring hot plate has been created but is not currently in a virtual lab. The plate's buttons work just like a real stirring hot plate. Click the image above to launch the animation - click/drag the stirring bar and flask to the plate . . . click/drag/rotate the two knobs.


Hands-on Labs - along with the labs listed above, these labs are used by distance-learning students and are performed in the student's kitchen.
Students burn steel wool (98% Fe) to form iron oxide. The mass of product formed is used to determine its empirical formula. Click the image above to launch the lab.

. . . students burn steel wool (98% Fe) to form iron oxide. The mass of product formed is used to determine its empirical formula. Click the image above to launch the lab.
Students are presented with four possible decomposition reactions. For each reaction, they use the starting mass of NaHCO<sub>3</sub> to determine the theoretical yield of the sole solid product in each reaction. Then, students thermally decompose NaHCO<sub>3</sub> and weigh the solid product to determine which decomposition reaction actually occurred. Click the image above to launch the lab.

. . . students are presented with four possible decomposition reactions. For each reaction, they use the starting mass of NaHCO3 to determine the theoretical yield of the sole solid product in each reaction. Then, students thermally decompose NaHCO3 and weigh the solid product to determine which decomposition reaction actually occurred. Click the image above to launch the lab.
As Chem21 Certified Quality Technicians, students are hired by the makers of TUMS® to verify that their 1000 tablets contain 1000 mg of calcium carbonate. The mass of CaCO<sub>3</sub> is determined from the mass of CO<sub>2</sub> lost in the CaCO<sub>3</sub> + HC<sub>2</sub>H<sub>3</sub>O<sub>2</sub> reaction. Click the image above to launch the lab.

. . . as Chem21 Certified Quality Technicians, students are hired by the makers of TUMS® to verify that their 1000 tablets contain 1000 mg of calcium carbonate. The mass of CaCO3 is determined from the mass of CO2 lost in the CaCO3 + HC2H3O2 reaction. Click the image above to launch the lab.
Students use the endpoint of phenolphthalein to indicate the specific place in the titration when quantitative measurements gives the most accurate results. The reaction is performed in a disposable cup fitted with two binder clips, an HCl pipet (red ring) and a NaOH pipet (blue ring). Click the image above to launch the lab.

. . . students use the endpoint of phenolphthalein to indicate the specific place in the titration when quantitative measurements gives the most accurate results. The reaction is performed in a disposable cup fitted with two binder clips, an HCl pipet (red ring) and a NaOH pipet (blue ring). Click the image above to launch the lab.
Time-Repetitive Quizzes (TRQs) - have you struggled with how to help your students achieve deeper learning and understanding in General Chemistry and Organic Chemistry? The key is to build and maintain basic chemical knowledge that can form supportive connections to more complex processes. When this "building and maintaining" is managed by the student, the class is adversely affected in one of two ways:
  1. the pace slows to keep more students "progressing"
  2. the pace does not change and the DFW rate increases
TRQ assignments allow the instructor to manage the building and maintaining of basic chemical knowledge . . . and students receive course credit for "studying" . . . a WIN, WIN!! TRQs are designed so that the ONLY reason a student can give for not doing them is "I didn't want to." It is likely you have never (or rarely) heard this excuse from a student . . . . and you won't hear it for the TRQ assignment because more than 90% of students complete 100% of the assignments and receive 100% of the TRQ grade for the course. To learn more about TRQs, click here. To launch a demo TRQ and work through it as a student, click here.

After completing the "TRQ01 Elements 1-36" demo TRQ, click the Back To Assignment Menu link (bottom of page) to view a list of 45 other TRQs over General Chemistry topics that you can work (if you would like to view TRQs over Organic Chemistry, email support@chem21labs.com).

Your answers will not be saved after you log out - to set up a class where answers are saved, email support@chem21labs.com.

TRQs are fully customizable - you select the topic and questions that your students will see. There's also a "Super TRQ" that contains 100 of the most missed questions from multiple TRQ assignments . . . . each student sees 100 of their most missed questions.

Tutorials - click a tutorial assignment below to launch the demo version and work through it as a student. Students get as many tries as needed to complete the interactive tutorial . . . . an incorrect answer restarts the tutorial after feedback is given. The only grades available for a tutorial are 0 and full credit.
Students prepare a buret for a titration. Click the image above to launch the tutorial.

. . . students prepare a buret for a titration. Click the image above to launch the tutorial.

Homework - click a homework assignment below to launch the demo version and work through it as a student. Your answers will not be saved after you log out - to set up a class where answers are saved, email support@chem21labs.com.

. . . from balancing equations to interactive calculation guides to questions with randomly-generated numbers . . . Chem21Labs has it all. Click the image above to launch the assignment.
Organic structures are created on the Chem21Draw canvas and graded in real-time. Enhanced feedback is made possible with our proprietary grading code - mouseover graded answers for feedback (correct answers have a green background, incorrect answers have a red background). Click the image above to launch the assignment.

. . . organic structures are created on the Chem21Draw canvas and graded in real-time. Enhanced feedback is made possible with our proprietary grading code - mouseover graded answers for feedback (correct answers have a green background, incorrect answers have a red background). Click the image above to launch the assignment.

Google "online homework help sites" and you will find sites that . . .

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  • pay another person to work your homework problem(s).

Are you interested in . . .

  • saving students money spent on these "answer sites"?
  • increasing learning for all students?
  • decreasing test anxiety for all students?
  • decreasing DFW levels?
  • increasing enrollment in upper-division courses?

Chem21Labs has the answer . . . it's likely something you have not considered before, but the results are amazing when implemented as described. Click here to discover how to become a winning coach for Team Chemistry and give your students the skills to succeed at the next level.