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April 2026 newsletter šŸŒ: new problem types for APĀ® Chemistry, webinar 4/22, and more!

A photo of Chris Carman, a 51-year old white man wearing a green t-shirt and holding a yellow book titled "Barron's AP Computer Science A 13th Edition"

Hello again! In this April-Fools-free newsletter, I’ve included the following important updates about ChemQuiz.net:

  • *NEW* problem types for APĀ® Chemistry: bond enthalpies, pH from strong acids & bases, and Le ChĆ¢telier’s principle!
  • Webinar about new problem types and more on Wednesday, April 22nd at 7pm ET/4pm PT
  • LOTS of bug fixes and other improvements
  • Site license renewal invoices for the ChemQuiz.net Dashboard for the 2026-2027 school year
  • The AP Computer Science A book I revised this past summer is out! šŸ˜±

*NEW* problem types for APĀ® Chemistry!

We’ve hit crunch time for APĀ® Chemistry*, so recently I’ve focused on adding question types to fill in some of the gaps on ChemQuiz.net before the exam in May. Here’s what’s new:

Enthalpy Calculations Quiz

For Topic 6.7: Bond Enthalpies, I added bond enthalpy questions with molecule diagrams like this:

A screenshot from the Enthalpy Calculations Quiz on ChemQuiz.net shows two example problems for calculating bond enthalpy values: "What is the enthalpy change (āˆ†H) in kJ/mol for orthosilicic acid when its bonds are formed? The bond enthalpy values are: D(Si-O) = 368 kJ/mol; D(O-H) = 467 kJ/mol" and "What is the enthalpy of reaction (āˆ†Hrxn) in kJ/mol for this reaction? The bond enthalpy values are D(N#N) = 945 kJ/mol; D(O=O) = 498 kJ/mol"

Chemical Equilibrium Quiz

I also spent a lot of time adding four new reaction direction and progress problem types for Topic 7.5: Magnitude of the Equilibrium Constant and Topic 7.7: Calculating Equilibrium Concentrations:

  • Determine reaction direction when given values of Kc and Kp

A screenshot from the Chemical Equilibrium Quiz on ChemQuiz.net shows an example reaction direction problem that reads: "HBr(g) -> H2(g) + Br2(g) Which reaction direction will be favored if the equilibrium constant (Kc) at 727Ā°C is 2.63 Ɨ 10^-5?"

  • Determine reaction direction when calculating values of Kc and Kp

A screenshot from the Chemical Equilibrium Quiz on ChemQuiz.net shows an example reaction direction problem that reads: "2 NO(g) + Cl2(g) -> 2 NOCl(g) NO reacts with Cl2 in a 4 L tank to form NOCl. At equilibrium, it is found that [NO] = 0.00275 M, [Cl2] = 0.0540 M, and [NOCl] = 0.137 M. Will products or reactants be favored by this system at equilibrium?"

  • Determine reaction progress when given values of Q and Kc or Kp

A screenshot from the Chemical Equilibrium Quiz on ChemQuiz.net shows an example reaction direction problem that reads: "CoO(s) + H2(g) -> Co(s) + H2O(g) The equilibrium constant (Kc) for this reaction is 67.0. If initial conditions produce a reaction quotient (Q) of 56.8, in which direction will this reaction proceed?"

  • Determine reaction progress when calculating values of Q and Kc or Kp

A screenshot from the Chemical Equilibrium Quiz on ChemQuiz.net shows an example reaction direction problem that reads: "Cl2O(g) + H2O(g) -> 2 HOCl(g) Cl2O reacts with H2O in a 0.05 L tank at 298Ā°C to form HOCl. It is found that (Cl2O) = 4.20 atm, (H2O) = 5.99 atm, and (HOCl) = 0.0190 atm. If Kp = 0.0900 at 298Ā°C, in which direction will the reaction proceed?"

I also added questions for Topic 7.9: Introduction to Le ChĆ¢telier’s Principle & Topic 7.10: Reaction Quotient and Le ChĆ¢telier’s Principle:

  • Predict shift in direction of reaction due to qualitative stresses (e.g., change in T, P, V, etc.)

A screenshot from the Chemical Equilibrium Quiz on ChemQuiz.net shows an example Le Chatelier's Principle problem that reads: "Consider the following reaction: 2 NaNO3(aq) + H2SO4(l) Na2SO4(s) + 2 HNO3(l) āˆ†HĀ° = 16.43 KJ The equilibrium constant (Kc) for this reaction is 0.140. What will happen to Kc if the temperature is decreased, and why?"A screenshot from the Chemical Equilibrium Quiz on ChemQuiz.net shows an example Le Chatelier's Principle problem that reads: "Consider the following reaction: Fe2O3(s) + 3 CO(g) 2 Fe(s) + 3 CO2(g) The system is at equilibrium when the amount of Fe2O3(s) is increased. If all other physical properties of the system remain constant, in which direction will the reaction be shifted as a result of this change?"A screenshot from the Chemical Equilibrium Quiz on ChemQuiz.net shows an example Le Chatelier's Principle problem that reads: "Given the following reaction: 2 H2(g) + CO(g) CH3OH(g) āˆ†HĀ° = 128.49 kJ Which change would result in shifting the reaction left toward the reactants?" and shows four multiple choice options: decrease the total pressure of the system, increase the concentration of CO, increase the temperature of the system, increase the total pressure of the system

pH & pOH Calculations Quiz

Finally, I added problems for Topic 8.2: pH and pOH of Strong Acids and Bases:

A screenshot from the Chemical Equilibrium Quiz on ChemQuiz.net shows two example pH calculation problem that read: "A solution of perchloric acid (HClO4) is measured to have a pH of 1.06. What is the concentration of this solution in M?" and "The concentration of a hydrobromic acid (HBr) solution is 7.66 Ɨ 10^-5 M. What is the pH of this solution?"

A screenshot from the Chemical Equilibrium Quiz on ChemQuiz.net shows two example pOH calculation problem that read: "A solution of lithium hydroxide (LiOH) is prepared so that its pOH is 3.87. What is the concentration in M of this basic solution?" and "What is the pOH of a basic sodium hydroxide (NaOH) solution if its concentration is 2.29 Ɨ 10^-5 M?"

I hope these new problem types are helpful for you and your students! If you come across any issues while using the new problem types, or if you have any suggestions for adding other topics or making improvements, please let me know!

* APĀ® is a registered trademark of College Board which is not affiliated with and does not endorse ChemQuiz.net. (FYI I’m required to include that language whenever I refer to APĀ® Chemistry.šŸ˜…)

Webinar Wednesday, April 22nd @ 7pm ET/4pm PT

I’ve really enjoyed talking to chemistry teachers from all over the world on the ChemQuiz.net webinars this school year! Everyone has been so nice, and I’ve received so many great questions, helpful suggestions and useful bug reports that I’m glad that I started hosting these.

The next live webinar will take place on Wednesday, April 22nd šŸŒ at 7pm Eastern Time/4pm Pacific Time on Zoom! This time, I’m going to focus on how to use the new APĀ® Chemistry problem types, and there’ll be time for a Q&A session at the end.

Please use this link to register for the webinar in advance:

https://us06web.zoom.us/meeting/register/070eGlvsSraQUVaYoQb3Bw

After registering, you should receive a confirmation email containing information about joining the meeting. If you have any topics youā€™d like me to add or any questions youā€™d like to submit in advance, please submit them using the Contact form or you can email me at chris@chemquiz.net.

I’ll also be sending out a “Certificate of Attendance” for one contact hour for everyone who attends so that you can use it for your teaching license renewal (or however your state does it). Iā€™m looking forward to seeing you there!

LOTS of bug fixes & other improvements

In addition to the new features listed above, I also fixed all of the following bugs and added some new features on ChemQuiz.net:

Dashboard ā€“ these also apply to PhysQuiz.net!

  • enhancement: changed the custom assignment name in the student view so that it’s bold and larger than the quiz name (thanks, Jason!)
  • bug fix: student names & IDs weren’t being included in results csv export (againšŸ¤¦šŸ»ā€ā™‚ļø) (thanks, Barbara and Lan!)

Question Banks ā€“ these also apply to PhysQuiz.net!

  • bug fix: pop-out options were only showing up when a new Question Banks assignment was edited but not when it was created

All Quizzes

  • bug fix: discovered that confetti wouldn’t work if Windows 11 accessibility setting for “Reduce motion” was activated (thanks, Katie!)

Most Quizzes ā€“ these also apply to PhysQuiz.net!

  • enhancement: pop-out calculator display now resizes if the number gets too long
  • bug fix: log function on pop-out calculator was returning “NaN” for every value (thanks, Heidi!)
  • bug fix: pop-out calculator would incorrectly display very small numbers (e.g., 6.626×10-34) as “0” (thanks, Ryan!)

Acid-Base Neutralization Quiz

  • enhancement: added “Display substances” option (thanks, Mary Jo!)

Balancing, Identifying & Predicting Chemical Equations Quiz

  • bug fix: incorrect product names were being displayed on “predicting” problems in presentation mode
  • bug fix: correct predicting answers were being marked as incorrect if they were chemical names and they were in a different order than the key

Bond Polarity & Electronegativity Quiz

  • new feature: improved answer explanations (thanks, Savannah!)

Chemical Equilibrium Quiz

  • new feature: added questions to compare current conditions/Q to given Keq value and have students choose reaction progress (thanks, Susan!)
  • new feature: added Le ChĆ¢telier’s Principle problems (thanks Trevor, Shelley and Emanuel!)
  • new feature: added “explain the relationship between values of Keq and relative concentrations at equilibrium” questions

Chemical Thermodynamics Quiz

  • bug fix: quiz was using thermodynamic values for diamond instead of regular elemental carbon (thanks, Susan!)

Electrochemistry Quiz

  • bug fix: electrolysis problems weren’t taking into account the coefficient of the elemental metal in calculations (thanks again, Susan!)

Elements & Isotopes Quiz

  • bug fix: quiz was consistently generating multiple choice options with no correct answer when “reduce multiple choice” options was being used with some question types (thanks, Chris!)
  • bug fix: quiz could sometimes generate blank multiple choice options for “Element name” and “Element symbol” question types

Enthalpy Calculations Quiz

  • new feature: added bond enthalpy questions with molecule diagrams šŸ¤©
  • bug fix: necessary values for physical and chemical change problems weren’t being passed to the answer page, so the quiz would give blank answers or crash (thanks, FS!)
  • bug fix: test code was showing up on the answer page (thanks again, FS!)

Gas Laws Quiz

  • bug fix: commas in student responses were causing them to be graded incorrectly (thanks, Pamela!)

Intermolecular Forces Quiz

  • correction: removed boric acid because it was confusing students (thanks, Keith!)

Molecular Geometry & VSEPR Quiz

  • bug fix: selecting all three options for “Electron domains” would crash the quiz (thanks, Jess!)

Naming Compounds & Calculating Molar Masses Quiz

  • correction: beryllium oxide was classified as “molecular” in the database, so the naming explanation was incorrect (thanks, Ashley!)

pH & pOH Calculations Quiz

  • new feature: added “calculate pH from hydroxide concentration” problems (thanks, Katie!)
  • new feature: added “calculate pH from strong acid & base molarity” problems
  • enhancement: added “Display substances as” option (thanks, Mary Jo!)
  • enhancement: improved variety of word problems

Stoichiometry & Limiting Reagents Quiz

  • bug fix: correct answer was not being displayed when student answer for limiting reagent problems was incorrect (thanks, Dorothy!)
  • bug fix: sig figs rounding was using excess reagent values and ignoring actual yield values with some limiting reagent problems (thanks again, Dorothy!)

Other improvements

  • bug fix: students were sometimes getting a “Request Entity Too Large” error when they tried to log in (thanks, Ashley!)

Thanks as always to everyone who has reported a bug or sent in a suggestion! It helps me more than I could sufficiently explain. If you come across any issues or errors while using ChemQuiz.net, please fill out this short Contact form and I’ll try to get it fixed as fast as I can.

* Advanced options are only available to teachers with an active site license for the ChemQuiz.net Dashboard

Site license renewals for the ChemQuiz.net Dashboard for the 2026-2027 school year

Thanks to everyone who has already purchased or renewed their site license for the ChemQuiz.net Dashboard for the 2026-2027 school year! Site licenses help me pay for web hosting, security software, and the software I use to write the quizzes and add new features. It also keeps the website ad-free ā€“ I can’t stand web ads, especially on education sites.

In the next few days, I’ll start sending out renewal invoices for the upcoming 2026-2027 school year. If you purchased your site license through Square, I’ll send out the renewal through their site, which sometimes goes to school “Spam” folders, so please keep an eye out for it. Otherwise, I’ll send you a traditional PDF attachment. If you’d like to change your payment method (e.g., use a school purchase order instead of paying out of pocket), please let me know and I’ll be happy to generate an invoice or sales quote for whatever payment method you’d prefer!

The benefits of having an active site license for the ChemQuiz.net Dashboard include the ability to:

  • create assignments for your students using the quizzes on the site
  • select the options you want that best match your students’ needs, including advanced options such as requiring correct sig figs in answers
  • allow your students to save their progress as they’re working on an assignment
  • build exams from multiple assignments
  • create custom question banks and flashcards with your own questions and images or use questions shared by the ChemQuiz.net educator community
  • use the “tab switch detection” anti-cheating feature
  • review results with your students so they can correct misconceptions and grasp concepts more quickly
  • track your students’ progress and download results for data analysis
  • create custom rubrics to score assignments
  • create timed assignments to help students prepare for state and APĀ® tests
  • choose from hundreds of “exemplar” assignments that are ready to use in your classes, including over 160 exemplars aligned to APĀ® Chemistry Learning Objectives
  • provide accommodations and modifications on assignments for students with special needs

If you’d like to purchase a 12-month site license for just US$99, you can do so in any of the following ways:

  • credit card through Square (the most popular option)
  • school purchase order (contact me for a sales quote!)
  • CashApp, PayPal, or Venmo at chris@chemquiz.net or @ChemQuizDotNet

Additional schools in the same district can purchase an add-on license for 50% off at just US$49 per school.

If your school offers physics, you can also bundle a site license for the PhysQuiz.net Dashboard for just US$49 more!

Site licenses also make it possible for me to make the ChemQuiz.net Dashboard free for the 232 U.S. public schools whose students are economically disadvantaged. If you teach in a high poverty public school in the United States (at least 50% of your students are on free/reduced lunch or designated “economically disadvantaged”), just send me a link to the supporting documentation and you’ll get a free site license for the ChemQuiz.net Dashboard foreverĀ ā€“Ā PhysQuiz.net, too!

Help me share ChemQuiz.net with the world!

If you like using ChemQuiz.net, there are three quick and easy things that you can do to help me promote the site!

  • Add your school to the long list of supporters on the About ChemQuiz.net page! Simply go to the ChemQuiz.net Dashboard, click on ā€œYour Infoā€ in the top menu bar, activate the box next to ā€œDisplay School on ChemQuiz.netā€œ, and click the ā€œUpdate Your Infoā€ button.
  • Tell another Chemistry teacher about ChemQuiz.net and encourage them to try out the Dashboard!
  • Follow @ChemQuizDotNet on BlueSky šŸ¦‹ and share my updates with your fellow Chemistry teachers!

The AP Computer Science A book I revised this past summer is out! šŸ˜±

A photo of Chris Carman, a 51-year old white man wearing a green t-shirt and holding a yellow book titled "Barron's AP Computer Science A 13th Edition"

As I mentioned back in the August 2025 newsletter, I was hired by Kaplan Publishing to revise the 13th Edition of Barron’s AP Computer Science A study guide this past summer, which I worked on nearly every day for over a month and a half. The book came out a few weeks ago, and I’m super excited to finally see it in print! It was a great book to begin with, and I learned a lot from the entire experience. Plus, everyone I worked with at Barron’s was so nice and helpful (and I promise that they’re not paying me to say that because I was just a revising author so I don’t get a cut of sales or anything like that)! šŸ˜‚ If you have a student or family member who’s preparing for the AP CS A exam, I humbly recommend checking it out!

Thanks so much for your continued support of ChemQuiz.net! Please feel free to contact me at any time by using the Contact form or emailing me at chris@chemquiz.net if you ever have any questions, comments, or concerns. For those of you in North America, I hope the last few months of the school year go smoothly for you and your students, and for everyone down under, I hope you’re off to a great start so far!

-Chris