### Notes:

The Equilibrium Calculations Concept Builder is an adjustable-size file that displays nicely on smart phones, on tablets such as the iPad, on Chromebooks, and on laptops and desktops. The size of the Concept Builder can be scaled to fit the device that it is displayed on. The compatibility with smart phones, iPads, other tablets, and Chromebooks make it a perfect tool for use in a 1:1 classroom.

### Teaching Ideas and Suggestions:

This Concept Builder is intended for use in the middle to latter stages of a learning cycle on the use of the equilibrium constant equation. The equilibrium constant equation relates the equilibrium concentrations of reactants and products to each other. Success on this Concept Builder requires that students be able to write the K equation and perform the required algebraic manipulations to solve for the unknown. Each Difficulty Level includes a balanced chemical equation for a reversible reaction and a 5-row table with one unknown in each row. The rows of the table are independent of each other. So in effect, each table is like solving five unique problems.

There are three difficulty levels in the Concept Builder - Apprentice, Master, and Wizard - differ in terms of teh sophistication of the chemical equation, There are coefficients of 1, 1, and 1 in the Apprentice Level. And there are coefficients of 1, 2, and 2 in the Master Level. And finally, there are coefficients of 1, 3, and 2 in the Wizard Level. The learner can check a calculation as many times as needed. But every miss is counted and a Health Report is displayed once the table has been completed. The formula for determining a Health Rating is shown on a separate page. Students can repeat the exercise as many times as needed to improve their grade above a minimum-required level.

This Concept Builder was intended as an in-class activity or as an assigned out-of-class activity for those classrooms subscribed to Task Tracker. After some lab work, some discussion of how to write an equilibrium expression, and some guided practice, allow students to try it for themselves. Teachers using the Concept Builder with their classes should preview the activity (or view the Questions in a separate file) in order to judge which difficulty levels would be most appropriate for their students.

### The Health Rating:

We leave it to the discretion of individual teachers as to what they wish to do with the Health rating information. We recognize that there will be some teachers who feel most comfortable with their students in simply requiring that a difficulty level be completed and  trophy be earned. Other teachers may wish to require completion of a difficulty level with a minimum Health rating. For instance, such teachers may require that each difficulty level be completed with a 70% or higher Health rating. Still other teachers may tie the Health rating into a grade or allow a homework pass for completing an activity that exceeds a 90% Health rating. Decisions as to what to do with the Health rating are best left for individual teachers who know their students the best.

### Getting Help:

The most valuable (and most overlooked) aspect of this Concept Builder is the Help Me! feature. Each question group is accompanied by a Help page that discusses the specifics of the question. This Help feature transforms the activity from a question-answering activity into a concept-building activity. The student who takes the time to use the Help pages can be transformed from a guesser to a learner and from an unsure student to a confident student. The "meat and potatoes" of the Help pages are in the sections titled "How to Think About This Situation:" Students need to be encouraged by teachers to use the Help Me! button and to read this section of the page. A student that takes time to reflect upon how they are answering the question and how an expert would think about the situation can transform their naivete into expertise.

### Related Resources

There are numerous resources at The Physics Classroom website that serve as very complementary supports for the Impulse-Momentum Change Table Concept Builder. These include:

• Minds On Physics Internet Modules:
The Minds On Physics Internet Modules include a collection of interactive questioning modules that help learners assess their understanding of physics concepts and solidify those understandings by answering questions that require higher-order thinking. Missions MC2, MC3, and MC4 from the Momentum and Collisions module make for a great complement to this Concept Builder. They are best used in the middle to later stages of the learning cycle. Visit the Minds On Physics Internet Modules.

Users may find that the App version of Minds On Physics works best on their devices. The App Version can be found at the Minds On Physics the App section of our website. The Momentum and Collisions module can be found on Part 3 of the six-part App series. Visit Minds On Physics the App.

• Curriculum/Practice: Several Concept Development worksheets at the Curriculum Corner will be very useful in assisting students in cultivating their understanding, most notably ...

Momentum, Impulse and Momentum Change
Controlling a Collision
Simple Computation with Impulse = Momentum Change

Visit the Curriculum Corner - Momentum.

Additional resources and ideas for incorporating the Impulse-Momentum Change Table Concept Builder into an instructional unit on Momentum and Collisions  can be found at the Teacher Toolkits section of The Physics Classroom website.  Visit Teacher Toolkits.