Tag Archives: molarity

Toxins: Mystery Solutions

For class today, students will watch Life’s Rocky Start from NOVA.  While watching the video, students will complete a worksheet to help them identify the key learning from throughout the video.  The worksheet should be turned in at the end of class.

Update: May 10 – thank you to Mrs. C for substituting for me yesterday.  The students were in her capable hands and did a great job staying engaged through the video.  For today, students worked through the Lesson 83 Worksheet.  We approached Part 1 as a thought experiment and notes from the whiteboard are pictured below.  The Lesson 83 PowerPoint is included for reference.

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Toxins: Preparing Solutions

We took advantage of the gap in AP testing to work through Lesson 82.  The Lesson 82 Worksheet called for students to work in groups to prepare salt solutions and work through the math to calculate the molarity of their assigned solution.  Although we did not review it in class, the Lesson 82 PowerPoint is available for download.

Additionally, students are encouraged to practice observing the relationship between moles, volume, and molarity using the University of Colorado Molarity PhET simulation below:

https://phet.colorado.edu/sims/html/molarity/latest/molarity_en.html

Toxins: Molecular Views

Our work today involved thinking about solutions from a molecular perspective.  Students briefly reviewed yesterday’s Gummy Bear portion of the lab via the ChemCatalyst on slide 3 of the Lesson 81 PowerPoint.  Students then received the Lesson 81 Worksheet and the Particle Views Handout.  The handout was used in Part 1 of the worksheet.  For Part 2, students assembled into groups and gathered around lab stations to gain experience diluting a 3.0 M stock solution to a 1.5 M solution.  They also observed how two different volumes of a solution with the same concentration both appear the same color.  The lesson helped illustrate the connection between molarity (M), particle density, and the number of moles (particle number) in a solution.  Pictures from the white board are shown below.

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Toxins: Solution Concentration

For the first lesson of Chapter 15, students were immersed in the vocabulary of solution concentration.  The Lesson 80 PowerPoint includes five important vocabulary words that students recorded in their lab notebooks.  They then were shown gummy bears that had been placed overnight in either water, 0.1 M sugar, 1.0 M sugar, 2.0 M sugar, or honey.  The gummy bears were rinsed and the mass was measured.  The results are pictured below:

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Students briefly thought about why the gummy bears changed mass and used the data and their thinking to complete Part 2 of the Lesson 80 Worksheet.  Students then transitioned to lab stations, working in groups to complete part 1 of the worksheet.  Most groups had time to finish either the sugar or the salt portion of the lab before we reconvened as a group to share results.  While students were settling in, they were treated to a chemistry video showing what happens when a bit of salt is added to a supersaturated salt solution.

Results from the lab are shown below.  Students should calculate the final column as homework.

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