Final Review Lab #2- Thermochemistry, Nuclear, and Equilibrium

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Objective

Students will be able to explain various semester 2 concepts through performing a review lab where they mix solutes with solvents, measure changes in temperature, and answer review type questions.

Big Idea

When a solute is added to a solvent it can either be an exothermic reaction that feels hot or an endothermic reaction that feels cold.

Introduction

In this lesson students have a chance to review for their final exam while also performing a fun and engaging lab activity where they mix solutes with the solvent water and measure the changes in temperature.

  • Because this is a review activity it touches on several of the NGSS Performance Expectations including:
    • HS-PS1-4: Develop a model to illustrate that the release or absorption of energy from a chemical reaction system depends on the changes in total bond energy.
    • HS-PS1-6: Refine the design of a chemical system by specifying a change in conditions that would produce increased amounts of products at equilibrium.
    • HS-PS1-8:Develop models to illustrate the changes in the composition of the nucleus of the atom and the energy released during the process of fission, fusion, and radioactive decay.
  • This lesson aligns with NGSS Science and Engineering Practice 3: Planning and Carrying out Investigations because students are performing a lab. 

For this lab activity there are several materials needed.  I provide the following for each lab group:

  • container with ammonium chloride
  • container with calcium chloride
  • ziploc bag
  • bottle of water
  • stir stick
  • 10mL graduated cylinder
  • 50mL graduated cylinder
  • pH meter
  • 2 styrofoam cups and a lid
  • temperature probe (could also use a normal thermometer if you want and have them just record initial temp and then highest temperature that they see).

This is a picture of a lab setup.

Explain

5 minutes

I begin this lesson by passing out the review lab 2.

I then go over the general safety guidelines.  This includes how students should be cautious with the salts, wear safety goggles, and wash their hands if they get any substance on themselves.  I also explain to students how the two styrofoam cups are their calorimeter and how they will need to make sure to record the initial temperature and then the highest temperature that the solution reaches.

I then break students into cooperative groups, have them go to their assigned lab stations and start the lab.  For more details on how I use cooperative groups in my classroom see my reflection from Unit 1. 

Elaborate

90 minutes

In this section of the lesson students are performing their lab and recording their results on their review lab 2 paper.

As students are working I encourage them to work with their lab groups to answer the questions.  If they are stuck I have them try to find the answers by looking back at their notes first, before asking me for help.  This is a video of a group working together to figure out that the solute for the first solution is ammonium chloride. 

Additionally, as students work I walk around to make sure that they are doing the problems correctly.  

Students tend to have a difficult time with calculations of Molarity for #8 and Parts Per Million #9.  This is a video of me helping students with these problems. 

Students also have a hard time with #9 where they have to remember how to solve calorimetry problems.

As students complete their labs I have them turn them in to my basket.  I grade their labs for completion with a check if it complete or mostly complete (100%) check minus if it is missing several answers (75%), and check minus minus if it is missing at least a page worth of answers (50%).

For the most part students earn all of their points on this lab.  This is because they are working on them with their partners and I am walking around to make sure that they are having their questions answered.

This is an example of one student's completed lab. 

Evaluate

25 minutes

As students complete their labs I have them work on their final exam review  This is a paper which I give students after the unit 10 exam, so they have well over a week to complete on their own as homework, as well as when we have extra time at the end of class.  I have students turn in the final exam review at the final.  I have copies of the answer key for the review for students to check as they are working on the review and have questions.  

This is a copy of one student's final review.

Some of the concepts that students have a hard time with on the review include: 

  • Figuring out the energy per gram of a chip (Unit 6 question #7)
  • Using the ideal gas law (Unit 7 questions #10 and #12).
  • Reading solubility curves (Unit 8 question #6)
  • Mass percent with differentiating between solute, solvent, and solution (Unit 8 questions #8 and #9)
  • Finding Molarity when given grams of solution (Unit 8 question #14)