Energy Learning Community

Lesson 2 - Thermochemistry

Lesson Plan

Grade Level:

High School (10th grade)

State Standards:

I. Content Standards
6.4 Describe the law of conservation of energy. Explain the difference between an endothermic process and an exothermic process.
II. Scientific Inquiry Skills Standards
SIS1. Make observations, raise questions, and formulate hypotheses.
SIS2. Design and conduct scientific investigations.
SIS3. Analyze and interpret results of scientific investigations.
SIS4. Communicate and apply the results of scientific investigations.
III. Mathematical Skills
Students should have the opportunity to apply:

  • Construct and use tables and graphs to interpret data sets.
  • Solve simple algebraic expressions
  • Measure with accuracy and precision (e.g., length, volume, mass, temperature, time)
  • Convert within a unit
  • Use common prefixes such as milli-, centi-, and kilo- .
  • Use scientific notation, where appropriate.
  • Determine the correct number of significant figures.
  • Determine percent error from experimental and accepted values.
  • Use appropriate metric/standard international (SI) units of measurement for mass (g); length (cm); and time (s).
  • Use the Celsius and Kelvin scales.
  •  

    Essential Questions:

    How is energy conserved in a chemical or a physical process?

    How can you determine the amount of energy absorbed or released in a chemical or physical process?

    Lesson Question:

    How can you calculate the heat of reaction when it cannot be directly measured?

    Introduction:

    Magnesium metal burns with a bright, extremely hot flame to produce magnesium oxide, as you have observed in the laboratory. Just to refresh your mind take a look at the video clip of this reaction below.

    Task:

    Using what we have learned so far in Thermochemistry, specifically your knowledge about enthalpy as state function, and the first law of thermodynamics you will measure the enthalpy for the reaction of magnesium metal and oxygen gas (from the air). The heat of reactions for magnesium metal and hydrochloric acid and magnesium oxide with hydrochloric acid are the two reactions you will use to accomplish this. Both are exothermic reactions that will allow you to measure their heat of reaction in a constant pressure calorimeter.

    Lesson Experiences:

    Watch this video "Combustion of Magnesium" by Dchummer on YouTube

    http://www.youtube.com/watch?v=Otx0jiwHFrw

    Then answer these warm-wp questions:
    What type of energy/energies do you think are present during the reaction?
    Can you measure any of them? If so how would you measure them?
    Would you have any safety concerns?

    Now you will be performing a lab. Note these pointers:
    · You will be working with your lab partner .
    · Follow the steps described in the "MgO Heat of Reaction Lab" (Word document under Resources). Please make sure to follow the laboratory safety procedures closely. I will be in the laboratory monitoring your progress and to collect the data sheet at the end of the lab.
    · You will have a choice to take photos of your experiment or videotape it for the lab report.
    · Once you have completed the hands-on section you will present your findings by writing a lab report. See link below.

    You will also present a summary of your work in a Prezi format in class. Your Prezi on Hess' Law should contain the following components:

    Lab Section

    % of Total Grade

    Purpose

    5

    Materials & Equipment (what would did you use to do the experiment)

    5

    Laboratory Safety

    5

    Video clip of procedure or pictures, and or a diagram

    15

    Heating Curve plot

    5

    Heat vs. Number of moles plot (optional)

    +5 extra credit

    Example of enthalpy of reaction
    calculation

    10

    Hess Law calculation to find enthalpy of reaction for MgO

    10

    Percent error

    5

    Lab Report

    40

    Total

    100%

     

    Finally, complete these steps for review:

    · Complete the Lesson Check as homework (See below)
    · Practice for the quiz on Hess' Law Online .

     

    Conclusion:

    The big idea of conservation of energy in a physical or chemical process should be very evident to students at the end of the lesson/lab. The heat flow can be measured between a system and surroundings. They have observed that energy in the form of heat can be released or absorbed, exothermic or endothermic. The heat flow at constant pressure can be measured using a "coffee cup" calorimeter, and that heat of reactions can also be measured using the known heats of reaction of two or more thermochemical equations or by using standard heats of formation.

    Assessments:

    The assessment of my students at this stage will include.
    · Lab Report (see rubric below, word document)
    · Oral Presentation Summary (Prezi)
    · Lesson Check (Quizlet)

    Quizlet

    Hess' Law Quiz (classmarker), with a 65% correctly answered is consider a passing grade.

    http://www.classmarker.com/


    Zumdahl, K; Chemistry; 5th Edition, Houghton Mifflin, 2000
    MCAS Chemistry 2011, DESE MA 2011

    All the students work will be assessed following Billerica Memorial High School Expectations for Learning rubrics, along with the specified grading rubric already stated above.

    Resources:

    1. Massachusetts Science and Technology/Engineering Curriculum Framework, October 2006

    Frameworks


    2. Definition of temperature and heat- Link
    http://youtu.be/vqDbMEdLiCs


    3. Link to Lecture notes in Thermochemistry (Word document & power point)

    Thermochemistry 2012-2013.docx

    CHAPTER 6 Thermodynamics.ppt


    4. "MgO Heat of Reaction Lab" (Word document)

    MgO Heat of Reaction Lab.docx


    5. Lab technique -Use of constant pressure calorimeter, and calculations

    http://www.youtube.com/watch?v=EAgbknIDKNo


    6. Plot heating curves

    Heating and Cooling curves

    by Savanna Roberts on 6 January 2012 on Prezi



    7. Hess' law and its conventions

    Enthalpies of Reaction and Hess's Law

    by Karishma Modha on 16 January 2012 on Prezi



    .
    8. Tutorial on Hess' Law Calculations
    http://www.gst-d2l.com/homework/Hess.html

    9. Billerica Memorial High School Learning Expectations 2012 , Standards A,B,D, & E(Word Document)

    Std A. Think Skills.docx

    Std. B.Learn.& Prob.solv..docx

    Standard D Comm..docx

    Std E. Technology.docx



    10 . Rubric for assessing the written lab report (Word document)

    RUBRIC FOR ASSESSING LAB REPORTS 2013-2014.docx


    11. Kotz & Treichel , Chemistry & Chemical Reactivity, Thomson Learning Inc., 2003

    12. Zumdahl, K; Chemistry; 5th Edition, Houghton Mifflin, 2000

    13. MCAS Chemistry 2011, DESE MA 2011

     

    Image Credits:

    Dancing Flames of burning charcoal in the dark, by Oscar, via Wikimedia Commons

    Photographic capture of a flame created by throwing flint sparks onto a small pile of magnesium shavings from a common emergency firestarter and pocketknife, by Hiroaki Nakamura, via Wikimedia Commons