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Thursday, Oct. 29th:

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Calorimetry and Hess s Law Procedure The procedure for this lab is a little confusing because the original lab handout showed 2 different ways of running the lab. – PowerPoint PPT presentation

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Title: Thursday, Oct. 29th:


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Friday, Nov. 2nd A DayMonday, Nov. 5th B
DayAgenda
  • Homework Questions/problems
  • Sec 10.4 Quiz Order and Spontaneity
  • Lab Discussion/write-up Calorimetry and
    Hesss Law
  • Movie Heat
  • Concept review work time
  • Lab next time dress appropriately!

3
Sec. 10.4 reviewPg. 367 3-5, 7-11
  • Questions?
  • Problems?
  • Hand in

4
Sec 10.4 QuizOrder and Spontaneity
  • You can use your notes, your book, and a lab
    partner of your choice to complete the quiz
  • Good Luck!
  • Pick up a copy of the lab when you hand in your
    quiz and start reading it through

5
Calorimetry and Hesss LawDiscussion
  • Remember, Hesss Law states that we can find the
    enthalpy change for a reaction by adding up the
    enthalpy changes for the individual steps.
  • You will run 3 different reactions
  • NaOH (s) H2O (l)
  • NaOH (aq) HCl (aq)
  • NaOH (s) HCl (aq)
  • (The 1st 2 reactions add up to give the 3rd)

6
Calorimetry and Hesss LawDiscussion
  • You will use the calorimetry equation
  • q mC?T to calculate the heat released in each
    reaction.
  • You will then use stoichiometry and the
    calorimetry equation to calculate find out if the
    temperature did indeed get hot enough to burn the
    man.

7
Calorimetry and Hesss LawPurpose
  • What is the purpose of this lab?
  • The purpose of this lab is to measure the amount
    of heat released by mixing NaOH and HCl to find
    out if enough heat is released to raise the
    temperature high enough to cause a burn.

8
Calorimetry and Hesss LawMaterials
  • There are a few changes to the materials list
  • We will NOT be using the 3 items listed under
    Optional Equipment
  • We will be using calorimeters, NOT plastic foam
    cups
  • You will use a porcelain scoop instead of forceps
    when handling the NaOH.
  • Changes to material list have already been made!

9
Calorimetry and Hesss LawProcedure
  • The procedure for this lab is a little confusing
    because the original lab handout showed 2
    different ways of running the lab.
  • Your procedure starts on the top of pg. 36 where
    it says Advance Preparation, steps 1 and 2.
  • The rest of page 36 is crossed out because you
    will be using the Thermometer Procedure that
    begins on pg. 39.

10
Lab Discussion Calorimetry and Hesss Law
  • There are 3 different reactions you will be
    running, all using hydrochloric acid (HCl) and
    sodium hydroxide (NaOH).
  • You do not have to wear gloves when handling the
    NaOH, but you must use the porcelain scoop to
    measure them. Do not touch the pellets!
  • Be sure to CLOSE the NaOH container when done
    measuring it because it is hygroscopic , meaning
    it will absorb moisture from the air and gain
    mass.

11
Lab Discussion Calorimetry and Hesss Law
  • When you add the chemicals to the calorimeter,
    make sure you add them to the beaker and NOT
    directly into the metal calorimeter container.
  • These chemicals are corrosive and will pit the
    metal calorimeters.
  • The actual laboratory part of this lab is not
    difficult, its the calculations that will take
    some time.
  • We will go through the calculations
  • together back in the classroom.

12
Lab Write-Up Calorimetry and Hesss Law
  • Be sure to update your table of contents with
    this lab.
  • You have the rest of the period to complete the
    lab write-up with your lab partner
  • Title
  • Purpose
  • Hypothesis
  • Materials
  • Procedure
  • Reflection Statement

13
Movie Heat
  • You DO NOT have to take
  • notes on the movie, but I do
  • expect you to pay attention!
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