Monday, Nov. 4 th : “A” Day Tuesday, Nov. 5 th : “B” Day Agenda

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Monday, Nov. 4 th : A Day Tuesday, Nov. 5 th : B Day Agenda. Check lab write-ups Lab Discussion/Safety Items Conduct lab and begin calculations: Calorimetry and Hesss Law Homework: Concept Review We will finish the lab calculations next time and the lab will be due. - PowerPoint PPT Presentation

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  • Monday, Nov. 4th: A Day Tuesday, Nov. 5th: B DayAgendaCheck lab write-upsLab Discussion/Safety ItemsConduct lab and begin calculations: Calorimetry and Hesss Law

    Homework: Concept ReviewWe will finish the lab calculations next time and the lab will be due

  • Calorimetry and Hesss LawDiscussionThere are 3 different reactions you will be running, all using hydrochloric acid (HCl) and sodium hydroxide (NaOH).Be sure to CLOSE the NaOH container when done using it because it is hygroscopic, meaning it will absorb moisture from the air and gain mass.Make sure to use the glass beaker inside the metal calorimeter DO NOT pour the acids and bases directly into the metal calorimeter they are corrosive and will damage (pit) the calorimeter!

  • Calorimetry and Hesss Law Safety IssuesYou do not have to wear gloves when handling the NaOH, but you must use the porcelain scoop. Do not touch the pellets!

    HCl is hydrochloric acid be careful when handling it.Make sure you are using the correct solution; there are 3 different solutions used in this lab.READ THE LABELS!

  • Calorimetry and Hesss LawRinse off the thermometer probe and stirring rod thoroughly with distilled water each time after recording the temperatures. DO NOT touch the metal probe until its been rinsed off.

    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

  • Calorimetry and Hesss Law In the Analysis section: you need to complete #1-#4 TODAY!

    Follow all directions carefully and have

  • Lab: Calorimetry and Hesss LawAnalysis1. Organizing DataWrite a balanced chemical equation for each of the 3 reactions.#1: NaOH(s) + H2O(l) NaOH(aq) + H2O(l)

    #2: HCl(aq) + NaOH(aq) NaCl(aq) + H2O(l)

    #3: HCl(aq) + NaOH(s) NaCl(aq) + H2O(l)

  • Lab: Calorimetry and Hesss Law2. Analyzing ResultsAdd the first 2 equations from question #1 to get the equation for reaction #3:

    #1: NaOH(s) + H2O(l) NaOH(aq) + H2O(l) + #2: HCl (aq) + NaOH(aq) NaCl(aq) + H2O(l)

    #3 NaOH(s) + HCl(aq) NaCl(aq) + H2O(l)

  • Lab: Calorimetry and Hesss Law3. Explaining EventsWhy does a plastic-foam cup make a better calorimeter than a paper cup?

    A good calorimeter must insulate and not transfer (lose) heat. Plastic-foam cups are better insulators than paper cups and therefore make a better calorimeter.

  • Lab: Calorimetry and Hesss Law4. Organizing DataCalculate the change in temperature (T) for each of the reactions.T = Tfinal TinitialExample:T1 = 26.5C 21.5C = 5.0CT2 = T3 =

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