Thermochemistry

Edit Experiment

VIDEO LINKS:

Lab Experiments (Write protocols and perform experiments based on these):

Data analysis and calculations (Use these if you need help with your data and calculations)

  1. Thermochemistry concepts:
  2. Thermochemistry calculations:
  3. Crash course in enthalpy:
  4. Crash course in the second law of thermodynamics

The prelab must include Experimental Protocol, Chemical Table and Equipment Table.

The lab report requires all sections (including prelab sections) to be completed in one document.

Experimental Protocol

(Analysis) Watch the experiment videos.  Take notes on the protocol.  Stop the video and re-watch as necessary to acquire the details of the procedure.  Write out the protocol for each part of the experiment.  (It can be written in sequential steps.  Complete sentences are not necessary.)  This is the protocol you will follow, so be detailed.

Chemical Table

(Representation) Prepare your chemical table including the materials you will use in the experiment.  Here is a general template that you may use.
Chemical Name Chemical Formula Molar Mass (g/mol) Hazards Reference PPE
Sodium Chloride NaCl 58.5 Skin irritation https://fscimage.fishersci.com/msds/21105.htm  
           
           

Equipment Table

(Analysis) Identify the equipment (type AND size) needed for the experiment and include the name and an image of each.  Be sure to describe the equipment, how to use it, and why it is suitable for this use.
Equipment Name Equipment Picture Intended Purpose

Data Collection

(Acquiring competencies) Following your detailed protocol based on the videos, perform all the experiments. Record your observations and take pictures of your key steps in the process.  Your observations and images need to be incorporated in your data section and this section should be as detailed as possible as you will use this information to complete your discussion.

Data Processing

  1. (Existing knowledge, Research, and views) Identify the chemical formula of the compound in the Magic Cook pouch.
  2. (Existing knowledge, Research and views) Identify the equation used to calculate the heat absorbed in a heating process. Indicate the meaning of each variable and its appropriate units.
  3. (Existing knowledge, Research and views) Identify the equation used to calculate the heat absorbed in the process of evaporating water. Indicate the meaning of each variable and its appropriate units.
  4. (Manipulation) Based on the mass and the change in temperature of the water, calculate the heat absorbed by the water.
  5. (Representation) Write a balanced chemical equation for the reaction that occurs when the Magic Cook pouch is submerged in water.
  6. (Existing knowledge, Research and views) Identify the equation used to calculate the enthalpy of a reaction. Indicate the meaning of each variable and its appropriate units.
  7. (Manipulation) Calculate the heat of the reaction for the Magic Cook pouch.
  8. (Manipulation) Calculate the enthalpy change of the reaction for the Magic Cook pouch.
  9. (Manipulation) Assuming the change in free energy is zero at the boiling point of water, calculate the ΔS of the reaction.
  10. (Manipulation) Based on your values for the enthalpy and entropy, calculate for the ΔG for your reaction at room temperature.
  11. (Interpretation) Evaluate your calculated ΔS and ΔG values. Based on the calculated values what can you say about the experiment?
  12. (Analysis) Compare the behavior of the pouch in the experiment with the predictions from question 11. Provide a supported argument for the similarities and differences.
  13. (Existing knowledge, research, and views) List the values for the enthalpy, entropy, and free energy for each compound in this reaction based on the published literature. Include your references.
  14. (Manipulation) Using the balanced chemical equation from question 6 and the literature values for each compound from question 13, calculate the enthalpy, entropy, and Gibbs-free energy of the reaction.
  15. (Manipulation) Collect the values of the enthalpy, entropy and free energy from your teammates’ experimental data. Calculate the % error comparing your average result for the enthalpy, entropy, and free energy in your experiment to the literature values.
  16. (Assumptions and Analysis) Fill in the following table using the observations and data from your experiments.
Assumptions made Testing the assumption If assumptions are wrong ...
All the mass of the Magic Cook pouch is MgO.  Perform the experiment with the same amount of MgO.  Compare the temperature.
 There is no heat lost to the environment from the Styrofoam cup.

Discussion

Write a minimum one-page (12 font, single spaced) discussion on the experiment conducted this week. Address at least one question in each category as fully as possible integrating the collected data, providing explanations for the observed trends, and evaluating whether your original assumptions about the experiment were validated by the results. The assignment will be graded on completeness, clarity of the explanations and the meaningful integration of the collected and calculated data. Correct grammar and appropriate format for the chemical formulae and chemical reactions is expected.
  1. (Mandatory question: analysis) Provide an explanation for how your original assumptions about the experiment were or were not validated by the results.
  2. (Existing knowledge, research, and views) Define temperature.
  3. (Existing knowledge, research, and views) Define heat.
  4. (Existing knowledge, research, and views) Define kinetic energy in a chemical system.
  5. (Existing knowledge, research, and views) Define potential energy of a chemical system.
  6. (Existing knowledge, research, and views) Define endothermic and exothermic reactions. Classify the reaction of the Magic Cook pouch with water as endothermic or exothermic.
  7. (Existing knowledge, research, and views) Define system and surroundings and then identify the system and surrounding for the experiment.
  8. (Analysis) Bubbles often indicate that a chemical reaction has occurred. List the source and cause of the bubbles you observed.
  9. (Experiment design) Propose a method you could use to identify the absence or presence of a chemical reaction.
  10. (Analysis) Provide at least one supported argument as to why the formation of the bubbles slows down and eventually stops.
  11. (Analysis) Give at least one supported argument to explain the use of an inner pouch rather than just the chemical.
  12. (Analysis) The Magic Cook pouch is packages in a sealed plastic bag. Provide a supported argument for why the packaging needs to be airtight.
  13. (Analysis) Predict what would happen if the Magic Cook pouch was fully submerged in methanol instead of water. Provide at least one supported argument for your prediction.
  14. (Analysis) The Magic Cook pouch is used to heat your drink in their specially designed cup. Draw a scheme showing the direction of the heat transfers.
  15. (Interpretation) Comment on the precision and accuracy of this experiment.
  16. (Analysis) List potential sources of error for this experiment and provide at least one supported argument for how each source of error impacts the enthalpy, entropy and the Gibbs-free energy of the reaction.
  17. (Existing knowledge, research and views) MRE (Meals Ready to Eat) use MgO rather than CaO. Look up the enthalpy, entropy and Gibbs-free energy of MgO and Mg(OH)2.
  18. (Representation) Write the balanced chemical equation for the reaction between MgO and water.
  19. (Interpretation) Describe the meaning of the chemical equation on the macroscopic and microscopic scale.
  20. (Manipulation) Using the balanced chemical equation from question 17 and the literature values for each compound from question 16, calculate the enthalpy, entropy, and Gibbs-free energy of the reaction between MgO and water.
  21. (Analysis) Evaluate whether the CaO or the MgO is more suitable for heating applications. Provide at least one supported argument for your choice.
  22. (Analysis) Predict the magnitude of the temperature change if we used 50 mL of water instead of the 100 mL amount. Provide a supported argument for your answer.
  23. (Analysis) Predict how the evolved heat, enthalpy, entropy and free energy would change, if a larger pouch was used. Provide a supported argument for each prediction.
  24. (Experiment design) Propose a protocol for testing the food or beverage heating capabilities of this product.
  25. (Existing knowledge, research and views) Magic Cook was introduced on Shark Tank. The “inventors” are accused of patent violation with Barocook. Please research this dispute and use a supported argument to comment on the ethics and validity of this claim.