Thermal Equilibrium (In Person)

Edit Experiment

VIDEO LINKS:

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

  1. Enthalpy of Fusion of Ice
  2. Specific Heat of Ice

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

  1. Calorimetry for Phase Transitions

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

  1. (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.
  2. (Acquiring competencies) Follow the change in temperature until the ice is fully melted and the temperature doesn\'t go down any further. If this takes more than 15 minutes or the temperature goes below 4 ºC, start the experiment again with more water. You are encouraged to record your temperature values at specific time intervals (ex. every minute) to keep track of the amount of time that elapsed from the moment you put the ice in the water and the moment thermal equilibrium was established.
  3. (Representation) Prepare a table for the data in experiment 1 showing the temperature after each minute. At 0 minutes it will have the temperature of the DI water in the cup.
  4. (Representation) Prepare a table for the data in experiment 2 showing the temperature after each minute. At 0 minutes it will have the temperature of the DI water in the cup.

Data Processing

  1. (Analysis) Looking at your data for experiment 1, identify the temperature at thermal equilibrium, which is the final temperature of your combined water and melted ice.
  2. (Representation) On a piece of paper, draw a large heating curve for water in black ink. Label the y-axis as temperature, and the x-axis as heat added. Mark the freezing and boiling points for water on the temperature axis. The graph will look like a series of steps.
  3. (Representation) Label each slanted line in black ink with the appropriate expression for finding the heat absorbed or released during a temperature change. Please, include the state of the substance for which the specific heat constant is used.
  4. (Representation) For the horizontal lines, indicate the connected phases in black ink. Then, label each horizontal line with the expression for the heat evolved or absorbed in that phase change. Include any constants that are used.
  5. (Representation) Mark the changes that the cooling of the water underwent in blue and the changes the ice underwent in red. They should meet in one point on the graph.
  6. (Manipulation) Using your recorded mass for the water, initial and final temperatures for the water and the specific heat of water, calculate the heat released by the water.
  7. (Manipulation) Using your calculated heat released by the water, find the amount of heat absorbed by the ice.
  8. (Manipulation) Using your calculated heat absorbed by the ice, mass of ice and assuming that the melting ice was at 0ºC, calculate the enthalpy of fusion of ice.
  9. (Analysis) Looking at your data for experiment 2, identify the temperature at thermal equilibrium, which is the final temperature of your combined water and melted ice.
  10. (Representation) On a piece of paper, draw a large heating curve for water in black ink. Label the y-axis as temperature, and the x-axis as heat added. Mark the freezing and boiling points for water on the temperature axis. The graph will look like a series of steps.
  11. (Representation) Label each slanted line in black ink with the appropriate expression for finding the heat absorbed or released during a temperature change. Please include the state of the substance for which the specific heat constant is used.
  12. (Representation) For the horizontal lines, indicate the connected phases in black ink. Then, label each horizontal line with the expression for the heat evolved or absorbed in that phase change. Include any constants that are used.
  13. (Representation) Mark the changes that the cooling of the water underwent in blue and the changes the ice underwent in red. They should meet in one point on the graph.
  14. (Manipulation) Using your recorded mass for the water, initial and final temperatures for the water and the specific heat of water, calculate the heat released by the water.
  15. (Manipulation) Using your calculated heat released by the water, find the amount of heat absorbed by the ice.
  16. (Manipulation) Using your calculated heat absorbed by the ice and the mass of the ice, assuming that the ice was originally at your freezer’s temperature, the melting point of ice is 0ºC, and the enthalpy of fusion is 6.01 kJ/mol, calculate the specific heat of ice
  17. (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 ...
Ice melts at 0.0°C. Freeze the water in the freezer and record the temperature when it melts.
Ice from distilled water and tap water will have the same melting point.

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. (Existing knowledge, research, and views) Define thermal equilibrium.
  2. (Acquiring competencies) Describe how a coffee cup calorimeter was used to study thermal equilibrium.
  3. (Acquiring competencies) Describe at least 3 properties of Styrofoam cups that make them suitable for these experiments.
  4. (Representation and interpretation) Write the formula for calculating heat using specific heat and interpret what it means.
  5. (Representation and interpretation) Write the formula for calculating heat using the enthalpy of fusion and interpret what it means.
  6. (Representation and interpretation) Write the formula for the mathematical expression describing thermal equilibrium between the system and the calorimeter and interpret what it means.
  7. (Analysis) Compare your value for the enthalpy of fusion to the values of the other groups in the class. Evaluate the precision of your measurement.
  8. (Analysis) Compare your value for the enthalpy of fusion to the literature value of 6.01 kJ/mol. Evaluate the accuracy of your measurement.
  9. (Analysis) Compare your value for the specific heat of ice to the values of the other groups in the class. Evaluate the precision of your measurement.
  10. (Analysis) Compare your value for the specific heat of ice to the literature value of 2.108 J/(g׺C). Evaluate the accuracy of your measurement.
  11. (Assumptions and limitations) Describe at least one assumption that you made about the ice cube in experiment 1. Evaluate how the final temperature of the cold water would be affected if your assumption is not valid.
  12. (Analysis) Provide at least one reason why we had to wait for the temperature to remain constant before terminating each experiment. Evaluate how not waiting would affect the values for the enthalpy of fusion and the specific heat for ice.
  13. (Analysis) Would you expect the calculated values for the enthalpy of fusion and the specific heat of ice to change, if you started the experiment with colder or warmer water in the cup? Provide at least one reason for your choice.