Methods, Experiment, and Conclusion

Hand Warmer Lab: Han Pham and Emily Machen

Part A/B Introduction to Calorimeter Conclusion:

In conclusion, the objective of the first part of this lab was to calibrate the calorimeter in order to conduct the second part of this lab. There was a length procedure that we had to go to in order to excel in achieving our goal for this part of the experiment. On another note, many of the people in my class including my partner and I messed up during this first part of the procedure. We lost a bunch of heat by simply forgetting to do one simple step while trying to calibrate our calorimeter. Yes, this can and will affect our percent error. However, we acknowledged our mistake and if we could do this lab over again I am sure we would conduct it more precisely so that our data, information, and calculations will run a lot more smoothly and have more accuracy than before. In the second part of our lab, we made sure to ensure that our understanding of the directions were much more clear so that we could have an accurate hypothesis in determining which set of chemicals we thought would potentially have a better chance of conducting heat and being the best hand warmer. My partner and I have a few questions, does the outcome of us not keeping all of our heat inside the calorimeter affect the outcome of our second lab? Does the size of the cups differentiate on the capacity or calibration of the substance you will be using?

Guided Inquiry and Design Conclusion

In conclusion, the objective of this lab was to design a hand warmer using the three solids that we had chosen to do (NaCl, LiCl, and Na2CO3). The purpose of this lab was to determine which one of the solid or solids would conduct the best heat for a hand warmer. The result was the LiCl and Na2CO3 would conduct the best heat for a hand warmer. Both LiCl and Na2CO3 was exothermic which mean the heat would be released rather than being absorbed. It better for a hand warmer to released heat and not absorbed the heat. NaCl was endothermic, which mean it would absorb the heat rather than release it. The substance for NaCl dissolved very quickly. The substance for LiCl dissolve quickly, but slower than NaCl. The last substance, Na2CO3 didn’t dissolve completely and it take the longest to dissolve compare to the other two substances. One of my group uncertainty is that for NaCl, we forgot to close the lid. Since the lid was not close, some of the heat might had been lost. Since the heat might have been lost, our number might have been different from the actual number. Two things that my partner and I learned was that an exothermic reaction is best for a hand warmer and the substance for Na2CO3 didn’t dissolve like the other two substances. One question my partner and I still have is how would this lab relate to real life experience?



METHODS Part A/B Introduction

Part A: Heat Capacity of Calorimeter

  1. First, you have to set up a calorimeter consisting of two nested/stacked styrofoam cups in a ring clamp that is attached to a support stand.

  2. Next, Place a magnetic stirrer, if available, below the calorimeter.

  3. Measure 100 mL of distilled water in a 100 mL graduated cylinder and transfer the water into the calorimeter.

  4. Add a magnetic stirring bar to the calorimeter and set it to spin slowly. DO NOT remove the stirring rod from the calorimeter.

  5. Be sure to measure the temperature of the hot water with the digital thermometer, record this onto your data table.

  6. Heat approximately 125 mL of distilled water to 60-70 degrees celsius in a 250 mL beaker.

  7. Using tongs measure 100.0 mL of the hot water into a 100 mL graduated cylinder.

  8. Once again, be sure to measure and record the temperature of the hot water.

  9. Immediately pour the hot water into the room temperature water in the calorimeter.

  10. Insert the thermometer and stir the water.

  11. Record the mixing temperature after 20 seconds.

  12. Empty the calorimeter and dry the inside.


Part B: Calorimetry Procedure

  1. Measure 100 mL of distilled water in a 100 mL graduated cylinder and transfer it to the calorimeter.

  2. Be sure to record the initial temperature of the water.

  3. Measure 5.00 g of anhydrous magnesium sulfate in a weighing dish.

  4. Put a magnetic stir bar into the calorimeter and slowly stir the water.

  5. Quickly add the 5.00 g of anhydrous magnesium sulfate to the calorimeter and insert the thermometer.

  6. Monitor the temperature and record the highest/lowest temperature reading.

METHODS Guided Inquiry and Design

Part A:

  1. Working in pairs, set up a calorimeter consisting of two nested cups in a ring clamp attached to a support stand.

  2. place a magnetic stirrer below the calorimeter, then lower the ring clamp until the bottom of the cup just sits on the surface of the magnetic stirrer.

  3. Measure 40 mL of water in a graduated cylinder and transfer the water into the calorimeter.

  4. Add a magnetic stirring bar to the colorimeter. and set the bar spinning slowly. Use a stirring rod if you do not have a magnetic stirrer. Do not remove the stirring rod/magnetic stirrer from the calorimeter.

  5. Measure and record the initial temperature of the water.

  6. Heat approximately 100 mL of distilled water to 70-80 degrees celsius in a beaker.

  7. Using tongs measure 100.0 mL of the hot water in a graduated cylinder.

  8. Measure and record the temperature of the hot water.

  9. Immediately pour the hot water into the room temperature water in the calorimeter.

  10. Insert the thermometer, and stir the water.

  11. Record the mixing temperature (Tmix) after 30 seconds.

  12. Empty the calorimeter and dry the inside.

Part B:

  1. Measure 40.0 ml of distilled water in a 100 mL graduated cylinder and transfer to the calorimeter

  2. Measure and record the initial temperature of the water

  3. Measure 10 grams of your substance into a weigh boat.

  4. Put a magnetic stir bar into the calorimeter and stir the water

  5. Quickly add the 10 grams of your substance to the calorimeter and insert a thermometer

  6. Monitor the temperature and record the highest or lowest temperature reading

    • REPEAT FOR ALL OF THE CHEMICALS USED in your set.