Specific Heat Capacity Lab

Q = mcΔT

Procedure

  1. Turn on GLX. If it does not stay on it will need to remain plugged into an electrical outlet. Wait until you see the menu screen.
  2. Plug the Thermometer Probe into one of the two Temperature Probe inputs on the side of the GLX.
  3. Press the “Home” button and then the “Right Arrow” button in order to be on the “Digits” option. Then press the “Checkmark” button. (You should now see numbers)
  4. Mass a Styrofoam cup and record in Data Table 16-1.
  5. Fill the cup 1/3with room temperature tap water and mass it again. Record this new mass on Data Table 16-1.
  6. Compute the mass (mw)of the water in the cup. Record this on Data Table 16-1.
  7. Place the Temperature Probe into the water. Be sure it is completely submerged and then wait 60 s. Record the Initial Temperature of the water (Ti,w) on Data Table 16-1.
  8. Remove the probe and bring your cup over to the beaker with the boiling water. Be very careful not to spill any water out of the cup.
  9. Put on the goggles provided for you next to the boiling water. (This is Not Optional!!!)
  10. Gently remove 3 of the Brass Masses from the boiling water beaker by lifting them out with one of the metal hooks. Immediately, but gentlyplace the masses into the tap water in your Styrofoam cup and keep them there until step 14.
  11. Return your goggles and then carefully bring your Styrofoam cup back to your lab station. Immediately place the temperature probe back into the cup.
  12. Record the Temperature of the tap water every 15 s for 5 minutes. Record your measurements in Data Table 16-2.
  13. Circle the highest Temperature reached in Data Table 16-2 and record that value in Data Table 16-1. We will assume this temperature to be the Final Temperature of the tap water (Tf,w).
  14. Use the metal hook to remove the cubes and dry the cubesthe Best You Can!
  15. Mass the Brass cubes and record that total value in Data Table 16-1.
  16. What happened to Temperature of the Tap Water? What do you think happened to the Temperature of the Brass? When do you think both temperatures will stop changing?
  17. After considering the questions in step 16 talk with your lab partners about what you think the Final Temperature of the Brass Masses had at the moment the water reached its highest temperature? Record this Temperature as (Tf,metal) in Data Table 16-1.
  18. Dispose of the tap water in the sink and clean up your lab station. DO NOT place the masses back into the boiling water. You teacher will do this for you.
  19. In what direction do you think heat was flowing in the experiment? Circle your answer in Data Table 16-1.
  20. How does the amount of heat lost by the Brass compare to the amount of heat gained by the water? Circle your answer in Data Table 16-1. (Discuss your answers to steps 16, 17, 19, and 20 to your teacher before you move on to the calculation section of this experiment.)

Calculations and Analysis of Data

  1. Calculate the Change in Temperature that occurred in the Brass Mass. Record this calculation in Data Table 16-3.
  1. Calculate the Change in Temperature that occurred in the tap water. Record this calculation in Data Table 16-3.
  1. Using the “Heat Equation” calculate the amount of Heat gained by the water after the Brass Mass was dropped into it. (The Specific Heat Capacity of Water (cw) is 4.186 J/g0C)
  1. Devise a method to figure out what the Specific Heat Capacity of Brass is. Explain your method and then calculate (cbrass). Record your calculation in Data Table 16-3. This is your experimental value for cbrass.
  1. Using the Actual Value for cbrass given to you in Data Table 16-3. Calculate the % error of your Specific Heat Capacity of Brass value.
  1. Record your % error in Data Table 16-3.

% error is given by:

% error = (|cbrass actual - cbrass experimental|/cbrassactual)(100%)

Questions

  1. Why did we use a Styrofoam cup in this experiment?
  1. List as many factors as you can which might explain why your experimental value was not exactly equal to the accepted value.
  1. How could we change this lab to lower the percent error next time?
  1. What caused the Temperature pattern you recorded during the 5 minute period after the Brass was dropped into the water?
  1. How do you think “Heat” moves from one substance to another?
  1. What direction does Heat always flow?
  1. What is happening when you feel “Cold?”
  1. Why shouldn’t you leave a refrigerator door open for too long?
  1. The Specific Heat Capacity of water is very high. List some reasons why this might be useful or important to us on this planet.