A Complete CBL Experiment:
Heat of Solution

This experiment to determine the molar heat of solution is designed to illustrate the potential uses of the Texas Instruments Calculator-Based Lab(CBL) unit in conjunction with Vernier' Software's CHEMBIO program and Apple Computer's GraphLink computer interface. The temperature change that occurs when 0.01 mole of each compound is dissolved in 10.0 mL of distilled water is collected and stored by the calculator and CBL unit. The CHEMBIO program allows the student to specify the time interval between each reading and the number of samples to be recorded. The data is downloaded to Vernier's Graphical Analysis program using the GraphLink cable for further study.

To Install TI-Graph Link

1. Insert the "Graphical Analysis & TI-Graph Link" disk into your computer. Copy the enclosed "cbl" folder to your hard drive by dragging the folder onto the hard drive icon. Remove and return the disk.
   
2. Open the cbl folder . Drag the TI-82 font (which looks like a suitcase with a TI82 under it and A on top of it) from the cbl folder to the hard drive's system folder It will prompt you about installation. Click to accept installation.
   
3. Double-click on the TI-Graph Link-82 icon to test it. When open, it appears on the screen as a TI-82 calculator key-pad with a window. Use the File menu to close it.
   

To Load Programs from Computer to Calculator

1. Attach the TI-Graph Link cable to the modem port (the phone icon on the back of the computer) and to your TI-82.
   
2. Set your calculator to the Receive mode by the following sequence:
   • Press [2nd] [LINK] on the calculator.
     
   • Arrow over to Receive and press [ENTER].
     
   • The calculator will show you a message that it is Waiting.
     
3. Open TI-Graph Link-82. A blank (Information) window will appear.
   
4. Choose Group from the Send menu. A disk window appears and you need to find the cbl folder.
   
5. Open the Vernier folder with the TI-82 programs in it. Double click on the TI-82 Chem-Bio 82.g folder.
   
6. Click on SEND.
   
7. Follow the same set of instructions to load the any programs.
   
8. Once you've sent all programs, click on QUIT under the File menu.
   

If Individual files are needed:

1. Choose Program under the Send menu.
   
2. Find the folder with the individual files. Click on the folder and a list of individual programs should be listed.
   
3. Click on the program which you want to send and it will be highlighted. Click on the ADD button and that program will be added to a list at the bottom of the window. Several programs can be added to the list by repeating this procedure. When finished, click on the DONE button.
   
4. A screen which allows you to send button appears. The calculator must be in the (waiting) mode to send programs or you will get an error message.
   
5. If the program is already in your calculator or an earlier version is in your calculator, a message on the calculator will ask you if you want to rewrite, rename, or omit sending it.
   
6. The information window keeps a temporary list of the programs that have been sent.
   
7. Once you've sent all programs, click on QUIT under the File menu.
   

The Receive menu allows you to send programs and lists of data to the computer. Lists are written across the page as a series of numbers and not in columns. The list will be given the name corresponding to its number like "L1". It is desirable to change that name in order to recognize it later. This data cannot be imported to other applications except in the row type of format.

A list can be saved on the computer using the Receive menu and sent back to the calculator using the Send menu. The calculator allows you to Rename the list and will enter the data into a new list by giving it a name like "L2". This will prevent you from writing over the data in the list with the same current name.

To Print the TI-82 Screen

1. Attach the Graph-Link cable to the modem port and to the calculator.
   
2. Double click on the Link-82 icon (click on the monitor part of the icon).
   
3. Under the Receive menu, select Get LCD from TI-82.
   
4. Select 4x (or other desired size) for the size of your graph and be sure the printer is on.
   
5. Click on Print and click again on Print in the printer window.
   

Importing Data from the TI-82

A list of data can be imported form the lists on the calculator into a data table in Graphical Analysis. Connect the calculator to the computer using the TI-GRAPH LINK cable between the calculator and the modem port on the computer.

Computer:

1. Open Graphical Analysis and open a new file.
   
2. Under the File menu, click on IMPORT FROM TI-82/85.
   

1. Press [2nd] [LINK]. This will take you to the Send and Receive menu.
   
2. Under the Send menu, use the down arrow key to over down to (select all-) and press [ENTER].
   
3. Move down to the list(s) you need to send and press [ENTER] select. This places a small box in front of the list(s) selected. You can only select 2 lists. (Check with your teacher if you don't know where your data is stored.
   
4. Use the right arrow key to move over to (TRANSMIT).
   
5. Press [ENTER] on the calculator and the data will appear in the data table on the computer.
   
6. To add a second set of data to the same graph, select New Data Set from the DATA Window, then repeat the previous steps.
   

• The computer labels the column with the list number you transmitted (i.e., L1). This, along with the labels, units, titles, legends, connecting and regression lines and statistics, can be accessed and/or changed on the Graphical Analysis screen.
  
• You can transmit data into a column which already has data IF you click on an empty data cell after the last data entry. If you try this on a data cell which is already occupied, it will block the transmission and you will have to re transmit by starting the linking procedure all over again. You may have to press the command key to stop the attempt at transmission.
  
• If you can transmit data into a column that already has data, the computer will relabel the column with the list number you just transmitted.
  
• When you can transmit data into two columns, those columns will be displayed on the adjacent graph.
  
• A print screen option allows you to print the graph, the data (with length of data list limitations) and a text window for labeling.
  

CBL/TI-82 Experiment: Heat of Solution

This next section uses the CBL system connected to the TI-82 calculator. It is to familiarize you with the standard method of collecting data through a probe to upload to the computer into graphical analysis. All probes use the same basic menus accessed in this experiment.

• Measure out 0.010 mole samples of the chemicals assigned by your teacher. Fill a separate test tube with 10.0 mL of distilled water for each of the samples to by tested.
  
• Obtain and sign out a CBL SYSTEM(consists of a CBL, calculator, linking cable, and temperature probe)
  
• attach the calculator to the CBL unit
  
• firmly connect the link cord connectors to both the CBL and the calculator
  
• insert the TI temperature probe into channel 1.
  
• turn CBL system by pressing [ON]

TI-82

• turn TI-82 calculator by pressing [ON]
  
• push [prgm]
  
• Select CHEMBIO by pushing [1] or push [ENTER]
  
• press [ENTER] twice
  
• enter [1] (to set up probes)
  
• enter [1] (to set the number of probes) and press [ENTER]
  
• enter [1] (to choose temp probe)
  
• enter [1] (to choose the channel no.) and press [ENTER]
  
• enter [2] (to collect data)
  
• enter [2] (for time graph)
  
• enter 2 (for time between samples) and press [ENTER]
  
• enter 99 ( to set the number of samples) and press [ENTER]
  
• press [ENTER] (experiment length of 198.00 seconds appears)
  
• enter [1] (to use the time set up)
  
• enter 0 for the Ymin, press [ENTER]
  
• enter 35 for the Ymax, press [ENTER]
  
• enter 5 for the yscal, press [ENTER]
  
• place the temperature probe in one of the test tubes, then press [ENTER] to begin collecting data
  
• quickly add one of the 0.010 mole samples and stir the mixture with a stir rod.
  
• observe the dots that appear on the screen as the temperature changes
  
• press [ENTER] when the graph screen disappears
  
• push the right arrow key and observe displayed data points that are replotted on a new graph that fits the data collected
  
• push [ENTER] to continue
  
• enter [1] (no repeat)
  
• enter[5] (to quit)
  

Upload these lists to the computer with GraphLink

• Plug the calculator into the computer using the GraphLink cable.
  
• Open a new file for Vernier's Graphical Analysis program from the hard drive.
  
• Under the File pull down menu, select the option to "Import from TI-82/85".
  
• Follow the directions on the screen to link to the calculator.
  
• Press the [2nd] [LINK] keys on the calculator to begin.
  
• Press [2] to (Select All-). The data from the graph is saved as lists called L1 and L2, (This is all the way at the bottom of the program listings), so scroll down to them with the down arrow.
  
• Press [ENTER] to select L1, press the down arrow and [ENTER] to select L2.
  
• Use the right arrow button to select TRANSMIT, and press [ENTER]. The data should appear in the Graphical Analysis file. Now you can label the axis, supply units, add a connecting line, retitle the data set and the graph., analyze the graph, and print out the results.
  
• Save your data by using the File pull down menu to "Save As", then type your name followed by the letters "HeatSoln".
  
• From your graph, determine the maximum change in temperature. Calculate the molar heat of solution, assuming that the heat lost or gained during the dissolving process is equal to the heat energy change of the water.
  Heat change of water = (mass water)(temp. change)(0.004184 kJ/g*C)
  molar heat solution = (heat change of water)/moles of solute used
  
• Repeat the experiment, as directed by your teacher, using a different solid and another test tube with 10.0 mL of distilled water. The new data collected can be saved as a new data set on your original Graphical Analysis file or as a separate graph file.

Typical solids selected for this lab include ammonium nitrate, ammonium chloride, anhydrous calcium chloride and sodium hydroxide.(Check the Texas Instruments CBL Manual for a complete listing of chemicals that are safe to use with their temperature probe.) The endothermic nature of the dissolving of ammonium salts will cause the temperature of the water to drop 5-10ºC. The exothermic nature of dissolving calcium chloride or sodium hydroxide will cause a similar increase in temperature. Using 0.010 mole of solute per 10.0 mL of water produces solution that have concentrations which are approximately 1.0 molar. The required masses and accepted heat of solution values are: 0.80g ammonium nitrate +25.7 kJ/mole; 0.54g ammonium chloride +14.8 kJ/mole; 1.11g anhydrous calcium chloride -26.2 kJ/mole; 0.40g sodium hydroxide -44.5 kJ/mole.

Disposal: The solutions in the test tubes may be poured down the drain.

Suppliers:
School Mart, P.O. Box 80, Gambrills, MD 21054. ph. 800-285-2662

Texas Instruments Incorporated, ph. 800-TI-CARES

Vernier Software, 8565 S.W. Beaverton-Hillside Hwy., Portland, OR 97225-2429. ph. 503-297-5317

Presenter(s) for this month's seminar:

Mark Case and John Hnatow

Emmaus HS, 851 North St., Emmaus, PA 18049

A complete manual providing more detailed instructions and additional examples for using the CBL system in your science and math classes is available from the author's of this seminar. Write to Mark Case at the address above or e-mail to casemar@fast.net for more details.