DRAFT: This module has unpublished changes.

Materials and Equipment:

  

- Data collection system                         - Beaker, 1500-mL

- Absolute pressure sensor with              -Balance (1 per class)

   quick-release connectors and              - Rubber stopper with one hole

  plastic tubing                                       - 3 M Hydrogen chloride (HCl), 100 mL

- Sensor extension cable                       - Unkown metal (3 pieces), 0.2 g

- Stainless steel temperature sensor       -Electrical tape, roll

- Graduated cylinder, 10-mL or 25-mL                          

- Graduated cylinder, 250-mL

- Erlenmyer flask, 250-mL            

 

 Methods:

  

1. Start a new experiment on the data collection system.

 

2. Connect a stainless steel temperature sensor and a pressure sensor to the data collection system.

  

3. Place the barbed connector tightly into the rubber stopper. Connect the barbed connector to the pressure port of the sensor with a piece of tubing. 

 

4. Wrap the Erlenmyer flask with 10 to 15 rounds of electric tape. This is a preventative measure in case the flask cracks. The tape keeps the glass pieces together. 

 

5. Mount the 250-mL Erlenmyer flask in a water bath in a 1500-mL beaker. The water should cover as much of the flask as possible. 

 

6. Place the temperature sensor in the water bath. 

 

7. Measure between 0.150 g and 0.180 g of the unknown metal to the nearest milligram. Record the mass of the sample in table 3. 

 

8. Using a graduated cylinder, measure 20.0 mL of 3.0 M HCl solution and transfer it into the 250-mL Erlenmyer flask. 

 

9. Start recording data. 

 

10. Record the initial pressure in Table 3. 

 

11. Drop the measured piece of unknown metal into the flask and immediately insert the rubber stopper airtight. (Make sure that the stopper is sitting firmly as pressure will build in the flask and a loose stopper may pop out. If this happens, you will need to repeat the experiment).

 

12. Continue to monitor the pressure. Once the hissing in the flask is over and the pressure has leveled off, record the final pressure and the temperature readings in Table 3. 

 

13. Stop data recording. You do not need to save your data.

 

14. Remove the stopper carefully and dispose of the spent acid solution properly.  

 

15. Repeat steps 7-14 for two more trials.

 

16. Fill the Erlenmyer flask to the top with water and, over a sink or waste container, insert the stopper. Using the 250-mL graduataed cylinder, measure the volume of the water to obtain the volume of the flask and record the value in Table 3.  

DRAFT: This module has unpublished changes.