Safety Lab Goggles are required! Apron is optional!

Transcription

1 Goggles are required! Apron is optional! Station 1: What would acid do to your eye? Materials: 6M hydrochloric acid, dropper, two petri dishes, egg whites. Procedure: 1. Separate the egg white from the egg yoke. 2. Pour egg white into the glass dish. 3. Put four drops of 6M HCl on the egg white. 4. Observe the reaction and describe what happened. 5. Use the tweezers to remove any damaged egg material. 6. To cleanup egg whites that are too damaged to reuse, rinse down the drain with plenty of water. Use fingers and water to rub off any remaining egg material. 7. Rinse the glass plate.

2 Station 2: Where to I point this thing? Materials: Test tube, test tube clamps, test tube rack, fire starter, Bunsen burner, water, target paper. Procedure: 1. Obtain a test tube. Hold it with the test tube clamps. 2. Put one hand just under the test tube. Then pinch the test tube holder so it falls into your hand. Please be careful not to drop or break the test tube. THIS IS WRONG! 3. Now, reset the test tube holder. Grip is so that when you pinch, it does not drop with thumb and fingers on top and below the end circle. THIS is the CORRECT way to grip it. 4. Fill your test tube ¼ full with water. 5. Locate the colored paper on the counter top. 6. Set the colored paper down just next to the burner so that the test tube will point over the paper, but not towards any people. 7. Gently move your test tube around in the flame so the hottest part is heating the water in the test tube (the tip of the inner blue cone). Make sure the open mouth of the test tube is facing the paper. 8. As soon as any moisture hits the paper, remove the test tube and dump the water down the sink. 9. Gently unclamp the test tube and put it back in the rack. 10. LEAVE THE BUNSEN BURNER BURNING FOR NEXT GROUP.

3 Station 3: Making Solutions Safety Lab Materials: 50 ml graduated cylinder, table salt, balance, weighing paper, and a stirring rod. Procedure: To prepare a solution of a given percentage, dissolve the number of grams of solid solute equal to the percentage in enough water to make 40 ml of the solution. To prepare a 5% sodium chloride solution: 1. Place the weighing boat on the electronic balance and find its mass (or tare the scale). 2. Add 2 grams of sodium chloride to the boat. 3. Put the 2 grams of sodium chloride in a 100 ml graduated cylinder. 4. Add enough water to bring the volume of the solution to 40 ml. 5. Stir or swirl, and make observations. 6. Describe what happened to the salt crystals. Watch closely. 7. Save this saltwater solution for the next station. *When diluting an acid such as hydrochloric acid, always add the acid to the water! Pour acid down the stirring rod. Diluting an acid also produces heat.

4 Station 4: Hot plates, % yield & separating mixtures Materials: Salt water from pervious station, evaporating dish, hot plate, beaker tongs, rag, scale, and ring stand metal plates. Procedure: Separate parts of a mixture by evaporating the water away from the 5% sodium chloride solution leaving behind the salt: 1. Mass your evaporating dish and record in your data table. 2. Pour exactly 10 ml of your solution from station 3 into the evaporating dish. 3. Using the beaker tongs, place the evaporating dish with the saltwater on the hot plate 4. Boil away the water until only dry salt remains. 5. Set hot, dry evaporating dish on the metal plates until cool enough to touch by hand. 6. When cooled, mass the dish including the dried salt and record in your data table. 7. Clean your dishes and return supplies. Station 3 will need to get back the graduated cylinder. 8. Finish lab report calculations.

5 Station 5: Using Hot baths and hot glass wear. For safety reasons, use a hot plate instead of an open flame any time you heat a flammable or dangerous liquid. To use a hot plate, it must first be plugged into the electric line. Some hot plates have an on-off switch that must be turned on to use. Also, most hot plates have a variable heat adjustment knob to get just the right temperature. Materials: Hot plate, 400 ml beaker, test tubes, tap water, beaker tongs, test tube holders, thermometer, and a test tube rack. Procedure: 1. Keep the 400 ml half full of gently boiling water. 2. Keep them on the hot plate. 3. You and your partner, fill your own test tube ¼ full of water. 4. Take the temperature of the room temperature water. Record it in your data table. 5. Using test tube clamps put the test tube into the beaker of water. Be careful not to hit the glass on glass or it will break and possibly burn you with steam. 6. Start Timing 7. Take the temperature of the water in the test tube every 30 seconds for 2 ½ minutes. Don t let the bottom of the thermometer touch the bottom of the test tubes. 8. Leave the hot plates on when finished, using the tongs refill the water so it remains ½ full in the 400ml Beaker so the next group can use it. 9. Last group, using the appropriate tongs, empty all the containers, being careful not to splash hot water on anyone. Do not clink hot glassware together or rinse hot glassware with cold water. Turn off the hot plates, empty all waters, set thermometers on counter. Sample Data Table: DO NOT WRITE HERE! Time 0 sec. 30 sec. 1 min. 1 ½ min. 2 min. 2 ½ min. Temperature C

6 Station 6: Youtubing? Materials: Glass tubing, Bunsen burners, glass trash disposal container, matches, and metal plates. Procedure: 1. Get a piece of glass from the tub labelled cool class. 2. If your piece is bent, your job is to straighten the glass without causing the glass to look collapse or look melted. 3. If your glass is straight, your job is to bend the glass 90 without causing the glass to look collapse or look melted. 4. To heat the glass tubing put hold with both hands. Place the middle of the tubing just touching the top of the inner blue tip of the flame. Roll is back and forth with your thumbs and forefingers. 5. Slowly, you will feel that it can bend. Continue to roll it as you very slowly bend it to the angle you want. 6. Place your modified hot piece of glass on the metal plates so they can cool.

7 Station 7 Bunsen Burner Operation (Perform on day of test, so practice a lot) Materials: Bunsen burner, and matches. Procedure: 1. Connect the hose of the burner to the gas supply. 2. Make sure all three valves are turned off. A trick is righten tighten (clockwise). 1 st valve is main gas valve, 2 nd valve is bottom gas knob on Bunsen Burner, 3 rd valve is the air adjustment as part of the upper neck (needs to be visibly closed). 3. Light a match and hold just next to lip of Bunsen Burner mouth. 4. Open the main valve 1 st, then open the bottom valve of the Bunsen burner. The flame will gently light. 5. To maximize the amount of gas, turn the valve on the bottom of the burner only until it seems to be done growing. (do not keep turning or you can burn yourself) 6. Play with the air inlet valve on burner witch is at the bottom of the neck. As you let air in, the flame will change. 7. Adjust the air so that you create an inner blue cone with a lighter, outer blue cone. 8. Finally, you ll need to tighten the bottom valve of the Bunsen burner to make a tight, smaller, more intense blue cone. Sometimes, you ll need to play with both valves on the burner to fine tune. 9. Finish by closing the air valve, creating a sloppy yellow flame. 10. When done, turn off the main gas valve, close bottom gas valves, and disconnect all the hoses so the next group needs to redo everything.

8 Results and Conclusion: Name: Period: Station 1: Diagram the egg, dropper with acid, and the damage that occurs. Station 1 Conclusion: What part of your body would the egg best represent? Describe the speed and type of damage caused by the acid. Station 2: Draw a picture of the flame, water, test tube, angle, and what happens to the water in the test tube. Station 2 Conclusion: Where should you point the open end of a test tube when heating? Explain the wrong way to grip the test tube holders.

9 Station 3: Label the amounts of salt and water clearly, with units in a picture of your solution. Also label the % of the solution. Station 3 Conclusion: What is the only way to effectively clean salt from the counter? What is the only way to effectively clean saltwater from containers and surfaces? Station 4: As you follow directions, fill in the data table below, then show your work, with units for any calculations. Data Table: Mass of empty, dry evaporating dish. Mass of dried salt and evaporating dish. Station 4 Conclusion: In theory, what is the mass of salt that should be in your 10 ml of saltwater solution? How do you know this is the expected amount? Show your work for calculating the actual amount of salt recovered. In Chemistry, we use % yield to determine how well a lab produces what we hope to create. Show your work below for calculating your % yield of salt after boiling away the water. % yeild = Actual Salt in Lab Theoretical amount of salt you should have recovered =

10 Station 5: Diagram the heater, beaker, test tubes, thermometers, and test tube holders in use. Fill in the data table below. Time 0 sec. 30 sec. 1 min. 1 ½ min. 2 min. 2 ½ min. Temperature C Conclusion: What type of substance would be smart to heat in a water bath rather than an open flame? Explain why. Station 6: Diagram a quality picture of exactly what type of flame was used, and where the glass had to be in order to bend it. Include fingers in your picture to show where to hold it, and how to keep safe. Conclusion: Some students inevitably were burnt in this lab. Explain how this probably happened and how to avoid it. How can a person test something to see if it is hot before touching it?

11 Station 7 Practice Test: Diagram a Bunsen burner, hose, & valve with a focus on the three main adjustable parts in the system. Be sure to draw the perfect, tight, intense blue double cone. Test Sequence = 1. All three valves off & Checked, 2. light match 3. place burning match tip near burner top 4. open main gas valve on counter top then burner valve on bottom of burner, 5. open till fully open (don t go too far), 6. open neck valve for fresh air mix until it forms tight inner blue cone, 7. close bottom gas valve to tighten and focus inner blue cone, \ 8. completely close neck valve to create loose yellow flame, 9. shut down both gas valves, 10. dead matches in tin. Conclusion: Which two valves affect gas flow? Which valve affects air mixture allowed