Handling Chemicals Safely

Transcription

1 Handling Chemicals Safely 1. The chemical name, the concentration, and the hazard warnings. Remember, chemicals can have similar names, such as sulfide and sulfite. Also, if the experiment calls for 1 molar concentration, do not pick 0.1 molar or 10 molar concentrations. The hazard warnings include special precautions to take in handling a specific chemical. 2. At least twice. Be absolutely sure you have the right chemical in the correct concentration. 3. Yes. A chemical laboratory is not like a kitchen. Using approximate measures or adding ingredients in the wrong order can be dangerous. Be sure to weigh or measure each chemical accurately and precisely. Then add it to the experimental reaction exactly as you were instructed. 4. Throw leftover chemicals away in the proper waste container. Never return them to the original container, as other chemicals or dirt from the laboratory may have made your portion impure. If you return it to the original container, you risk contaminating the entire container. Products of experiments should also be thrown away in the proper waste container. Your teacher will tell you which chemicals go into which containers. 5. Always use a pipetter or pipetting bulb to draw up the amount you need. Practice with water before you try to measure a chemical. Never mouth-pipette. 6. Reading instructions all the way through will help you prepare for all safety needs and budget your time. You will clearly understand what you are supposed to be doing, and you will recognize if something is going wrong. 7. The smallest container that will do the job. If possible, use an unbreakable container. For example, carry powders In a plastic cup rather than a glass beaker. 8. Notify your teacher immediately. 9. Always pour acid into water. Remember AA add acid.

2 Glass Thbing Safety 1. Cuts from broken glass tubing, which often occur when students try to force the tubing through a hole in a rubber stopper. 2. Dip the Teflon tip in a lubricant (e.g., glycerin). Then push it through the stopper, remove the tip, and slide the tubing through the hollow inserter shaft. Remove the inserter from the stopper, leaving the tubing in the stopper. Wash the lubricant off the tubing and stopper before using them. Replace the Teflon tip in the inserter. 3. Lubricate the tubing before inserting it through the stopper. Protect your hands with leather gloves. 4. Put glycerin on the thermometer, use an inserter or leather gloves, and gently slide the thermometer into the stopper. Centrifuge Safety 1. Balance the centrifuge. Before you place your sample in the centrifuge, fill another test tube with an equal amount of water. Place the test tubes in opposite positions in the centrifuge to balance each other. 2. Turn it off. It is unbalanced. 3. Turn it off and allow it to come to a stop on its own. Never try to stop a centrifuge with your hands.

3 Bunsen Burner and Glassware Safety i. check to make sure there are no cracks in the hose. 2. Turn the gas on slowly. 3. Stand an arm s length away from the burner. 4. TURNOFFTHEGAS! 5. TURN OFF THE GAS! Also check other gas lines to make sure they are off. 6. No. Heat only open containers. Pressure building up in a closed container can cause it to burst. 7. No. Do not work near heated objects. Move your notebook away from heated objects before you write in it. Move your beaker away from heated objects before you add anything to it. 8. No. The glass might break. Heat stresses the glass, which is already weak at the cracked or starred point and increases its chance of breaking. 9. If you must carry a heated object, protect your hands with hot mitts, or use beaker tongs. 10. No. Flammable chemicals should be heated with a heating mantle or steam bath in a fume hood. They catch fire easily and should never be kept near a working Bunsen burner, let alone heated with one. Thermometer Safety 1. Both, although mercury is more toxic. 2. Tell your teacher. Your teacher should have a mercury cleanup kit, which must be used according to the instructions. The mercury is disposed of with the cleanup kit. Broken glass should be placed in the proper container. 3. You should know the thermometer s range, which is printed on it, and the approximate temperature you will be measuring (for example, water boils at 100 C). Be sure the ther mometer is designed for the temperature range you will be measuring. If not, obtain one for the proper range.

4 Dressing for Safety 1. Hard shoes with tops and closed toes. 2. Clothing should be sturdy and made of natural fabrics. It should not be extremely loose. Wear long pants or a long skirt to cover legs. Also wear older clothing and cover it with lab apron. It would be a shame to ruin new clothes in an accident. 3. Protect your eyes with safety goggles. 4. Rings and watches can trap corrosive chemicals against your skin, chemicals can also damage your jewelry. Contact lenses can trap chemical vapors against your eyes. If this happens, your eyelids might go into spasms that make it impossible to remove the lenses and wash out the chemical. 5. Cover your hands with gloves. Your teacher will provide gloves that are appropriate for the chemical you are using. Behavior in the Laboratory 1. No. The laboratory contains many chemicals that can damage your body. You and your classmates will be working with these chemicals as you study chemistry in the laboratory. It is inevitable that chemicals will spill, or be blown around. These chemicals could be spilled or blown onto your food or makeup. If you then eat chemically contaminated food, you will be eating the chemicals. If you apply chemical-splashed makeup, you will be applying dangerous chemicals to your skin. 2. Lower the burette to eye level; if you can t do that, stand on a step stool. 3. In a cabinet or cubbyhole, out of the aisle and off the countertop.

5 Emergency Equipment 1. Safety shower, eyewash fountain, fire extinguisher, fire blanket, and first aid kit. If you don t know where these are and how to use them, ask your teacher. 2. Cover a small fire in a container to extinguish it. Notify your teacher immediately if you have a larger fire. 3. Put out clothing fires in a safety shower. If the shower is not close by, stop, drop, and roll, then use a fire blanket carefully to extinguish any remaining flames. 24