Introduction
Chemistry is a hands-on science class. This means that while you will be learning the background, theory, and calculation methods in a standard lecture setting, you will also be learning techniques and skills in the lab. In the lab, you will be using chemicals and specialized tools and equipment to put into practice the principles you learn in lecture.
The main emphasis in the lab – even above and beyond the skills, techniques, and theory – is going to be on working in the lab safely. If you burn your hand during a lab activity, you will probably miss the point of that lab and might be shy about going back into the lab area; this is not a Good Thing.
Objectives
After doing this lab, students will be able to:
§ state some of the basic principles of lab safety
§ apply knowledge of basic principles of lab safety to identify unsafe laboratory conditions
§ work in the lab safely
Materials and Equipment
See “Introduction to Basic Lab Equipment” for illustrations and examples of lab equipment and tools
Safety Considerations
This entire section is about safety considerations!
Part A: General Guidelines
1. When first entering a science room, do not touch any equipment, chemicals, or other materials in the lab area until you are instructed to do so.
2. Be prepared for your work in the lab. Read and, if necessary, re-read all procedures thoroughly before entering the lab area (your lab instructor will be able to tell if you have read the procedure or not). Read chemical labels and equipment instructions carefully before use. Set up and use the prescribed apparatus as directed in the procedure or by your instructor.
3. Do not eat food or candy, drink beverages, or chew gum in the lab. Do not use lab glassware as containers for food or beverages.
4. Never work alone. No student may work in the lab without an instructor present.
5. Conduct yourself in a responsible manner any time you are in the lab area. Under no circumstances, and at no time, will horseplay, practical jokes, or pranks be tolerated. Playing around in the lab is grounds for immediate dismissal from the lab, a grade of zero for that lab, and possible suspension from future labs.
6. Any time chemicals, heat, or glassware are used, students will wear safety glasses/goggles. There will be no exceptions to this rule!
7. Follow all written and verbal instructions carefully. If you do not understand a direction or part of a proce-dure, ask the instructor before going any farther in the experiment.
8. Perform only those experiments authorized by the instructor. Never do anything in the lab that is not called for in the procedure or by your instructor.
9. Experiments must be personally monitored at all times. You will be assigned a lab space in which to work; stay there while you’re doing your experiment. Do not wander around the room, distract other students, or interfere with the experiments of others. (See Rule A – 5 for further information.)
10. Observe good housekeeping practices in the lab. Work areas should be kept clean at all times. Bring only your lab instructions and data sheets to the lab. Other materials (books, purses, calculators, book bags, etc.) should be left in the classroom area.
11. Keep the aisles clear. This facilitates movement in the lab area and reduces the chances that someone will trip over something.
12. Be alert and proceed with caution at all times in the lab. Notify the instructor immediately of any unsafe con-ditions you observe.
13. Students are not allowed in the storage rooms or chemical preparation area unless given specific permission by the instructor.
14. Know what to do if there is a fire drill during a lab period.
a. Close all chemical containers.
b. Turn off all gas valves and burners.
c. Make sure the fume hood is turned off.
d. Make sure any electrical equipment is turned off.
15. Know the locations and operating procedures of all safety equipment: first aid kit, eyewash station, safety shower, fire extinguisher, and fire blanket. Know where the fire alarm and the exits are located.
16. Always work in a well-ventilated area. Use the fume hood when working with volatile substances or poison-ous vapors. Never place your head in the fume hood.
17. When working with knives, scissors, scalpels, or other sharp instruments, always carry them with tips and points pointing down and away from you. Cut away from your body. Never try to catch falling sharp instru-ments. Grasp sharp instruments only by the handles.
Part B: Clothing, Hair, and Jewelry
1. We said it before, and we’ll say it again. Any time chemicals, heat, or glassware are used, students will wear safety glasses/goggles. There will be no exceptions to this rule!
2. Contact lenses should not be worn in the lab unless you have permission from your instructor. Chemicals could splash up under the lenses and permanently damage your corneas. Noxious gases can permeate soft lenses.
3. Long hair is a fire hazard in the lab; it must be tied back.
4. Rings and dangling bracelets should be removed before starting the lab activity. Some of the chemicals we will use will corrode jewelry; sterling silver is particularly vulnerable. Rings can trap corrosive or irritating chemicals next to the skin and make them difficult (if not impossible) to wash away completely.
5. Loose or baggy clothing must be secured before starting the lab activity. Billowy sleeves can knock over tall glassware or get caught in a Bunsen burner. You can trip over pants legs that are too long and/or baggy.
6. Do not lean down over the lab bench and support yourself on your forearms; acid or base residue on the bench can eat through your sleeves and find its way to your skin.
7. If aprons are provided, wear them.
Part C: Handling Chemicals
1. All chemicals in the laboratory are to be considered dangerous. Do not touch or smell any chemicals unless instructed to do so (the proper technique for smelling chemical fumes will be demonstrated to you). Never taste any chemical in the lab!
2. Check the labels on chemical bottles twice before you remove any of the contents. Take only as much chemical as you need.
3. Never return unused chemicals to their original containers.
4. When transferring chemicals from one container to another, hold the containers away from your body.
5. Never use mouth suction to fill a pipet. Use a rubber bulb or pipet pump.
6. Keep your hands away from your face, eyes, mouth, and body while using chemicals or preserved specimens. Wash your hands thoroughly with soap and water after performing all experiments. Clean, rinse, and wipe dry all work surfaces and apparatus at the end of the experiment. Return all equipment clean and in working order to the proper storage area.
7. Acids must be handled with extreme caution. You will be shown the proper method for diluting strong acids. Always add acid to water, swirl or stir the solution, and be careful of the heat produced, especially with sulfuric, nitric, or phosphoric acids.
8. Likewise, handle bases with extreme caution. Bases can cause instantaneous, permanent eye damage. Be careful of the heat produced when dissolving solid sodium or potassium hydroxide; use an ice bath if neces-sary.
9. Handle flammable hazardous liquids (ethanol, methanol, acetone, etc.) carefully. Never dispense flammable liquids anywhere near an open flame or source of heat.
10. Take great care when transferring acids and other chemicals from one part of the lab to another (e.g., from the fume hood to your lab station). Hold them securely and walk carefully.
11. Dispose of all chemical waste properly. Never mix chemicals in sink drains; sinks are to be used only for water and those solutions designated by the instructor. Solid chemicals, metals, matches, filter paper, and other insoluble materials are to be disposed of in the proper waste containers, not in the sink. Check the labels of all waste containers twice before adding your chemical waste to the container.
12. Never remove chemicals or other materials from the lab area.
Part D: Handling Glassware and Equipment
1. Examine glassware before you use it. Do not use chipped, cracked, nicked, or dirty glassware.
2. Carry glass tubing, especially long pieces, in a vertical (up-and-down) position to minimize the chances of injury.
3. Do not immerse hot glassware in cold water – it may shatter. Likewise, do not pour cold solutions into hot glassware.
4. Inserting and removing glass tubing from rubber stoppers can be dangerous. Use an insertion tool if one is available. Always lubricate glassware (tubing, thermometers, etc.) with glycerin before you attempt to insert it in a stopper. Protect your hands with leather gloves or multiple thicknesses of paper toweling when working with tubing and stoppers. If a piece of glassware gets stuck in a stopper, take it to your instructor; don’t try to remove it yourself.
5. Never handle broken glass with your bare hands. Use a brush and dustpan to clean up broken glass. Place broken or waste glassware in the designated disposal container.
6. Report damaged electrical equipment immediately. Look for things such as frayed cords, exposed wires, and loose connections. Do not use damaged electrical equipment!
7. When removing an electrical plug from the power outlet, grasp the plug, not the cord. Make sure your hands are completely dry before touching an electrical switch, plug, or outlet.
8. Fill wash bottles only with distilled water and use them only as intended – rinsing glassware and equipment, adding water to a container, etc. (See Rule A – 5 for further information.)
9. If you do not understand how to use a piece of equipment, ask your instructor for help!
Part E: Heating Materials
1. Use extreme caution when using a gas burner (Bunsen burner, Tirrill burner, or Meker burner). Take care that hair, clothing, and hands are a safe distance from the flame at all times – and never reach over/across an exposed flame.
2. Light gas or alcohol burners only as demonstrated by your instructor.
3. Do not put any substance in a burner flame unless specifically instructed to do so.
4. Never leave a lit burner unattended. Never leave anything that is being heated or is visibly reacting unattended.
5. Never touch a burner or hot plate – or anything that has been heated – without first checking to see if it is hot. Determine if it is hot by bringing the back of your hand close to it before you actually touch it.
6. Never look into a container that is being heated!
7. You will be instructed in the proper method of heating and boiling liquids in test tubes. Do not point the open end of a test tube being heated at yourself or anyone else.
8. Never heat materials in a closed container!
9. Do not place hot apparatus directly on the lab bench. Always use an insulating pad. Allow plenty of time for hot apparatus to cool before touching it.
10. Heated metals and glass remain hot for a long time, and you can not tell just by looking whether they are hot or cold. When in doubt, use tongs or heat-protective gloves to handle objects.
11. Always turn the burner or hot plate off when it is not in use! Make sure that the burner or hot plate is turned off before you leave the lab area.
Part F: Handling Accidents or Injuries
1. If an accident (spill, breakage, etc.) or injury (cut, burn, etc.) occurs in the lab, do not panic.
2. Report any accident or injury – no matter how trivial it may appear – to your instructor immediately.
3. If you or your lab partner(s) are hurt, immediately yell out “Code One! Code One!” to get your instructor’s immediate and undivided attention. (See Rule A – 5 for further information.)
4. If a chemical should splash in your eye(s) or on your skin, notify your instructor immediately.
a. If the splash is in your eye(s), make your way to the eyewash station (get help if necessary) and notify your instructor on your way there.
b. If the splash is on your skin, make your way to the sink and notify your instructor on your way there.
c. If the splash is on your body, make your way to the safety shower and notify your instructor on your way there.
5. If a mercury thermometer breaks, do not touch the mercury. Notify your instructor immediately.
If it seems as if there are quite a few rules to remember, you’re right – there are a lot of safety rules to remember. Then again, there are a lot of potential hazards in a chemistry lab. Between the chemicals and fumes, the burners and hot materials, and glassware, there are a lot of things to keep up with. It’s just something you have to do, plain and simple.
That having been said, you shouldn’t be paranoid about working in the lab, either. Your instructor has done each of the lab activities before, and knows about any special hazards or concerns associated with them. He or she will take time before the lab to alert you to these hazards or concerns – and may give you some tips to make the lab go more smoothly. Listen to your instructor!