LABORATORY EYE PROTECTION

Preview This section describes the eye protection needed when working in the laboratory, and how you can protect your eyes against chemicals in introductory labs. 

Young cat, if you keep your eyes open enough, oh, the stuff you would learn The most wonderful stuff  

A student was removing and disassembling a reflux condenser when the solution bumped and splashed the solution onto her face and chest. She was wearing chemical splash goggles but a poor seal of the goggles with her face still allowed some solution to enter her eyes. She was ushered to a safety shower and eventually examined at an emergency room. There was no permanent damage to her eyes. 

What lessons can be learned from these incidents  

The Eyes Have It And You Should Want to Keep Them 

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Eye protection was rarely practiced in older laboratories except when particularly hazardous work was carried out. Today such protection is mandatory for practically all laboratory operations. 

Cleanliness comes very close to godliness in the laboratory. A worker always washes hands before eating or smoking, and many times in between. One thoughtful laboratory operator placed bottles of liquid skin cleanser and hand lotion next to all sinks. Apart from personal cleanliness, there are other important forms of protection for the worker. Most notable among these is eye protection. 

Eye protection is mandatory for almost all types of laboratory work. A wide selection of safety glasses and goggles is available from suppliers of safety equipment, many especially designed for specific purposes. There are official specifications for such glasses, and it is unwise to buy any w hich are claimed to be as good as the ones guaranteed to meet those specifications. 

Eye protection — safety glasses or goggles - is mandatory whenever any pyrotechnic composition is being prepared or tested. Necessary equipment includes a mortar and pestle, a laboratory balance, a soft bristle brush, several 2-3 inch lengths of fireworks-type safety fuse (available from many hobby stores), and a fireproof stone or composite slab on which to conduct burning tests. 

All these reactions are best carried out (a) under an atmosphere of nitrogen and (b) with mechanical stirring. General safety precautions should be maintained, namely, the use of eye protection in the laboratory, proper gloves to avoid skin contact with chemicals, and provision of a hood or dry box with adequate ventilation for all chemical manipulations. 

Preparation of Chromium. Perform the experiment in the presence of your instructor, in a fume cupboard Wear eye protection or a mask ) Roast chromium(III) oxide in an iron crucible. Triturate potassium dichromate crystals in a mortar, melt the powder in a porcelain crucible with the flame of a gas burner, pour the substance onto a glazed tile plate, and after it solidifies again triturate it into a powder. Weigh 12 g of roasted chromium(III) oxide, 12 g of the fused potassium dichromate, and 10 g of an aluminium powder, and thoroughly mix all the substances in a mortar. Spill 10 g of a calcium fluoride powder onto the bottom of a chamotte crucible, and then the prepared mixture. (If there is no chamotte crucible in your laboratory, make a box from asbestos paper in the form of a crucible and fasten it with wire.) Tamp the substance with a pestle and make a hollow in the middle using a test tube (see Fig. 120). 

Wear neoprene gloves,17 laboratory coat, and eye protection. Cover spill with a 1 1 1 mixture by weight of sodium carbonate or calcium carbonate, clay cat litter (bentonite), and sand. Scoop into a beaker or pail. In the fume hood, slowly add the acid mixture to a pail of cold water. When reaction ceases, neutralize with more sodium carbonate if necessary. When solids have settled, decant liquid into drain with 50 times its volume of water. Discard solid residue with normal refuse. Ventilate site of spillage well to evaporate remaining liquid and dispel vapor.18,19... 

Small Quantities. Wear neoprene gloves, laboratory coat and eye protection. Work in the fume hood. Add slowly to large volume of cold water in a plastic pail. Neutralize with 5% sodium hydroxide solution or sodium carbonate and pour into the drain.18... 

Small Quantities. Wear nitrile rubber gloves, laboratory coat, and eye protection. Work in the fume hood. To decompose 5 mL (5.4 g) of acetic anhydride, place 60 mL of a 2.5 M sodium hydroxide solution (prepared by dissolving 6.0 g of NaOH in 60 mL of water) in a 250-mL, three-necked, round-bottom flask equipped with a stirrer, dropping funnel, and thermometer. Add the acetic anhydride to the dropping funnel and run it dropwise into stirred solution at such a rate that the temperature does not rise above 35°C. Allow to stir at room temperature overnight. Neutralize solution to pH 7 with 2 M hydrochloric acid (slowly add 16 mL of concentrated acid to 80 mL of cold water) and pour into the drain.23... 

Shut off all possible sources of ignition. Instruct others to keep a safe distance. Wear breathing apparatus, eye protection, laboratory coat, and nitrile rubber gloves. Cover the spill with a 1 1 1 mixture by weight of sodium carbonate or calcium carbonate, clay cat... 

Small Quantities. Work in the fume hood. Wear eye protection, nitrile rubber gloves and laboratory coat. Place 6.0 g (7 mL, 0.107 mol) of acrolein in a 1 L, three-necked, round-bottom flask equipped with a thermometer, stirrer, and dropping funnel. Over a period of 10 minutes, add 50 mL of a solution of 63 g (0.4 mol) of potassium permanganate in 700 mL of water. If the purple color is not discharged, warm the mixture on steam bath until it becomes brown. Add the remainder of the permanganate solution at such a rate that the temperature does not exceed 45°C. When addition is complete, heat the mixture on the steam bath to 70-80°C, while stirring, for 1 hour. Cool the mixture to room temperature, and acidify to pH 1 with 3 M sulfuric acid (16 mL of concentrated acid cautiously added to 84 mL of cold water). Add solid sodium bisulfite, while stirring, until a colorless solution is produced. Wash the solution into the drain with water.7... 

Small Quantities. Wear nitrile rubber gloves, laboratory coat, and eye protection. Work in the fume hood. Dissolve the acrylic acid in water to give a 10% solution. For each 5 mL of this solution, add 250 mL of 2% aqueous sodium hydroxide and, while stirring, 10 g of potassium permanganate. Stir at room temperature for 48 hours. Add solid sodium bisulfite until the solution is colorless, neutralize with 5% hydrochloric acid, and pour the liquid into the drain. Discard any small amount of brown solid (manganese dioxide) with regular refuse.7... 

Small Quantities. Wear nitrile rubber gloves, laboratory coat, and eye protection. In the fume hood, place the aluminum bromide in a large evaporating dish. Cover the aluminum bromide with excess solid sodium carbonate or calcium carbonate. Very slowly add the mixture to a pail of cold water. Allow to stand for 24 hours. Test pH of the solution and neutralize if necessary. Pour the solution into the drain, flushing with at least 50 times its volume of water. Treat the solid residue as normal refuse.5,6... 

Wear nitrile rubber gloves, laboratory coat, and eye protection, and work from behind body shield where possible. Keep available pulverized dolomite or dry graphite for firefighting. Eliminate all sources of ignition. Follow waste disposal procedure. 

Small Quantities. Wear nitrile rubber gloves, eye protection, all-purpose or special canister respirator for ammonia, and laboratory coat. Pour into a large container of water and neutralize with 5% hydrochloric acid. Pour into the drain.6... 

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