LABORATORY HINTS AND TIPS: LABORATORY HINTS AND TIPS Presented by Mary K. Moore, Eastman Chemical Company


How Cold do you want to go?: How Cold do you want to go? When low temperatures are required for collecting gas samples, doing a reaction, or collecting volatile gas from a distillation, Try the following salt-ice mixtures 30g KCl in 100g ice water will cool to -10oC 33g NaCl in 100g ice water will cool to -21oC 85g MgCl2 in 100g ice water will cool to -34oC 143g CaCl2.6H2O in 100g ice water will cool to -55oC


Salt and Ice water not cold enough?: Salt and Ice water not cold enough? Dry ice proved an easy way to reach very low temperatures. Use crushed dry ice and mix with ethanol, acetone, isopropyl alcohol, or xylene. When using ethanol or acetone you can reach temperatures as low as -72oC.


Trouble placing rubber tubing on glassware or metal?: Trouble placing rubber tubing on glassware or metal? Add a small amount of acetone in the end of your rubber tubing before placing it on the glassware or metal. This helps fuse the tubing to the object. Use water and Kevlar gloves for inserting glass tubing and thermometers into rubber stoppers.


Have you "burped" liquid when using a funnel to add liquids to a sample jar? : Have you "burped" liquid when using a funnel to add liquids to a sample jar? Unfold a paper clip and place it between the funnel and the container. This will allow air to escape.


Pouring Liquids from Beakers : Pouring Liquids from Beakers Hold a glass stirring rod against the pouring lip of the beaker Tilt the container, allowing liquid to flow around the stirring rod, the liquid will be guided into the beaker.


Have you ever had to clean up a mercury spill?: Have you ever had to clean up a mercury spill? When using mercury filled monometers in the fume hoods, place a polyethylene tub under the monometer to collect the mercury if the monometer breaks.


Weighing out liquids : Weighing out liquids Pour approximate liquid amount into an Erlenmeyer flask or a beaker. Use a disposable pipette for final measuring.


Have you ever had trouble with excel spreadsheets? Try color coding.: Have you ever had trouble with excel spreadsheets? Try color coding.


Do you add to much grease on stopcocks?: Do you add to much grease on stopcocks? Put grease in a 50ml plastic syringe. This way you can add a small amount of grease on the connection. After using, relieve pressure by pulling back on the plunger. Store for further use. Use a paper towel and get a small amount of grease on the towel and rub on the glass-ground connection.


Some Ideas for balances.: Some Ideas for balances. Keep the space beside the balance clear, allowing you to weigh your objects and place them to the side. Keep a pad of paper and a pen next to your balances to write weights down.


Weighing Solids: Weighing Solids When weighing dry samples, place a bi-fold towel under the container. If the sample spills, the towel will catch the solids. After weighing, pick-up the towel from each side and bring them together, forming a "V". You now have a built-in funnel.


Problems with Crystallization?: Problems with Crystallization? One of the following techniques or some combination of them may be helpful Scratch the side of the beaker with a glass stirring rod. Use a freshly cut piece with an up and down motion. "Seed" with the original material, by dropping some into the cooled flask. Cool the solution in a freezer or freezing mixture. Add crumbs of dry ice. Let stand for a long period of time. Change solvent system


Cutting small diameter glass tubing: Cutting small diameter glass tubing Always use cut resistant gloves! Scratch the glass rod with a three-cornered file or glass cutter, use considerable pressure, however, do not saw. Add a drop of water to the filed section of the glass rod. Using little force, pull back on the glass rod and push thumbs outward quickly to break the glass.


Waste Disposal : Waste Disposal Segregate wastes in clearly marked containers to avoid possible chemical reactions. Consider the possibility of spontaneous reactions, explosions, and fire. Minimize waste


Volumetric Flask : Volumetric Flask Use a thin gauge wire to attach the stopper to your volumetric flask. This will prevent you from losing the stopper.


CONTRIBUTORS: CONTRIBUTORS John Engelman, SC Johnson Daphne Eggers, Eastman Chemical Company Juanelle Lambert, Eastman Chemical Company Janet Smith, Dow Corning Corporation Doug Chaffin, Eastman Chemical Company Andrew Vetter, Eastman Chemical Company John Moncier, Eastman Chemical Company Amy Nave, Eastman Chemical Company Vicki Bledsoe, Eastman Chemical Company