Lesson 1: Safety in the Laboratory

Safety Concerns in the Laboratory:

It has been said that there are no nonhazardous chemicals, only nonhazardous ways of dealing with them. Water, for example, is not generally considered to be a hazardous chemical but many people die each year from drowning. Lead is considered to be a hazardous chemical, but I’m sure that its ingestion as a poison contributes to far fewer deaths and injuries than its use in bullets. There are a variety of ways in which you can be harmed by chemicals, and there are also a variety of ways that you can use to help protect yourself from being harmed by chemicals.

First of all, pay attention to what you are doing and what you are working with.

You should always wear safety glasses or goggles when working with dangerous chemicals. Remember, your eyes are irreplaceable. Since you won't always know which chemicals are dangerous, the safest thing is to wear the glasses whenever you are working with chemicals. Also wear them when you're near someone working with chemicals. We $ have some variety of different styles so find a style that fits best and use them.

You should know where the laboratory safety equipment is located. Take a moment when you are in the lab to have the instructor show you where the eyewashes are and how to use them. Also, find out about the other safety equipment in the lab like the emergency shower, the fire extinguisher, and the first aid kit. When working with chemicals, if you should get any in your eye, use the special eyewash.

$ Tell the instructor of any accidents immediately.

Keep food and drinks out of the laboratory work area. In our particular lab that corresponds to the tiled floor area.

When dealing with chemicals, you should always read labels carefully to be absolutely certain you have the right chemical. Sometimes names are very similar. If you don't get the right chemical, it may ruin your experiment; and of course, you might get a dangerous reaction.

Sometimes you will be told to use a certain concentration of a solution. In those cases, be sure you check the label for concentration as well as the name of the chemical. Sometimes the concentration will be indicated as "concentrated" or "diluted." Sometimes it will be given in terms of numbers--usually as a number followed by a capital M or N. For example you might be told to use "2M sodium chloride". Then you should check for the "2M" as well as the "sodium chloride" on the label. As far as what those numbers mean, don't worry about that right now; you'll deal with that next term. You should be aware though that the higher the number, the more concentrated the chemical is.

Also, never mix chemicals that you haven't been told to mix without an OK from the instructor.

If you spill a chemical, wipe it up immediately and advise the instructor.

Acids, in general, are fairly hazardous chemicals so you should be sure to wear safety glasses while using them. If you should get any one of them (or any other chemical) on you, rinse it off immediately with lots of water and let the instructor know what you spilled--on your way to rinsing it off. That is another very important reason for reading the labels. Know what chemicals you are dealing with because if there is an emergency, quite often what we need to do depends on what the chemical is. So keep in mind what chemicals you are working with. With spilled acids, sodium bicarbonate (any brand) is often a good neutralizing agent.

Handling chemicals requires care and several techniques that I'd better mention.

First, never handle any laboratory chemicals with your fingers--some stain, and some are corrosive. Instead, for the solids you can use a clean scoop.

Whenever you remove the lid of a bottle containing a chemical (whether it's a solid or a liquid), either hold the stopper or lid in your hand or put it upside down on the counter to avoid contaminating the stopper or lid, which in turn would contaminate the chemical in the bottle. Of course, a dirty lab scoop will certainly contaminate the bottle. To be sure the lab scoop is clean, always wash and dry it before you use it.

Another technique for transferring solid chemicals is to pour from the bottle onto a folded piece of paper and then pour it from the paper into the test tube (or whatever container you are using). In that way you avoid contaminating the chemical in the bottle. Once you have removed a chemical from a bottle, you should replace the lid securely. Also, do not return chemicals to a bottle once you have removed them. It's better to waste a little bit of that material than to waste the whole bottle because it has been contaminated. A corollary to this is to not take any more chemical than you need. You can always take more later if you need it.

When disposing of used chemicals, first look for special "waste" containers designated for that chemical. In the absence of a special container, put solids that don't dissolve in water into the wastebasket, not the sink. That includes matches. Don't throw matches in the sink. Make sure they are out, wet them, and then look for a container that says "used matches"; there will often be one on the counter near the burners.

Liquids and solids that are soluble in water can sometimes be disposed of in the sink, and washed down with plenty of water. But first check to see if there is a special waste container for them. Ask the instructor if you aren't sure what to do with a particular chemical.

Of course, be sure to wash out all your equipment so that the next person doesn't have to start with a big mess.

The safety precautions and lab techniques are also listed for you in Example 0 so that you will have those readily available for your reference.

 

 

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