Do not let equipment such as power stirrers hot

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Unformatted text preview: ght or at other times are prime sources for fires, spills, and explosions. Do not let equipment such as power stirrers, hot plates, heating mantles, and water condensers run overnight without fail-safe provisions and your instructor’s consent. Check unattended reactions periodically. Always leave a note plainly posted with a phone number where you and the instructor can be reached in case of emergency. Remember that in the middle of the night, emergency personnel are entirely dependent on accurate instructions and information. 9 students short index 1/15/03 12:45 PM Page 10 2. Guide to Chemical Hazards Chemicals can cause harm if they are not handled properly. For example, they can be toxic, flammable, corrosive, or reactive. Some chemicals are hazardous in only one of these ways, some in more than one. Every chemical, even water,3 is hazardous in at least one way. The degree of hazard varies; it can be great or small, or in-between. For example, both gasoline and alcohol are flammable, but gasoline is much more flammable. Gasoline is easier to ignite and more likely to burn vigorously or explode than alcohol. In all cases, you can work safely by taking the precautions that are described on the label and in the Material Safety Data Sheet (see page 12). The instructor in charge of your laboratory can explain the precautions that you will follow in your laboratory work. Toxicity This discussion is a brief introduction to the topic of toxicity. It has long been known that anything ingested in sufficient quantity can be lethal. In the 16th century, a military surgeon and alchemist known as “Paracelsus” (whose real name was Philippus Aureolus Theophrastus Bombast von Hohenheim) wrote: “What is it that is not poison? All things are poison and nothing is without poison. It is the dose only that makes a thing not a poison.” Any substance could be harmful to living things. But complex relationships exist between a substance and its physiological effect in humans. The major factors include the dose (the amount of a substance to which one is exposed and the length of time of exposure to the substance), the route of exposure (by inhalation, ingestion, absorption through the skin or eyes, or injection), and myriad other factors such as gender, stage in the reproductive cycle, age, lifestyle, previous sensitization, allergic factors, genetic...
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This document was uploaded on 02/27/2014 for the course PHYS 1B at UCSD.

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