Illustrated Guide to Home Chemistry Experiments

52 DIY Science: Illustrated Guide to Home Chemistry Experiments

Many packaged chemicals display one or more of the following
pictograms and/or letter symbols to alert the user to specific
hazards posed by that chemical.

These pictograms are intended to provide only general guidance.
For additional information about the specific hazards involved
and the steps required to handle the chemical safely, read the
MSDS or other detailed safety information.

SAfE CHEmICAL HANdLING

It’s important to treat your laboratory chemicals with respect and to handle them safely. But

it’s also important to realize that everyone routinely deals with many potentially dangerous

chemicals, and that injuries occur only when those chemicals are mishandled.

For example, your bathroom medicine cabinet may contain
isopropanol (flammable), ethanol (flammable), acetone nail
polish remover (flammable), acetaminophen (toxic), tincture of
iodine (toxic, flammable), and various prescription drugs (toxic).
That can of crystal drain cleaner under the sink is almost pure
sodium hydroxide (corrosive, toxic). Your automobile contains
several gallons of gasoline (flammable), and its battery contains
sulfuric acid (corrosive, toxic). If you use a wire brush to clean the
terminals on your car battery, that powder you’re scraping off is
lead sulfate (toxic). You probably have a gallon of chlorine bleach
(toxic, corrosive, oxidizer) in your laundry room, and the shelves
in your basement shop probably hold cans of paint thinner
(flammable), turpentine (flammable), and perhaps a gallon of
concentrated hydrochloric (muriatic) acid (toxic, corrosive)
for cleaning concrete. Your garden shed is probably full of
insecticides (toxic) and that 50-pound bag of 34-0-0 fertilizer is
actually pure ammonium nitrate (oxidizer, explosive). There may
even be an old container of arsenic-based rat poison (toxic). Old
thermometers contain mercury (toxic), as do fluorescent tubes.
And so on.

The point is this: we are all exposed regularly to potentially
hazardous chemicals, but awareness of the dangers and proper
handling minimizes the risk of injuries. Use common sense
precautions when handling chemicals. Wear gloves and protective

clothing when handling chemicals, and always wear splash

goggles. If you are working with powdered chemicals, wear a

respirator mask. Have a fire extinguisher and first-aid kit handy.

Respect your chemicals. Do not fear them.

INCompATIBLE CHEmICALS

Some chemicals are incompatible with each other, in the

sense that combining those chemicals may result in a violent

or dangerous reaction such as intense heat, fire, explosion, or

release of a toxic gas. In other cases, the reaction may not be

immediately obvious. For example, by combining some

chemicals you may unintentionally create a shock-sensitive

explosive such as a peroxide or a fulminate, which might later

detonate unpredictably.

Of course, sometimes such incompatible chemicals are

intentionally combined to cause a reaction, but it’s important that

you avoid doing so unintentionally. If you’re expecting spectacular

results, you can take steps to deal with them safely. If you’re not

expecting a violent reaction, the results can be tragic.

Table 4-1 is a matrix that lists general incompatibilities between

classes of chemicals. The matrix is not exhaustive. For example,

the matrix lists organic acids, organic poisons, organic solvents,

HAzARd pICToGRAmS ANd LETTER SymBoLS

n

i

Caustic/

Corrosive

Explosive

Flammable

Harmful

Irritant

Harmful to the

environment

Oxidizing

Toxic