Chapter 3: Equipping a Home Chemistry Laboratory 15and some rubber or plastic tubing, you can convert a test tube
into a miniature gas-generating apparatus or distilling setup or
reaction vessel. Inverted in a pan of water, a test tube can be used
to capture gases. With a solid cork or rubber stopper, a test tube
serves to store samples. You can probably imagine many other
uses without much effort.
Test tubes are readily available in sizes from 10×75 mm to
25×200 mm. For general use, the best sizes are 15×125 mm,
which holds 14 mL, 16×150 mm (20 mL), or 18×150 mm (27 mL).
One nice thing about test tubes is that they’re cheap. High-quality
test tubes in standard sizes sell for $4 to $6 a dozen, and there
are often significant discounts for buying larger quantities. That
means that you needn’t worry about damaging test tubes, as
you might with more expensive glassware. You can abuse your
test tubes when necessary, and treat badly soiled test tubes as
disposable. A dozen test tubes is a good starting point for a
home lab.BARSE kE
Beakers are among the most commonly used items of laboratory
glassware; they’re used when test tubes aren’t large enough.
Beakers are flat-bottomed, cylindrical containers, usually
equipped with a pouring spout, and are used for routine
mixing, measuring, heating, and boiling of liquids. Beakers are
available in glass (usually Pyrex or a similar borosilicate glass),
polypropylene, and other materials, and are available in capacities
from 10 mL to 5,000 mL (5 L) or more.Polypropylene beakers are popular because they are unbreakable,
but they cannot be used for heating or boiling liquids and they
may discolor or become cloudy when used with some organic
solvents or strongly colored compounds. PolypropyleneWe use student-grade glassware in this book, solely for cost
reasons. For example, we paid $1.80 for one Chinese Bomex
student-grade flask. Similar name-brand laboratory grade flasks
made of Pyrex or Kimax cost two or three times as much. If
budget is not an issue, buy laboratory-grade glassware. But if the
budget is tight, don’t hesitate to buy student-grade labware.
TSTTBESE U
For most people, the test tube (shown in Figure 3-2) is the one
piece of equipment that defines a chemistry lab, and rightly so.
Test tubes are used so often and for so many purposes that it’s
hard to imagine a chem lab without them. Most of the time, you’ll
use test tubes to mix solutions, heat samples, observe reactions,
and perform other similar tasks. But test tubes have many other
uses. With a one- or two-hole rubber stopper, a glass tube or two,
BREFULCE A WITH ALL GLASSWARE
Even the best glassware can shatter unexpectedly,
particularly if it is heated very strongly or if when hot
it contacts a cold liquid. Inexpensive, student-grade
glassware is more likely to shatter, because it may use
thinner glass and may not be annealed as well as more
costly name-brand glassware. Such accidents are very
unlikely, even with inexpensive glassware, but you should
always keep the possibility in mind. When you work with
glassware, and particularly if you heat it, always wear
splash goggles and protective clothing.z
HomCE HEmISTRy oN A BUdGET
If you’re on a very tight budget, consider ordering the $36
Basic Chemistry Equipment Kit (CE-KIT01) from Home
Science Tools. This kit contains an assortment of essential
glassware and hardware for a home chem lab, including
an alcohol lamp and tripod stand, 250 mL and 600 mL
beakers, a 250 mL Erlenmeyer flask, 10 mL and 100 mL
graduated cylinders, a funnel, test tubes, a test tube rack
and holder, an eye dropper, a stirring rod, a thermometer,
rubber stoppers, glass and plastic tubing and a pinch
clamp, and a vial of pH indicator paper (http://www.
homesciencetools.com).
This kit contains many of the items you need to complete
the laboratory sessions in this book, although you’ll
need to supplement it with other individual items, either
purchased or homemade. (See the lists of glassware and
equipment for some ideas.)FIGURE 3-2: Test tubes in a test tube rack