Illustrated Guide to Home Chemistry Experiments

Chapter 3: Equipping a Home Chemistry Laboratory 33

Various accessories are available, including stands and

heat spreaders, that make these burners very useful in a

home lab.

Hotplate
As useful as alcohol lamps and gas burners are, there are
times when you need a heat source that doesn’t use flame.
An open flame can be very dangerous, particularly if you are
working with a flammable liquid or gas. For those situations,
the best solution is an electric hotplate. The best models have
electronic controls and are specifically designed for laboratory
use. Many laboratory hotplates also include a built-in magnetic
stirrer, which can be very useful. Unfortunately, laboratory
hotplate/stirrers aren’t cheap. Fortunately, an ordinary
kitchen hotplate is inexpensive and serves the purpose
nearly as well.

SPPORTU STAnDS, RInGS, AnD CLAMPS
A ring stand, also called a support stand, is a heavy metal base,
usually of cast iron, that supports a vertical rod to which various
rings and clamps can be attached. Ring stands vary in price,
construction quality, base size, rod diameter and length, and
other factors, but essentially any ring stand is suitable for use in
a home chem lab.

Support rings are generally made from cast iron or steel, and
are available in various diameters. Some require a separate
clamp to attach them to the stand, but most include a built-
in clamp. A ring is not normally used alone when heating a
container. For heating flasks and beakers, a wire gauze with a
ceramic center is used between the ring and the base of the
container to spread the heat evenly. Figure 3-22 shows a ring
stand with ring and wire gauze.

AvOIDO PEn FLAMES

If you are working with any flammable liquid or gas,

never use an alcohol lamp, gas burner, or any other

heat source that produces a flame. No matter how

careful you are, a catastrophic fire or explosion could

occur without warning.

z

FIGURE 3-21: A butane microburner with fuel

A ring stand and ring are also useful to support a filter funnel

or sep funnel.

Crucibles are designed to be used at very high temperatures,

and are normally heated by a gas flame directly on them.

Despite their temperature resistance, crucibles are relatively

fragile physically, and might fracture if supported directly by

a metal ring. Instead, as shown in Figure 3-23, a ring is used

to support a clay triangle, which in turn supports the crucible.

The crucible contacts only the clay pipes, which insulate it

from rapid temperature changes that could cause it to crack.

In addition to rings, various types of clamps can be connected

to the support rod. These clamps are used to secure glassware

and any other apparatus to prevent them from tipping over or

coming apart during a procedure. Among the most useful of

these is the general-purpose utility clamp, shown in Figure 3-24,

which is used to secure flasks, test tubes, and other glassware.

Other general-purpose clamps include right-angle clamps

and adjustable-length clamps. A thermometer clamp can be

used for its nominal purpose, but is also useful for securing

glass tubing. A three-finger clamp is usually used to support

a separatory funnel, but is also useful for other purposes. A

FIGURE 3-22: A ring stand with a ring and wire gauze