Heating mantles are the primary heat source for reactions using round bottom flasks as the reaction vessel. Mantles have a hemispherical interior, allowing the flask to nest inside. This provides direct, even heat to a large surface area of the flask.

Heating mantles are sized specifically for different sizes of round bottom flask, and the mantles used in the organic chemistry labs are 100-mL. Smaller flasks (specifically, 50-mL flasks) will also fit these mantles, but the mantle should be packed with glass wool to assure even heating and minimal heat loss.

There are two different models of heating mantles used in the organic chemistry labs: Unimantles (which are blue) and Thermowells (which are gray).

Unimantles have mesh-lined interiors which may, over time, deteriorate. When making a sand bath, do not pour sand directly into the Unimantle cavity -- hot sand falls through the mesh and has a tendency to melt the innards (use an evaporating dish to hold the sand instead, and place the evaporating dish in the Unimantle cavity). One advantage to the Unimantle design, though, is the rear brace: it can very easily be directly attached to a support stand.

Thermowells, on the other hand, are lined with a chemically-inert resin which increases their longevity and safety, and you may safely pour sand directly into a Thermowell cavity with no problems.

The mantles are stored in the locked equipment cabinets in the lab rooms, and your TA has the key. Each mantle is packed in a cardboard box with a control unit, which is used to regulate the heat output of the mantle. The stockroom has several larger heating mantles available for check-out if you need to work with larger-sized flasks.

Note: heating mantles and power units are subject to electrical failure due to blown fuses or corroded wiring. If you are using any piece of electrical equipment you suspect is not working properly, please bring it to the stockroom!

Hot plates are the other main heat source used in the organic chemistry labs, being used primarily to heat flat-bottomed vessels such as beakers and Erlenmeyer flasks.

The hot plates used in the organic chemistry labs feature white ceramic top plates which become stained easily by solutions which boil over -- so please use caution when heating any solution, and please clean all surfaces of the hot plate after use.

Hot plates are stored in the locked equipment cabinets in the lab rooms, and your TA has the key. In the past, students have demonstrated carelessness by coiling the power cord and setting it on top of a hot plate that in fact is still hot enough to melt right through the cord, destroying the cord and sometimes damaging the hot plate in the process. You must take extra care to ensure you store the hot plate properly and carefully after use, by correctly coiling and binding the power cord and storing it separately from the hot plate, in the bins inside the equipment cabinet specifically designated for their storage.

A stir plate, sometime called a "stir motor", rotates a magnet directly underneath its top plate. Together with a small stir bar, it is used to agitate a solution.

A stir bar, which is a small magnet coated with an inert substance (usually teflon), is added to the solution to be stirred. When the stir plate is turned on, the stir bar attracted to the stir plate magnet rotates in concert with the stir plate magnet, mixing the solution.

Stir plates are stored in the locked equipment cabinets in the lab rooms, and your TA has the key. Stir bars are available for check-out from the stockroom.

Mel-Temps are the devices used to assess the purity of a prepared solid sample by measuring its melting point. You use a Mel-Temp by first placing a small amount of the substance to be tested in a capillary tube, compacting it, then placing it in the Mel-Temp along with a thermometer, and turning on the power. This technique is covered in much greater detail in the first few weeks of your lab course.

The OCS is currently trying to discontinue the use of mercury-filled thermomemeters in the taching labs, for safety reasons. The primary use of the high-temperature thermometer is for the determination of melting points, so we have devised an alternative method of doing this. Several of the Mel-Temps have been fitted with copper tubes to allow the use of a special temperature probe which is inserted into the Mel-Temp in much the same was as a thermometer. The temperature probe features a digital read-out which displays the temperature. If you need a temperature probe, they are stored in the equipment cabinets. Please consult your TA, or OCS staff, for details on using the temperature probe if you have any questions.

There are eight Mel-Temps in each lab room, permanently affixed to the counter along either the north or the south wall. Capillary tubes are available at the stockroom window.

Note: Mel-Temps get very HOT, so use caution and follow your TA's instructions very carefully to avoid burning yourself when using a Mel-Temp.

Also note: Mel-Temps have several electrical components (fuse, bulb, etc.), any one of which may be in need of repair. If you see a Mel-Temp which you suspect is malfunctioning or broken in any way, please notify the stockroom.

Centifuges, with their accompanying centrifuge tubes, are used to:

• clarify nonsettling solutions containing finely divided solids,
• break emulsions of two immiscible liquids,
• collect solids from a slurry,
• obtain a clear solution from a liquid-solid mixture, and
• separate two immiscible liquids from each other.

There are three centrifuges located in each of the lab rooms, next to the Mel-Temps on the counter on either the north or the south wall. Our centrifuges feature built-in timers, and also a safety feature which prevents the rotor head from spinning until the cover is locked shut.

Note: there are several rules to follow when using a centrifuge:

1. Always use balanced pairs of centrifuge tubes which are placed opposite each other on the rotating head. If there is only one tube, counterbalance it with another tube containing an equal volume of water.
2. Always use only capped centrifuge tubes; others may break.
3. Always close the centrifuge cover before you start the motor, and open it only after the assmbly has stopped spinning.
4. Always turn off the centrifuge if vibration develops. Tubes may have broken, their contents may be lost, and the rotor head may have become unbalanced. Never use your hands to stop the machine.

The vortex mixer is a handy device for quickly mixing a small amount of solution. To operate the vortex mixer, simply press the bottom end of a capped test tube or a capped centrifuge tube (or even a small, securely stoppered Erlenmeyer flask) against the rubber pad on the top of the vortex mixer. The pad will begin to "vibrate" (actually it moves incredibly quickly in a very small circle) causing the solution in the tube or flask to become almost immediately agitated.

Although the vortex mixer is a small piece of equipment, it is pretty effective when mixing. So much so that if you make the mistake of using the vortex mixer with an open test tube or flask, the solution will immediately splash right out. This might make for a rather impressive display, but this careless act could have very harmful or severe consequences. Therefore, always make sure you use only capped or securely stoppered tubes or flasks with the vortex mixer.

There is one vortex mixer located in each of the lab rooms, next to the centrifuges, on the counter along either the north or the south wall.