McMaster University - Chem2O06 Lab Manual 1997/98


A chemical laboratory is potentially a dangerous place, and safety precautions should be the concern of everyone who works in one. The following notes are provided to assist you in avoiding unnecessary accidents, and to indicate the action to take should an accident occur. Study this material carefully.

Safety Equipment

There is an emergency shower in each laboratory. These are for use when corrosive liquids have spilled over large areas of clothes and skin, and when clothing is afire. Become familiar with the location of these showers.

Fire Blankets.
Fire blankets are located in Rooms 117, 201, 214, and in the 1st floor corridor, beside the Chemistry Store (Rm 125). If clothing is on fire, the first thing to do is get the victim to the floor (to reduce damage to hands, face, eyes and respiratory system). The victim should be rolled over and over to smother the flames, using the fire blanket or a lab coat.

Fire Extinguishers.
Know the location of the fire extinguishers in your laboratory and read the directions for their operation. They are very effective for fires involving organic liquids and electrical wiring. Small fires in test tubes, beakers, etc., can usually be smothered by covering with a heat resistant mat.

Fire Alarms.
Are located in all corridors near corridor and building exits.

Chemical burns do not often become serious if the affected part is washed promptly and thoroughly with water. Water ­­ lots of it ­­ is the first treatment for all accidents in which corrosive chemicals have been spilled or splashed on external skin surfaces.

Eye-wash Fountains
Learn the location of the eye-wash fountain in your lab. In the event that a chemical has been splashed into the eyes, immediate action must be taken to prevent damage to the sensitive tissues in the eyes. The victim (with assistance if it is available) should wash the eyes with water for at least 10 minutes. Roll the eyeballs to ensure thorough washing. Seek medical attention immediately.

Safety Glasses or Goggles.
These must be worn at all times in the laboratory. Contact lenses are not permitted in the Chemistry 2O06 laboratories. Chemicals splashed into the eyes can be very difficult to wash out with contact lenses present and may cause bonding of the lens to the eye. Also, solvent vapours are absorbed by soft contact lenses and can cause irritation. Any student not wearing safety glasses or goggles will be required to leave the lab immediately.

Lab coats are strongly encouraged. Sandals are not permitted in the lab. Loose or long hair must be tied back. Shorts and skirts should not be worn. Clothing or unnecessary books must not be left around the lab.

Face Shields.
The use of face shields is recommended when high vacuum distillations are being done in glass equipment and when there is a high possibility that a violent reaction can occur. While these shields can be obtained from the Technician, they will not be necessary for the Chem 2O06 labs.

Sand Pails.
The sand, in pails in each of the laboratories, is for smothering small fires. It is particularly useful for sodium or potassium fires.

First aid Kits.
First Aid drawers are in each laboratory. Become familiar with their location and contents. In the event of an injury report to a TA who will take the necessary action. Do not neglect even small cuts or burns. These can become very serious if they are not treated promptly and properly. The first treatment for burns is ice or cold water.

Spill Kits.
Spill kits are provided in each lab room for use in the event of a chemical spill. Know their location and how to use them.

Scott Air Packs.
These are breathing apparatuses which are TO BE USED BY TRAINED PERSONNEL ONLY. There is one located on the 1st floor beside the Chemistry Stores (Room 125) and on the 2nd floor, near the elevator.

Safety in Laboratory Operations

Handling of Glassware

Accidents occur every year from the careless handling of glassware. These result in considerable inconvenience and loss of time, not to mention pain. Accidents of this type can be avoided by observing the following rules.

Fire­polish the ends of all glass tubing and glass rods.

Before inserting a thermometer or glass tube into a stopper or rubber tube:
i) Be certain the hole is large enough to accommodate the glass.
ii) Lubricate the glass and the rubber with glycerol or stopcock grease.
iii) Protect your hands by holding the stopper and the glass in towels. Hold the stopper by your fingers NOT IN THE PALM OF YOUR HAND.
iv) Grasp the glass close to the end that is to fit into the stopper and twist with an even pressure.

Do not attempt to push or pull glass tubing or thermometers from rubber tubing, corks or stoppers which have become hardened. Cut the rubber or cork from the glass.

Do not try to force an oversized stopper into a flask or bottle. Use the proper size stopper.

When picking up a beaker, the fingers should be placed around the outside, not over the rim. If the beaker is hot, use tongs.

Never point test tubes at your neighbour or yourself when heating substances.

Handling of Chemicals

All bottles containing chemicals should be plainly and clearly labelled. Materials found in unlabelled bottles should be returned to the Chemistry Stores (Rm 125).

Flammable, volatile liquids such as alcohol, ether, benzene, etc., must never be distilled or evaporated over an open flame. Furthermore, there must not be an open flame in the neighbourhood of such operations. A column of flammable vapour can be wafted towards a lighted burner ten feet or more away and become ignited to strike back to the flask or bottle containing the flammable liquid and set it afire.

Be careful always to keep all bottles and flasks, containing flammable and volatile liquids, well stoppered, and never open them near a flame. Care should also be exercised in preventing these flasks or bottles from becoming heated by steam pipes or other sources of heat, since the internal pressure may become sufficient to blow out the stopper. Careful attention should be given to such sources of ignition as sparking brushes from electric motors and exposed heating elements.

Material Safety Data Sheets.
Most chemical reagents are potential hazards. Any chemical is injurious if a sufficient quantity enters the body. Proper methods of handling, adequate precautions, and a knowledge of protective measures and first aid should be learned NOW. Otherwise, the penalty may be impaired health and a shortened life. Material Safety Data Sheets on all chemicals employed in the Chem 2O6 labs are provided in the lab rooms, and the web page contains a link to a larger list. Refer to these if you have questions about the toxicity or characteristics of any chemical.


Waste chemicals or broken glass placed in regular garbage bins can cause injury to the persons required to dispose of that garbage. For this reason all laboratory waste must be put in the appropriate container.

CLEAN WASTE (bin near each large sink).
Items such as paper towels, J­cloths, corks, rubber stoppers, plastic vials and filter papers can be put in the regular garbage after they have been cleaned of all chemicals.

GLASS (plastic pails labelled for glass disposal).
All waste glass (with the exception of thermometers containing mercury, unknown sample vials and melting point capillaries and slides) must be placed in glass disposal bins. The glass must be clean.

BROKEN THERMOMETERS (fume cupboards).
Labelled containers are provided in the fume cupboards for broken thermometers which contain mercury.

SAMPLE VIALS (fume cupboards).
Dispose of any chemical remaining in the vial (use the proper waste container) and place the empty vial in the labelled container located in the waste fume hood.

Labelled containers are provided in the fume cupboards for used melting point capillaries and cover slides.

CHEMICAL WASTE (fume cupboards).
Labelled bottles are provided in the fume cupboards for the disposal of all chemical waste. The bottles are labelled for the following categories of chemical:


It is extremely important that all waste go into the proper container. Injuries have resulted in the past from the careless mixing of chemical waste. If you have any questions consult your T.A. before proceeding.

Common Sense

Eating, Drinking or Smoking are not allowed in the laboratory.

Horseplay, stunt experiments, or experiments not assigned are strictly forbidden in all laboratories. The Department has the right to banish an offender from the laboratories.

Cleaning Solutions
Cleaning solutions of the sulfuric acid ­ dichromate type should be treated with respect. Any splattering will destroy clothing and quickly produce painful skin burns. Under no circumstances should nitric acid be used to clean vessels that contain organic material, because an explosion or a fire may ensue.

Water or Chemical Spills.
Water or chemicals spilled on the floor must be mopped or cleaned up promptly. Spill Kits are provided in each laboratory for the neutralization of spilled chemicals. Never leave an apparatus containing corrosive materials around where someone might be burned. When diluting an acid, pour the acid into water. NEVER POUR WATER INTO AN ACID.

Good Technique.
The attention you pay to using good, safe techniques in assembling apparatus and in carrying out laboratory operations greatly reduces the possibility of accidents. An important aspect of good technique is cleanliness. If the student who used your work station before you put away the clamps, hot plates, heating mantles, etc., you would find it much easier to perform your experiment and there would be less chance of an accident occurring. Keep this in mind as you clean up your area before leaving the lab.

Working unsupervised.
No undergraduate student is permitted to work in any laboratory unless a teaching assistant is present.

Always wash your hands before leaving the laboratory.

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