Chapter 3 Hazardous materials
School Science Laboratory Safety Regulations
iv.
Procedures that involve volatile chemicals or may result in the release of airborne contaminants should be performed in a chemical fume cupboard. This includes the weighing of hazardous chemicals.
V.
Hands must chemicals.
be
thoroughly
washed
after
any
contact
with
Concentrated acids b.
Proper protective equipment (protective gloves, safety goggles and laboratory coats) must be worn when handling concentrated acids. Work should be carried out in a fume cupboard. Any contact of the chemical with the skin should be washed with plenty of water immediately.
c.
When diluting acids, always add the acid slowly to water, never water to the acid. Mixing with water produces heat, which may result in splashes or the formation of hazardous mists.
Concentrated ammonia d.
Work involving concentrated ammonia must be performed in a fume cupboard as ammonia vapour is highly pungent, severely irritating and tear-inducing. Proper protective equipment must be worn.
e.
Bottles containing concentrated ammonia should with care as pressure may accumulate inside the bottles.
be
opened
Hydrogen peroxide f.
Hydrogen peroxide is a strong oxidiser. Although pure hydrogen peroxide is fairly stable, it decomposes into water and oxygen (which in turn supports combustion) when heated above about 80째c. It also decomposes in the presence of catalysts like most metals and acids'
g.
It is advisable to put on gloves and safety goggles when handling hydrogen peroxide as it irritates the skin and can cause eye burns.
Metals - mercury h.
Mercury can be found in liquid-in-bulb thermometers. Mercury must not be used as a chemical in school laboratories. The vapour is poisonous in concentrations as low as 1 ppm.
i.
Mercury spills usually arise from broken mercury-filled thermometers. Spills should be cleared by the teacher or a laboratory staff member. Mercury droplets can be collected, for example, using a capillary tube or dropper. Any remaining traces of mercury should be covered with sulphur to produce a
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