Chemistry Reference
In-Depth Information
Experiments
In Chap.
8.2,
many reactions of different household chemicals are described already
so that the “problem” and even the “explanation” are given with those
interpretations. Therefore, the paragraph “problem” will not be shown in the
following short instructions - only the “procedure” is given. Because the “material”
consists mostly of some test tubes, this paragraph is also removed.
E8.1 Tab Cleaner “NaOH Type” Put a spoon of the cleaning powder on a watch
glass and observe white salt crystals and silver-colored metal splinters. A
part of the substance is mixed with a small amount of water in a test tube: an
exothermic reaction begins and a smell of ammonia is noticeable. Pieces of
wool fabric are added: they decompose slowly.
In a second experiment, pure sodium hydroxide is mixed with aluminum
shavings and little water, the produced gas is collected in a second test tube.
After igniting the gas, a little bang is observed: the produced gas is hydrogen.
E8.2 Toilet Cleaner “HSO
4
Type” A small amount of substance is given in a test
tube, white salt is observed. It is dissolvedinwater,thesolutionisexaminedwith
universal indicator paper: acidic reaction. A small amount of calcium carbon-
ate is added to the solution: the sample will be dissolving with gas develop-
ment. A burning wooden splint is extinguished: the gas is carbon dioxide.
E8.3 Sanitary Cleaner “ClO
Type” Cleaner liquid is given into a test tube, a strip
of indicator paper is dropped, some drops of methyl blue solution are added:
indicator paper turns white, blue solution turns colorless.
A second sample is mixed in a test tube with toilet cleaner (E8.2): the smell
and color of the developing gas indicate chlorine (dilute the solution in the
vent to stop the reaction).
E8.4 Deodorant “Al
3+
Type” One brand of deodorant is Hydrofugal spray. Indi-
cator paper is moistened: acidic reaction. Little aluminum chloride hexahy-
drate is dissolved in water (test tube) and examined with indicator paper:
acidic reaction.
E8.5 Mineral Tablets “Ca
2+
and Mg
2+
Types” One tablet is given into a glass of
water: gas bubbles, formation of carbon dioxide. The reaction is repeated
with a mixture of calcium carbonate and citric acid, water is added.
In a gas developer, water is dripped on a tablet, the developed gas is
collected in a syringe. As soon as the 100 mL mark is reached, the
gas is moved out and new developed gas is collected again. The quantity
of gas is determined; the gas is examined with a burning splint.
The reaction of one tablet is performed in a pneumatic tub, in such a way that
the gas is collected in a water filled cylinder. The volume will be marked. A
second tablet will be dissolved in the same way: the observed volume of the gas
portion is much larger than previously with the first tablet (compare with E2.3).
E8.6 Table Salt “Iodine Type” Ingredients of the salt will be checked on the label
of the container. Iodinated table salt will be mixed with potassium iodide
solution and acidified with sulfur acid solution: brown-colored iodine
