Chemistry Reference
In-Depth Information
Chapter 14 Organic chemistry 1
●
Demonstrate combustion of some alkanes. Use a
Bunsen burner to show complete and incomplete
combustion of methane. Burn a range of alkanes to
show the variation in ease of ignition - pentane and
hexane are highly flammable but liquid paraffin and
paraffin wax need pre-heating and/or a wick.
●
Reaction of alkenes with bromine.
●
Cracking of alkanes as described in the text
(Figure 14.11, p. 224).
●
Test for unsaturation using bromine in a suitable
solvent (Figure 14.13, p. 225).
●
Demonstration of thermosoftening and
thermosetting plastics. Heat small samples of
poly(ethene) and melamine.
●
Reaction with bases - sodium hydroxide
solution, copper(ii)
ii
) oxide and magnesium oxide.
●
Reaction with an indicator - litmus.
●
Show that ethanoic acid is a weak acid - a
comparative study with hydrochloric acid.
●
Measure the pH of 0.1 mol dm
−3
solutions of
both acids.
●
Measure the conductivity of 0.1 mol dm
−3
solutions of both acids.
●
Measure the time taken for a short length of
magnesium ribbon to react with 1.0 mol dm
−3
solutions of both acids.
●
Formation of esters (p. 237).
Soaps and detergents
●
Making soap from vegetable oil and alkali. Boil a
vegetable oil or animal fat with aqueous sodium
hydroxide. Cool and add salt to precipitate the
soap.
●
Preparation of a soapless detergent from a
vegetable oil.
Amino acids
●
Identification of amino acids by chromatography.
Use a 4 : 1 : 2 mixture of butanol, ethanoic acid
and water as a solvent. Dry the chromatogram and
develop with a ninhydrin spray.
●
Biuret test for proteins. Warm the sample in water,
add concentrated sodium hydroxide solution and a
drop of very dilute copper(ii)
ii
) sulfate solution.
Plastics and polymers
●
The 'nylon rope trick'. The diamine,
1,6-diaminohexane, is dissolved in water to
which some sodium carbonate has been added. A
solution of a diacid chloride, adipoyl chloride, in
cyclohexane is added and a nylon thread can be
pulled from the interface between the two phases.
●
Making a solid foam. The ingredients for making
a polyurethane foam can be purchased as a
demonstration kit.
Chapter 15 Organic chemistry 2
Ethanol
●
Combustion of ethanol in a small spirit lamp to
demonstrate that it burns with a small blue flame.
●
Add ethanol to water to show that the two liquids
are miscible.
●
Show examples of ethanol as a solvent.
●
Oxidation of ethanol by the air. Use a water pump
to bubble air through dilute aqueous ethanol.
R
●
Add ethanol dropwise to a warm mixture of
potassium dichromate(
vi
) and dilute sulfuric acid.
R
●
Formation of esters using ethanol and higher
alcohols. Mix 1 cm
3
of ethanol and 1 cm
3
of glacial
ethanoic acid. Add 2 drops of concentrated sulfuric
acid and warm the mixture for a few minutes. Then
pour the mixture into a beaker of cold water. The
distinctive smell of an ester can be detected. Repeat
the procedure using higher alcohols - propanol,
butanol and pentanol.
●
Making ethanol by fermentation (Figure 15.8,
p. 236).
●
Fractional distillation of a mixture of water and
ethanol, using the apparatus shown in Figure 2.22
(p. 21). Note that this procedure may be illegal in
some countries.
Starch and glucose
●
Tests for starch and glucose. Test for starch
using dilute aqueous iodine and for glucose with
Fehling's solution or Benedict's reagent.
●
Hydrolysis of starch (p. 242). Use the tests above
to show that glucose is formed and starch is used
up when aqueous starch is boiled with dilute
hydrochloric acid.
Ethanoic acid
●
Show that ethanoic acid is an acid.
●
Reaction with metals - magnesium and zinc
powders.
●
Reaction with carbonates - aqueous sodium
carbonate and copper(
ii
) carbonate.
