Chemistry Reference
In-Depth Information
Metallic bonding
●
The properties of typical metals will be covered
by the practical work on the transition elements in
Chapter 9.
that in Figure 5.2 (p. 72), but with an ammeter
in preference to the lamp, and measure the
conductivity of a selection of liquids, for example
sodium chloride solution, hydrochloric acid,
sodium hydroxide solution, water, dilute ethanoic
acid, aqueous ammonia, paraffin and ethanol.
●
Electrolysis as decomposition, for example of
copper chloride solution, zinc bromide solution,
hydrochloric acid and acidified water. Include tests
for chlorine, oxygen and hydrogen.
R
●
Electrolysis of aqueous solutions of the following
using inert electrodes: sodium chloride, copper(ii)
ii
)
sulfate, sodium sulfate and sodium hydroxide.
●
Electrolysis of aqueous copper(ii)
ii
) sulfate using
copper electrodes.
●
Examples of electroplating, such as nickel plating.
Use a nickel anode, a copper cathode and nickel
sulfate solution as the electrolyte in a cell similar to
that in Figure 5.20 (p. 84).
Chapter 4 Stoichiometry - chemical
calculations
Moles and gases
●
Measure the molar volume at rtp for hydrogen.
Use a flask with a delivery tube and collect the
gas over water in an inverted measuring cylinder
or burette (Figure 16.2). Put an excess of dilute
hydrochloric acid, say 100 cm
3
of 2 mol dm
−3
acid,
in the flask and add a piece of magnesium ribbon
whose mass is known accurately and is about 0.1 g.
(It is useful to measure the mass of a 1 m length of
ribbon and then the mass of a smaller length can
be calculated.) Measure the volume of hydrogen
collected in the measuring cylinder or burette.
Chapter 6 Chemical energetics
●
Simple distillation of a synthetically manufactured
'crude oil' obtained from chemical suppliers.
●
Inspection of some of the fractions of the primary
distillation of crude oil - colour, viscosity, boiling
point and flammability.
●
Show examples of exothermic and endothermic
reactions.
●
Dissolve ammonium nitrate in water - an
example of an endothermic change.
●
Dissolve anhydrous copper(ii)
ii
) sulfate in water -
an example of an exothermic change.
●
Determination of the enthalpy of combustion of
ethanol, as described in question 6 on p. 102.
●
Show that the reaction between zinc and copper(ii)
ii
)
ions is exothermic.
●
Add zinc dust to copper(ii)
ii
) sulfate solution. Note
the temperature of the solution before and after
the addition of the zinc. Here chemical energy is
transformed into heat energy.
●
Set up a zinc/copper cell and note its polarity
and voltage (Figure 6.23, p. 98). Here chemical
energy is changed into electrical energy. Repeat
using other cells, for example Cu/Ag, Fe/Cu
and Mg/Cu. This will demonstrate that the
reactivity series can be established using cells.
R
●
To simulate a fuel cell, electrolyse water for a few
minutes until both electrodes are covered with
bubbles of gas. Replace the power supply with a
voltmeter. This will show that the cell produces a
hydrogen
collects
here
lift the cork slightly
and immediately replace;
magnesium falls into acid
measuring
cylinder
cotton thread
water
magnesium
ribbon
excess dilute
hydrochloric
acid
Figure 16.2
Measuring the molar volume of a gas at rtp.
●
Measure the molar volume at rtp for carbon
dioxide. Repeat the experiment above, using a
known mass of a carbonate and collecting the
carbon dioxide in a syringe.
Chapter 5 Electricity and chemistry
●
Introductory practical. Electrolytes only conduct
in the liquid phase, either molten or in aqueous
solution. Experiments can be carried out to
illustrate the differences between strong, weak
and non-electrolytes. Use a circuit similar to
