TOPIC 11
Metals and their Properties
Metals and their Properties
Metals have distinctive properties such as:
1. Electrical Conductivity
2. Good Thermal Conductivity
3. Strength
4. Malleability.
Reactions of Metals
With Oxygen
All metals react with Oxygen. The more
reactive the metal the quicker the reaction.
In the lab the oxygen is produced by heating
potassium permanganate.
The brighter the glow the more the reactive the
metal. Less reactive metals produce a duller glow
General Equation
Metal + Oxygen
Metal Oxide
Metals + Oxygen (continued)
Potassium permanganate
acts as a source of
oxygen when Heated
The more active the metal the brighter
the glow
Mg metal is
placed
between two
pieces of
ceramic wool
Reactions of Metals
With Water
Only metals above hydrogen in the Activity
Series react with water.
In fact only the first three react with cold water.
The remaining metals above hydrogen must be treated
with steam before a reaction will take place.
General Equation
Metal + H2O
Metal Hydroxide + H2
Reactions of Metals
With Acids
Only Metals above Hydrogen in the Activity Series
react with Acids.
General Equation
Metal + Acid
Salt + Hydrogen
Metals and Acid (continued)
Pop
When a metal is reacted with
an acid it produces H2 gas
which burns with a POP!
Alloys
• An Alloy is a mixture of metals or metals
and other elements.
• Alloys are made to change the properties of
the metal e.g.to make them harder, more
pleasing on the eye or to make them more
resistant to corrosion.
• Examples are: brass (Cu + Zn), gold (Au + Cu)
( the greater the proportion of Cu the lower
the no.of carats), stainless steel (Fe, Ni and Cr)
Metal Ores
• Most metals are found combined with other
elements such as, oxygen and sulphur in the
earths crust. These are called Metal Ores.
• Only gold, silver and platinum are found
uncombined.
• As a result metals must be mined and then
separated from their ores by metal extraction
Extraction of Metals from their Ores
• Ores of metals high up in the electrochemical
series contain stronger bonds and therefore require
more sophisticated and expensive methods of
extraction
• Metals low down in the Electrochemical Series
form weak bonds with other elements. As a result
ores of these metals can broken up easily to obtain
the metal.
Electrochemical Series
Potassium
Sodium
Calcium
Magnesium
Aluminium
Zinc
Iron
Tin
Lead
HYDROGEN
Copper
Mercury
Silver
Gold
Platinum
Must be electrolysed to
release metal from ore
Separated from ore by heating
with CHARCOAL, thus releasing
CARBON DIOXIDE.
Can be broken by heat alone