Unit 5- Inorganic Chemistry- Principles and applications of
science II (examined unit)
A definition of an acid is a substance that releases hydrogen ions, a hydrogen iron is a proton.
Bases is something that can take up H+, usually to make water.
Acid + base = salt + water
An alkali is a base that can dissolve in water.
Alkalis often have a hydroxide ion, OH
Common Acids
Hydrochloric acid (Hcl)
Nitric acid (HNO3)
Sulfuric acid (H2SO4)
Phosphoric acid (H3PO4)
Ethanoic acid (Ch3COOH)
Common vases and alkalis
Sodium hydroxide
Potassium hydroxide
Ammonium hydroxide
Sodium hydrocarbonate (bicarbonate of soda, in baking powder)
PH scale
pH = -log [h+]
‘Strong’ in this context means highly ionised
Weak means not much ionised
Hcl H+ + cl-
, Uses of aluminium
Aluminium is used for power cables for light as they are lightweight and transmit high voltage over
long distance wires.
Aluminium is used for cans as aluminium cans are more malleable and lighter than steel and also
does not rust or corrode.
Aluminium Mining
- Aluminium ore is called Bauxite
- Bauxite is a red mineral made of aluminium oxide and iron oxides
- Bauxite is mined in various places, E.g. Russia, Jamaica
Bauxite Purification
- Bauxite is heated with sodium hydroxide
- The dissolves the alumina but not the other minerals
- The residue is filtered off acid disposed of.
- The filtrate is acidified and heated to produce pure alumina, aluminium oxide powder
Bauxite is a red/brownish colour (Can also be white/ tanned or tanned-yellow). It looks like
clay/soil. Bauxite is a mixture of aluminium oxide, iron oxide, and titanium dioxide.
The Bayer process: How alumina is produced from bauxite-
The Bayer process is carried out in four steps. First, after the bauxite is crushed, washed and
dried, it is dissolved with caustic soda at high temperatures. Next, the mixture is filtered to
remove the impurities, called “red mud,” which is properly discarded. The remaining
alumina solution is transferred to tall tanks called precipitators. In the precipitator tank, the
hot solution starts to cool and aluminium hydroxide seeds, very small particles, are added.
The aluminium hydroxide seeds stimulate the precipitation of solid aluminium hydroxide
crystals. The aluminium hydroxide settles at the bottom of the tank and is removed. Finally,
the aluminium hydroxide is washed of any remaining caustic soda and heated to remove
excess water. After this process, alumina (aluminium oxide) emerges as a fine white powder.
It looks much like sugar used in baking but is hard enough to scratch a pane of glass.
Extracting aluminium
- Aluminium is more reactive than carbon
- So carbon will not reduce aluminium oxide
- Aluminium cannot be extracted in a blast furnace
science II (examined unit)
A definition of an acid is a substance that releases hydrogen ions, a hydrogen iron is a proton.
Bases is something that can take up H+, usually to make water.
Acid + base = salt + water
An alkali is a base that can dissolve in water.
Alkalis often have a hydroxide ion, OH
Common Acids
Hydrochloric acid (Hcl)
Nitric acid (HNO3)
Sulfuric acid (H2SO4)
Phosphoric acid (H3PO4)
Ethanoic acid (Ch3COOH)
Common vases and alkalis
Sodium hydroxide
Potassium hydroxide
Ammonium hydroxide
Sodium hydrocarbonate (bicarbonate of soda, in baking powder)
PH scale
pH = -log [h+]
‘Strong’ in this context means highly ionised
Weak means not much ionised
Hcl H+ + cl-
, Uses of aluminium
Aluminium is used for power cables for light as they are lightweight and transmit high voltage over
long distance wires.
Aluminium is used for cans as aluminium cans are more malleable and lighter than steel and also
does not rust or corrode.
Aluminium Mining
- Aluminium ore is called Bauxite
- Bauxite is a red mineral made of aluminium oxide and iron oxides
- Bauxite is mined in various places, E.g. Russia, Jamaica
Bauxite Purification
- Bauxite is heated with sodium hydroxide
- The dissolves the alumina but not the other minerals
- The residue is filtered off acid disposed of.
- The filtrate is acidified and heated to produce pure alumina, aluminium oxide powder
Bauxite is a red/brownish colour (Can also be white/ tanned or tanned-yellow). It looks like
clay/soil. Bauxite is a mixture of aluminium oxide, iron oxide, and titanium dioxide.
The Bayer process: How alumina is produced from bauxite-
The Bayer process is carried out in four steps. First, after the bauxite is crushed, washed and
dried, it is dissolved with caustic soda at high temperatures. Next, the mixture is filtered to
remove the impurities, called “red mud,” which is properly discarded. The remaining
alumina solution is transferred to tall tanks called precipitators. In the precipitator tank, the
hot solution starts to cool and aluminium hydroxide seeds, very small particles, are added.
The aluminium hydroxide seeds stimulate the precipitation of solid aluminium hydroxide
crystals. The aluminium hydroxide settles at the bottom of the tank and is removed. Finally,
the aluminium hydroxide is washed of any remaining caustic soda and heated to remove
excess water. After this process, alumina (aluminium oxide) emerges as a fine white powder.
It looks much like sugar used in baking but is hard enough to scratch a pane of glass.
Extracting aluminium
- Aluminium is more reactive than carbon
- So carbon will not reduce aluminium oxide
- Aluminium cannot be extracted in a blast furnace
