Chemistry A1 (complete) Flashcards
Acid
a substance that dissociates in water to form positive hydrogen ions
Base
a substance that will react with acids to form salt and water
Alkali
a base that dissolves in water to form negative hydroxide ions
Amphoteric
substances that can act as both an acid and a base
Why is Aluminium useful
it is chemically inert (unreactive) except in hot acids/bases and amphoteric
uses of Aluminium
drying agent
paint
sun cream
filer
glass
Salt
formed when the cation in an acid is replaced by a different cation often a metal or ammonium
Metal oxides
bases
Metal hydroxides
Alkalis
electrolysis
the decomposition of a compound using electricity
effluent
liquid waste usually discharged into a river or stream
acid + metal hydroxide =
salt + water
Activation energy
minimum amount of energy needed between colliding particles in order for a successful collisions to take place
contact process
industrial production of sulfuric acid
steps of the contact process
- sulfur is burnt in oxygen to produce sulphur dioxide (S + O2 -> SO2)
- sulphur dioxide takes part in a reverse reaction with more oxygen to make sulphur trioxide. Vanadium oxide is added as the catalyst for sulfur dioxide to react with forming V2O4. it then regrates to V2O5
- a small amount of sulfuric acid is used with the sulfuric trioxide to make fuming sulfuric acid
- water is added to produce sulfuric acid
Iron in the harbour process
provides a surface area for hydrogen and nitrogen to absorb/bind to. this weakens the reactants allowing the chemical reaction to take place more easily therefore lowering the reaction activity.
discribe titaniums ore
titaniums ore is called rutile and consists of itanium oxide
why cant carbon be used as reducing agent in the production of pure titanium
because it would make the titanium britle
what is used as a reducing agent in the production of titanium
magnisium
why is pure titanium expensive
because only a small amout is made at one time
what is a batch process
a process that takes place in two stages
steps of the Kroll process
Stage one: titanium oxide is converted into titanium chloride using chlorine and carbon
Stage two: titanium chloride is reduced using magnisium
what envirement is the redcution of titanium carried out in
it is carried out in an argon atmosphere to prevent the titanium reacting with water or oxygen
what is brine
aqueous sodium chloride
what is produced from brine electrolysis and what is it used for
- chlorine gas which can be used in cleaning products
- hydrogen gas which can be used as feul
- sodium hydroxide solution which can be used in bleach and other cleaning products
what are the two cell types that can be used in the electrolysis of brine
diaphram and membrane
what is product at the anode
the electrolysis of brine
chlorine gas
2Cl- 🡢 Cl^2 +2e-
What is produced at the cathode
the electrolysis of brine
hydrogen gas
2H+ + 2e- 🡢 H^2
explain the key fetures of the diaphagm cell model
the electrolysis of brine
- brine is pumped in on a higher level to ensure the flow is from left to right and to prevent the back flow of sodium hydroxide
- some brine will be left over in the sodium hydroxide produced
explain the key fetures of the membrane cell
the electrolysis of brine
- it only allows the movement of postive ions across the ion exchange membrane, this means brine does not cross it. This results in purer sodium hydroxide
Bauxite
Aluminium ore
Slurry
semi-liquid material containing fine soild particals
Flocculants
substances that cause particles to clump together
Calcination
using heat to remove water
the steps of extracting alumina from bauxite
- large pieces of bauxite are crushed up into small grains
- hot sodium hydroxide is added to the small grains to dissolve the aluminium minerals. this is known as digestion and produces slurry
- the slurry us taken and filtered to remove large residue leaving alminium compound
- the alminium comound is left to cool, forming crystals. flocculants are added to aid the sedimentation process. the sodium hydroxide is recovered and reused
- calcination is carried out on the crystals leaving alumina
the steps to create aluminium from alumina
- alumina is dissolved in cryolite
- electolysis is used to produce molton aluminum
what is used as the electrolyte in the elctrolysis of alumina
molten cryolite is used because it melts at -1000 and the alumina easly dissolves in it.
To further reduce the melting point aluminium fluoride it added.
What happens to the water present in the electrolysis of brine
The water molecules dissociate
why is aluminium usefull and what is it used for
aluminium is versatile, its lightweight, unreactive and flexable making it uses full for many things.
* cans, foils, kitchen utensils, window frames, beer kegs and aeroplane parts
Properties of titanium
Reactive
Non-corrosive
High strength to weight ratio
Uses of titanium
Aerospace- air craft engines
Golf cubs
