Chemistry MTA Unit 2 Flashcards
What is an ore?
An ore is a when a metal is contained in rock
What is oxygen in terms of electrons?
Loss
What is reduction in terms of electrons?
Gain
What is oxygen in terms of oxidation?
Gain
What is reduction in terms of oxygen?
Loss
Give examples of metals extracted by electrolysis
Potassium (K) Sodium (Na) Calcium (Ca) Magnesium (Mg) Aluminium (Al)
Why don’t aluminium cans react with their contents?
Because when exposed to oxygen a chemical reaction occurs forming a protective layer of aluminium oxide which prevents any further reaction between the metal and oxygen
What is the density of an aluminium can like?
Low
What happens to aluminium in electrolysis
Cryolite is added to power the melting point of the rock as it’s cheaper than heating aluminium up all the way bc it has a high melting point. The aluminium will be attracted to the negative cathode (as all metals-pos so attracted to neg) and the oxygen will be attracted to pos anode as it’s neg. At the cathode you need to re add electrons to turn it into pure aluminium atoms
Define electrolysis
When electricity is used to separate ionic compounds
What’s an ion?
When atoms become charged (I.e when a metal atom loses electrons to form a positively charged ion and the non metal gains the electrons to become negatively charged)
Why do substances have to be molten during electrolysis?
So ions can move (it can be heated or dissolved to become molten)
What happens in electrolysis when you have an aqueous solution at the CATHODE
There will be hydrogen and hydroxide atoms from the water as well as the atom, so:
At the cathode (if H ions and metal ions are present) H gas will be produced IF the metal ions form an elemental metal MORE reactive than hydrogen.(ie from iron to potassium on periodic table)
If it’s LESS reactive then H then a solid layer of pure metal will be produced instead (I.e Copper, sliver or gold)
What happens to aqueous solutions at the ANODE
If hyrdoxide ions and halide (i.e chlorine, bromine or iodine) ions ARE present, molecules of chlorine, bromine or iodine will be formed
If NO halide ions are present, then the OH- (hydroxide) ions are discharged and oxygen gets formed
What does chlorine do to damp litmus paper?
Bleach it
