C4 Knowledge organiser Flashcards
Atom
Smallest possible piece of an element. Has a radius of 0.1nm
Ion
A charged particle which can be positive or negative
Electron
A negatively charged particle found in energy levels around the nucleus. Has a relative mass of 0
Ionic Bonding
Occurs between a metal and non-metal element where the metal atom lodes electrons to a non-metal atom to form ions
Chemical Formula
Tells you which atoms and how many of them are present
Oxidation
A reaction where oxygen is added
Reduction
A reaction where oxygen is removed
Reactivity series
A table of elements in order of reactivity
Displacement
where a more reactive element displaces a less reactive element from its compound
Ore
An ore is a rock that contains enough of a metal compound in it to be worth extracting
Native metal
an unreactive metal that is found on its own in the ground
How can metals be placed in order of their reactivity
Add the metals to water or acid and see which ones react the most vigorously
Why is Platinum found in the Earth’s crust as the metal itself
It is unreactive
How are metals less reactive than carbon extracted from their ore
Reduction with carbon
Define oxidation in terms of electrons
Oxidation is the loss of electrons
Define reduction in terms of electrons
Reduction is the gain of electrons
State 3 common acids and give their formulae
HCL hydrochloric
Sulphuric h2so4
Nitric HNO3
Define an acid in terms of ions
An acid releases H+ ions in solution
How do you measure pH
With an indicator or a pH meter
what is a base
A metal oxide, hydroxide or carbonate that will react with an acid
Acids
A substance that has a pH less than 7
Alkalis
A soluble base that has a pH higher than 7
Neutral solution
A solution that has a pH of exactly 7
A salt
A salt is a compound where the hydrogen from an acid has been replaced with a metal
Neutralization
The reaction between an acid and a base to form a salt plus water
Electrolysis
A separation technique in which a compound is split into its elements using electricity
Anode
The positive electrode, made from carbon
Cathode
The negative electrode, made from carbon
Electrolyte
The substance that is getting split by electricity. Has to be either molten or an aqueous solution
Cryolite
A substance added to a aluminium oxide to lower its melting point
Cation
A positive ion that is attracted to the cathode in electrolysis
Anion
A negative ion that is attracted to the anode in electrolysis
Which ions are always present in a solution of an alkali
Hydroxide ions OH-
What types of salts are formed by the main 3 acids
HYdrochloric = Chlorides Sulphuric = Sulphates Nitric = Nitrates
Which ions always react in a neutralisation reaction
H+ and OH-
How does pH depend on the concentration of H+ in a solution
As the concentration of H+ increases by a factor of ten, the pH decreases by one
What are the main disadvantages of using electrolysis to extract metals
Required a large amount of energy to melt the compounds and to produce electricity
Why is aluminium oxide mixed with cryolite
To lower the melting point
In the electrolysis of an ionic solution, when will oxygen be produces
If the metal is not a halogen
What happens to water molecules in the electrolysis of solutions
They break up into hydrogen and hydroxide ions
