Chemistry: Chemical Changes Flashcards
what pH is an acid
0 - 6
what pH is a base
8 - 14
what pH is neutral
7
what is an alkaline
base that dissolves in water
what is the reaction between acids and bases called
neutralisation
what are titrations used for
find out concentrations
what do strong acids do in water
ionise completely in water and all acids particles dissociate to release H+ ions
what do weak acids do in water
do not fully ionise and only a small proportion of acid particles dissociate to release H+ ions
name the reactivity series in order of reactivity
Potassium K, Sodium Na, Lithium Li, Calcium Ca, Magnesium Mg, Carbon C, Zinc Zn, Iron Fe, Hydrogen H, Copper Cu
what is an oxidation reaction
gain of oxygen
what is a reduction reaction
loss of oxygen
what is a displacement reaction
more reactive metal will displace a less reactive metal from its compound
what is electrolysis
using electrical current to split up a compound into ions
where do positive ions in the electrolyte go
move towards the cathode (negative electrode) and gain electrons
where do negative ions in the electrolyte go
move towards the anode (positive electrode) and lose electrons
why are some solids made into molten for electrolysis
an ionic solid can’t be electrolysed because the ions are in fixed positions and can’t move
what are the two rules for what is collected at the electrodes during electrolysis in an aqueous solution
at the anode either OH- ions or a halide ion
at the cathode either H+ ions or a less reactive positive ion
