c6- electrolysis Flashcards
what is electrolysis?
the breaking down of a substance using electricity
what are positive ions known as?
cations
where do cations move to?
the cathode
what are negative ions known as?
anion
where do anions move to?
the anode
why can molten ionic compounds be electrolysed?
the ions can move freely and carry energy
in aqueous solutions, there will always be __________ from the water
hydrogen and hydroxide ions
in aqueous solutions at the cathode, what is produced if metal ions are more reactive than hydrogen?
hydrogen
in aqueous solutions at the cathode, what is produced if the metal is less reactive that hydrogen?
a solid layer of metal
in aqueous solutions at the anode, what is formed if OH- and halide ions are present?
molecules of chlorine bromine or iodine
in aqueous solutions at the anode, what is formed if no halide ions are present?
oxygen
in molten ionic compounds, what are positive metal ions reduced to?
metal atoms at the cathode
in a molten ionic compound, what are negative ions oxidised to?
atoms or molecules at the anode
what is a half equation?
they show how electrons are transferred during reactions, they show what happens at each electrode
what is an electrochemical cell?
a circuit with electrodes and electrolyte a power source and wires
