C3.4 Flashcards
electrolysis
the process in which an electric current is passed through an electrolyte, causing an ionic compound to split apart into its elements
what is the acronym for the electrodes used in electrolysis?
Positive
Anode
Negative
Is
Cathode
what are the acronyms used for reduction and oxidation at the electrodes?
“Red Cat”
“An Ox”
what must an electrolyte contain?
must contain free moving ions
what are electrodes made of?
they are inert and often made of graphite
can water be ionic?
yes
what are the two ions in water?
H+ ions and OH- ions
what ions are present in aqueous solutions?
H+ ions, OH- ions and the ions from the ionic compound
discharged
the ions lose their charge
electroplating
when one metal is covered with another metal using electrolysis with non-inert electrodes
non-inert
reactive
what are the basics of electrolysis?
-when an ionic compound is molten, the ionic bonds are broken, leaving the positive ions and negative ions free to move
-when the electricity is passed through the electrolyte the ions are attracted to oppositely charged electrodes
-at the electrodes oxidation and reduction occurring turning the ions into atoms or molecules
only one ion can be discharged at each electrode- so how do you choose which one discharges?
-hydrogen normally forms at the cathode but a less reactive metal (copper or silver) will form if available
-oxygen (forms from hydroxide ions) normally forms at the anode but if the ions are in group 7 they will form instead
electroplating basics
-cathode is the object you want to plate
-anode is the metal you would like the object to be plated in
-the electrolyte contains ions of the metal you are plating with
how do you purify copper using electroplating?
-anode is impure copper
-cathode is pure copper
-electrolyte contains copper ions
-cathode gains copper atoms and increases in mass, reduction
occurs
-anode loses copper atoms and decreases in mass, oxidation occurs
-impurities from the anode fall off and collect underneath it
