Electrolysis Flashcards
An electric current is
A flow of electrons or ions
Covalent compounds - conduct electricity?
NO- because the electrons are shared so are fixed in a certain position and are not able to move freely and conduct electricity.
Ionic compounds - conduct electricity?
NOT when solid because the ions aren’t free to move
YES when molten or in solution because the ions can move freely
Electrolysis is
A chemical change caused by passing on electric current through a compound that is either molten or in solution
An Electrolyte is
A substance that undergoes electrolysis. Covalent compounds AREN’T because they don’t contain ions
Anode
Positive electrode
Cathode
Negative electrode
PANC
Positive Anode Negative Cathode
Charges of common positive ions (cations) - 1+
H+ Na+ Ag+ K+ Li+ NH4+
Charges of common positive ions (cations) - 2+
Ba2+ Ca2+ Cu2+ Mg2+ Zn2+ Pb2+ Fe2+
Charges of common positive ions (cations) - 3+
Fe3+
Al3+
Testing for cations (Flame tests)
-Dip a platinum wire in Hydrochloric Acid and then into the solid, then into flame Li+ Red flame Na+ Strong orange flame K+ Lilac flame Ca2+ Brick red flame
Testing for cations (Precipitation reactions)
-Add sodium hydroxide solution to the solution containing:
NH4+, Ammonia = No precipitate is formed but there will be a strong smell and when heated will turn damp litmus blue -ALKALINE
Cu2+, Copper = Blue precipitate (Copper ll hydroxide)
Fe2+, Iron ll = Green precipitate (Iron ll hydroxide)
Fe3+, Iron lll = Orange- brown precipitate (Iron lll hydroxide)
Charges of common negative ions (anions) - 1-
Cl- Br- F- I- HCO3- OH- NO3-
Charges of common negative ions (anions) - 2-
O2-
S2-
SO42-
CO32-