C5 Electricity and Chemistry Flashcards
Compare the movement of electrons to the movement of ions in electrolysis
Electons move through wire from positive electrode ro negative while Ions move through the electrolyte. Positive ions>negative electrode
Negative ions>positive electrode
During the extraction of aluminium, why is aluminium oxide dissolved in molten cryolite?
Bc Al has a v high melting point. Dissolving it in molten cryolite decreased its melting point reducing costs and energy
Why are copper and steel-cored aluminium used in cables?
They both are good conductors of electricity
Copper:electrical wirin
Al: overhead wires
What forms at each electrolyte during the electrolysis of dilute sulfuric acid?
Anode:oxygen
Cathode: hydrogen
What forms at each electrode during the electrolysis if concentrated sodium chloride solution
Anode: Chlorine
Cathode:Hydrogen
What forms at each electrode during the electrolysis of concentrated hydroclohyric acid
Anode: chlorine
Cathode: hydrogen
What forms at each elecrode during the electrolysis of molten lead bromide
Cathode: lead
Anode: bromine
How can you predict whether a metal or hydrogen will form at the cathode during electrolysis of an aqueous compound?
If hydrogen is above the metal in the reactivity series, then the metal will form. If the metal is above hydrogen, then hydrogen will form
What is formed at each electrode in electrolysis
Anode: non metal
Cathode: hydrogen or metal
Products of electrolysis of dilute zinc chloride solution
Anode: Oxygen
Cathode: zinc
Products if electrolysis of concentrated potassium bromide solution
Anode: bromine
Cathode: hydrogen
What happens at the cathode during electrolysis
Cations gain electrons to form their elements. known as REDUCTION
What is electroplating
A process in which a metal is coated with a layer of another metal
Predict the products of electrolysis of concentrated copper iodide solution
Anode: iodine
Cathode: copper
Electrolysis
The breakdown of molten or aqueous ionic compounds using electricity
Reasons for using electroplating
-to prevent corrosion
-to improve appearance
What forms at each electrode during the electrolysis of molten zinc chloride
Anode: chlorine
Cathode: zinc
How does electroplating work?
The metal being coated is the cathode. The metal that will form the exterior is the anode. The electrolyete solution must contain ions of the metal which will form the outer coating.
Why are plastics and ceramics used as insulators
They prevent the flow of electricity and dont conduct it
What is the cathode and anode
Cathode- negative electrode
Anode- postive electrode
What happens at the anode during electrolysis
The anions lose electrons to form their elements. This is oxidation
Where do the ions in the electrolyte move to during electrolysis
Cations move towards the cathode
Anions move towards the anode
Describe the electrolysis of copper sulfate solution using carbon electrodes
Copper ions gain electrons at the cathode to form pure copper. Oxygen ions lose electrons at the anode to form oxygen gas
How can the products od electrolysis of molten electrolytes be predicted
Anode: non metal
Cathode: metal element
What forms at each electrode during the electrolysis of copper sulfte solution using copper electrodes
Anode: copper ions
Cathode: copper
What forms at each electrode during the electrolysis of copper sulfate solution using inert electrodes
Anode: oxygen
Cathode: copper
Half equations for the electrolysis of aqueous NaCl
Cathode: 2H+ +2e->H2
Anode: 2Cl->Cl2+2e-
Molten lead bromide electrolysis half equations
Cathode: Pb2+ + 2e- > Pb
Anode:2Br- > Br2+ 2e-
