Lecture 6 Flashcards
What is a electrolyte?
The electrolyte is the compound that is decomposed; it is either molten ionic compound or a concentrated aqueous solution of ions.
What is electrolysis?
Electrolysis is the decomposition of a compound into its elements by an electric current.
What are the uses of electrolysis?
Used to extract metals that are high in the reactivity series. Used to produce non-metals such as chlorine and to purify some metals.
What are electrodes?
Electrodes are rods, made from either carbon or metal. which can conduct electricity to and from the electrolyte. The anode is positive and the cathode is negative.
What power supply should electrolysis use\?
Direct current
What forms at the cathode?
Either a metal or hydrogen forms. If a metal is more reactive than hydrogen, its ions stay in solution and hydrogen bubbles off. But if the metal is less reactive than hydrogen the metal forms.
What is the order of most reactive metals to least reactive
Potassium
Sodium
Calcium
Magnesium
Aluminium
Zinc
Iron
Lead
Hydrogen
Copper
Silver
What is the anode?
A non-metal other than hydrogen forms. If it is a concentrated solution of a halide the chlorine, bromine, iodine forms.
If KBr solution is used what material should the cathode and anode be?
Cathode=hydrogen Anode=Bromine
If AgNO3 solution is used what material should the cathode and anode be?
C=silver A=oxygen
If HCl solution is used what material should the cathode and anode be?
C=hydrogen A=chlorine
If NaCl solution is used what material should the cathode and anode be?
C=hydrogen A=chlorine
Why is zinc used as a anode?
Because the alloy is less resistant to the saltwater’s electrolytes.
What is brine?
Brine is a concentrated solution of sodium chloride.
What is the symbol reaction of brine?
2NaCl + 2H2O = 2NaOH +Cl2 +H2
Uses for Chlorine?
Plastic PVC, Medical drugs, paints and bleaches
Uses for sodium hydroxide solution?
Soaps, detergents, paper and dyes.
Uses of hydrogen?
Making nylon, make hydrogen peroxide and as a fuel in hydrogen fuel cells.
What is electroplating?
Electroplating means using electricity to coat one metal with another, to make it look better or to prevent corrosion.
Examples of electroplating
Steel car bumpers are coated with chromium. Steel cans are coated with tin to make tins for food.
If you want to purify a metal by electrolysis, will you make it the anode or the cathode?
The cathode because the anode is made of impure metal and the cathode is made of pure copper. The anode dissolves to form metal ions.
What is a salt bridge?
electrical neutrality within the internal circuit.
preventing the cell from taking its reaction to equilibrium.
Not used the reaction will likely continue
What is an electrolytic cell?
An electrolytic cell is a type of electrochemical cell in which non-spontaneous redox reactions convert the electric energy to chemical energy.
The anode is the positive electrode and the cathode is the negative electrode.
What is a electrochemical cell?
An electrochemical is a cell in which non-spontaneous redox reactions convert chemical energy into electrical energy or vice versa.
The cathode is the positive electrode and the anode is the negative electrode.
What happens if the external potential applied is greater than the E cell of an electrochemical cell?
If the external potential applied is greater than the E cell of an electrochemical cell then the electrochemical cell behaves like an electrolytic cell. All the chemical reactions will be flipped and the electrical energy will be transformed into the chemical energy.
What is a galvanic cell?
A galvanic cell is a cell in which spontaneous redox reactions convert chemical energy to electric energy.
In it, electric energy is generated by redox reactions.
What is a primary cell?
A primary cell is a cell that is designed to be used once and discarded. In general, the electrochemical reaction occurring in the cell is not reversible, and so these cells cannot be recharged.
Examples of these Cells are dry Cells, Daniel Cells, etc.
