electrochem Flashcards
half cells
compartments of a galvanic cell, including electrons
electrodes
conducting substance that electrons can enter or leave
anode
negative electrode
where oxidation takes place
source of electrons and is the negative terminal of the galvanic cell
cathode
postive electrode
where reduction takes place
receives electrons and is the positive terminal on the galvanic cell
electrolyte
ionic compound that conducts electricity when its dissolved in water
wire
connects the anode and the cathode together
lets the electrons flow from the ANODE to the CATHODE in an external circuit
salt bridge
prevents the build up of a POSITIVE CHARGE in the OXIDATION HALF REACTION
prevents the build up of a NEGATIVE CHARGE in the REDUCTION HALF REACTION
keeps each half cell neutral
voltmeter
measures the amount of electricity produced
chemical analysis
electrochemical analysis and redox reactions are used in chemical analysis
glucose sensors used by diabetics and breathalyzers are based on redox reactions
electroplating and metal purification
when corrosion resistant metal coating is applied to a metal object
done by making the metal object the cathode of an electrochemical cell,
electrochemical process ex 1
electrochemical processes are used to produce aluminum metal from its mineral ore AI2O3
electrochemical process ex 3
electricity is used in an electrochemical process called the chlor-akali process
produces hydrogen and chlorine gasses + hydroxide from chlorine and water
used to produce industrial and commercial products
batteries
can produce electricity from chemical reactions
electrical cells and batteries
batteries has 2 or more galvanic cells connected together to increase the amt of electricity produced
primary cells (dry cells)
disposable batteries
common types are
- zinc chloride
- alkaline dry cells used in flashlights, watches, kids toys
irreversible redox reaction, when that reactants are used up the battery cant produce electricity anymore
secondary cells
rechargeable batteries absed on reversible redox reactions
can be recharged by using an external source of electricity
recharges the battery by reversing the reaction
fuel cells
doesnt have a limited amount of reactants
similar to filling a gas tank
fuel cell reactants flows continuously into the cell from an external source
ways to prevent corrosion
avoid mechanical stress
coating, coating a metal with paint to prevent it from reacting w air
making metal alloy, adding another metal to metal alloy, adding chromium to the metal alloy formed steel forms stainless steel
galvanizing, coating a metal with a more reactive metal (eg coating metal with zinc)
ways to prevent corrosion c1
cathodic protection, turning a potential anode into a cathode
sacrificial anode- more reactive metal like zinc id attached to the surface of a diff metal like iron, iron becomes the cathode instead of anode
ways to prevent corrosion c2
impressed current- forcing current to a potential anode like iron so that it becomes a cathode
used to prevent corrosion of piplines
