Electrochemistry
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What is an oxidizing agent
The compound which gains electrons (undergoes reduction)
What is a reducing agent
A compound which loses electrons (undergoes oxidation)
Where does reduction occur
Reductions always occurs at the cathode
Where does oxidation occur
Oxidation always occurs at the anode
What are the functions of a salt bridge?
• It maintains electrical neutrality within the half cells • It completes the circuit, it connects both half cells together.
What is an electrolyte ?
An electrolyte is a solution that contains free ions and therefore behaves as a conductor of electricity
What is a galvanic cell?
A electrochemical cell which converts chemical energy into potential energy
How do electrons flow ?
From the anode to the cathode
What is a spontaneous reaction?
A reaction that occurs without the need for an external power supply
What is a non spontaneous reaction
A reaction that needs an external power source (a battery) to take place
What is electrolysis ?
The process of converting electrical energy into chemical energy by passing an electrical current through an ionic solution
Where does electrolysis occur ?
Electrolysis occurs in electrolytic cells
What is an electrolytic cell ?
An electrochemical cell that converts electrical potential energy to chemical energy to drive a non spontaneous reaction
What is a half cell
A structure that consists of a conductive electrode surrounded by electrolytes
Describe the flow of electrons
Electrons flow from an area of high concerns to an area of low concentration
How does the E⁰ cell values affect the flow of current?
The larger the difference between the excess and deficit of electrons, the faster the electrons will flow and the greater the current will be.
How does the E⁰cell value affect the rate of reaction?
The faster the electrons flow, the greater the reaction will be.
How is the rate of reaction affected when the current applied is increased?
The rate of reaction also increases.
If the E⁰ cell value is positive then?
The reaction is spontaneous Therefore the oxidising agent had a higher electron affinity The reduction agent has a higher tendency to lose electrons
If the E⁰ cell value is negative then?
The reaction is non spontaneous The one being oxidised, the reducing agent has a higher electron affinity than the one being reduced.
What does the magnitude of the E⁰ cell value indicate ?
A large E⁰ cell value suggests a stronger tendency for the forward reaction to occur A small value indicates a weaker tendency to occur spontaneously
What does the E⁰ value of a substance tell us?
A high value tells us that the substance gets reduced more easily A low value tells us that it oxidises more easily (Electrons don’t want you if you’re already negative, that are attracted to positive charge)
Standard conditions of an electrochemical cell
Concentration : I mol.dm³ Pressure : 1 ATM Temperature: 25⁰C / 298K
What is emf ?
Electromotive force is the maximum potential difference between 2 electrodes or half cells