What is an electric cell?
A device that converts chemical energy into electrical energy.
What is the purpose of an electric cell in a circuit?
To provide energy that drives the flow of electric current.
What are the main components of an electric cell?
Two electrodes (positive and negative) and an electrolyte.
What is an electrolyte?
A chemical substance that conducts electricity by allowing ions to move.
What happens at the electrodes in a working cell?
Chemical reactions occur that release or absorb electrons.
Which electrode is the anode in a cell?
The negative electrode, where oxidation occurs.
Which electrode is the cathode in a cell?
The positive electrode, where reduction occurs.
What is a simple cell?
A basic electric cell made with two different metals in an electrolyte.
Why do simple cells stop working after a while?
Because of polarization and depletion of reactants.
What is polarization in a simple cell?
The buildup of hydrogen gas at the cathode, which reduces current.
How can polarization be reduced?
By adding a depolarizer such as manganese dioxide.
What is a dry cell?
A type of electric cell where the electrolyte is in paste form.
What are common materials in a dry cell?
Zinc (anode), carbon rod (cathode), and a paste of ammonium chloride and manganese dioxide.
Why is zinc used as the anode in dry cells?
Because it is more reactive and gives up electrons easily.
What role does manganese dioxide play in a dry cell?
It acts as a depolarizer by reacting with hydrogen gas.
What are the advantages of dry cells?
They are portable, compact, and leak less than wet cells.
What is a battery?
Two or more electric cells connected together to provide higher voltage.
What is an electromotive force (EMF)?
The voltage generated by an electric cell or battery.
What affects the voltage of a cell?
The types of electrodes and the electrolyte used.
What is internal resistance in a cell?
The resistance to current flow within the cell, which reduces the output voltage.
What is a Voltaic cell?
A simple electric cell developed by Alessandro Volta using zinc and copper plates in dilute acid.
What is a major drawback of the Voltaic cell?
It suffers from polarization due to hydrogen gas buildup on the copper electrode.
Who developed the Daniell cell?
John Frederic Daniell.
What metals are used in the Daniell cell?
Zinc and copper.
What are the electrolytes in a Daniell cell?
Copper(II) sulfate for the copper electrode and zinc sulfate for the zinc electrode.
How is polarization avoided in the Daniell cell?
By using separate electrolytes and a porous pot or salt bridge.
What is the function of a salt bridge in a Daniell cell?
It maintains electrical neutrality by allowing ion flow between the half-cells.
What is the overall reaction in a Daniell cell?
Zn(s) + Cu²⁺(aq) → Zn²⁺(aq) + Cu(s)
What is a Leclanché cell?
A type of dry cell invented by Georges Leclanché, used in early batteries.
What are the components of a Leclanché cell?
Zinc anode, carbon cathode, and a paste of ammonium chloride and manganese dioxide as electrolyte.
What role does manganese dioxide play in the Leclanché cell?
It serves as a depolarizer by reacting with hydrogen gas at the cathode.
Is the Leclanché cell rechargeable?
No, it is a primary (non-rechargeable) cell.
What is a lead-acid accumulator?
A secondary (rechargeable) battery using lead and lead dioxide electrodes in sulfuric acid.
What happens during the discharge of a lead-acid accumulator?
Both electrodes are converted to lead sulfate, and electrical energy is produced.
What happens during the charging of a lead-acid accumulator?
The chemical reactions are reversed, converting lead sulfate back to lead and lead dioxide.
Why is sulfuric acid important in a lead-acid accumulator?
It acts as the electrolyte and takes part in the redox reactions.
What is the EMF of a typical lead-acid cell?
About 2 volts per cell.
Why are lead-acid batteries used in vehicles?
They provide high current for starting engines and are rechargeable.
How can you tell if a lead-acid battery is discharging?
The specific gravity of the electrolyte decreases.
How is a lead-acid accumulator maintained?
By keeping the electrolyte level above the plates and charging it properly.
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