AP Chemistry electrochemistry

What is electrochemistry?

The study of chemical processes that cause electrons to move, relating to electricity.

Define oxidation.

Loss of electrons from an atom, ion, or molecule; increases oxidation state.

Define reduction.

Gain of electrons by an atom, ion, or molecule; decreases oxidation state.

True or false: Anode is where oxidation occurs.

True, because oxidation happens at the anode in electrochemical cells.

True or false: Cathode is where reduction occurs.

True, because reduction occurs at the cathode in electrochemical cells.

Difference between galvanic and electrolytic cells.

Galvanic cells generate electricity from spontaneous reactions; electrolytic cells require external voltage to drive non-spontaneous reactions.

What is a salt bridge?

An electrolyte-filled tube that connects two half-cells in a galvanic cell, maintaining charge balance.

Fill in the blank: The standard electrode potential (E°) is measured in _____ volts.

Volts.

What does Nernst equation calculate?

It calculates the cell potential under non-standard conditions: $\displaystyle E = E° - \\frac{RT}{nF} \ln Q$.

Define standard hydrogen electrode (SHE).

A reference electrode with a potential of 0.00 V, used to measure other electrodes.

What are electrolytes?

Substances that dissociate in solution to produce ions, conducting electricity.

True or false: Electrode potential increases with the concentration of reactants.

True, because higher concentration of reactants increases the tendency to gain electrons.

What is Faraday's constant?

The charge of one mole of electrons, approximately $\displaystyle 96485 \text{ C/mol}$.

Difference between primary and secondary batteries.

Primary batteries are non-rechargeable; secondary batteries can be recharged and reused.

What is corrosion?

The gradual destruction of materials, often metals, due to electrochemical reactions.

What is a half-cell?

A single electrochemical reaction site where either oxidation or reduction occurs.

Fill in the blank: In a galvanic cell, the flow of electrons is from _____ to _____.

Anode to cathode.

What does the term 'cell potential' refer to?

The voltage difference between two electrodes in an electrochemical cell.

True or false: A higher E° means a stronger oxidizing agent.

True, because higher E° indicates a greater tendency to gain electrons.

What is the primary reaction in a lead-acid battery?

The reaction involves lead (Pb) and lead dioxide (PbO₂) in the presence of sulfuric acid (H₂SO₄).

Define electrolysis.

The process of using electrical energy to drive a non-spontaneous chemical reaction.

What is the role of a cathode in electrolysis?

It is the electrode where reduction occurs, gaining electrons from the electrolyte.

What does 'Q' represent in the Nernst equation?

The reaction quotient, which is the ratio of products to reactants at any point in the reaction.

What is the purpose of a voltmeter in an electrochemical cell?

To measure the cell potential, indicating the voltage difference between electrodes.

Fill in the blank: In an electrolytic cell, the cathode is _____ and the anode is _____.

Negative; positive.