AP Chem Electrochemistry Galvanic Cells
36 flashcards covering AP Chem Electrochemistry Galvanic Cells for the AP-CHEMISTRY Unit 9 section.
Electrochemistry, specifically the study of galvanic cells, is a crucial topic in the AP Chemistry curriculum as outlined by the College Board. This area focuses on the conversion of chemical energy into electrical energy through spontaneous redox reactions. Understanding the components and functioning of galvanic cells, including electrodes, electrolytes, and cell potential, is essential for mastering this unit.
On practice exams and competency assessments, questions about galvanic cells often involve calculations related to cell potential, stoichiometry of redox reactions, and the identification of anodes and cathodes. Common traps include confusing the flow of electrons and the direction of ion movement, which can lead to incorrect answers. Additionally, students may overlook the importance of standard conditions when calculating cell potentials, which can skew their results. Remembering that galvanic cells are designed to operate under standard conditions can help clarify many of these concepts.
Terms (36)
- 01
What is a galvanic cell?
A galvanic cell is an electrochemical cell that converts chemical energy into electrical energy through spontaneous redox reactions. It consists of two half-cells connected by a salt bridge or porous membrane (College Board CED).
- 02
What are the components of a galvanic cell?
A galvanic cell consists of two electrodes (anode and cathode), an electrolyte solution, and a salt bridge or porous membrane to maintain electrical neutrality (College Board CED).
- 03
What is the function of the anode in a galvanic cell?
The anode is the electrode where oxidation occurs, releasing electrons that flow through the external circuit to the cathode (College Board CED).
- 04
What is the function of the cathode in a galvanic cell?
The cathode is the electrode where reduction occurs, gaining electrons from the external circuit (College Board CED).
- 05
How is the cell potential of a galvanic cell calculated?
The cell potential (E°) of a galvanic cell is calculated using the standard reduction potentials of the half-reactions: E°cell = E°cathode - E°anode (College Board CED).
- 06
What is the standard cell potential for a galvanic cell?
The standard cell potential is the voltage measured under standard conditions (1 M concentration, 1 atm pressure, 25°C) when the cell operates (College Board CED).
- 07
What happens at the anode during the operation of a galvanic cell?
At the anode, oxidation occurs, causing the release of electrons and the formation of cations in the electrolyte solution (College Board CED).
- 08
What happens at the cathode during the operation of a galvanic cell?
At the cathode, reduction occurs, where cations from the electrolyte gain electrons and are converted into neutral atoms or molecules (College Board CED).
- 09
What is the role of the salt bridge in a galvanic cell?
The salt bridge maintains electrical neutrality by allowing the flow of ions between the two half-cells, preventing charge buildup (College Board CED).
- 10
How does the concentration of reactants affect the cell potential of a galvanic cell?
According to the Nernst equation, the cell potential varies with the concentration of reactants and products; higher concentrations of reactants increase the cell potential (College Board CED).
- 11
What is the Nernst equation?
The Nernst equation relates the cell potential to the concentrations of the reactants and products: E = E° - (RT/nF)ln(Q), where Q is the reaction quotient (College Board CED).
- 12
What is the significance of the standard reduction potential?
The standard reduction potential indicates the tendency of a species to gain electrons; higher values suggest greater oxidizing power (College Board CED).
- 13
What is the relationship between Gibbs free energy and cell potential?
The relationship is given by the equation ΔG = -nFE°; a positive cell potential corresponds to a negative Gibbs free energy change, indicating spontaneity (College Board CED).
- 14
What occurs during the electrolysis of water in a galvanic cell?
During electrolysis, water is split into hydrogen and oxygen gases, with hydrogen forming at the cathode and oxygen at the anode (College Board CED).
- 15
What is a half-cell reaction?
A half-cell reaction is either the oxidation or reduction process that occurs at the anode or cathode in a galvanic cell (College Board CED).
- 16
What is the purpose of using a porous barrier in a galvanic cell?
A porous barrier allows ions to pass between half-cells while preventing the mixing of different solutions, maintaining separation of reactants (College Board CED).
- 17
How is the overall cell reaction determined in a galvanic cell?
The overall cell reaction is determined by combining the two half-reactions, ensuring that the number of electrons lost in oxidation equals the number gained in reduction (College Board CED).
- 18
What is the effect of temperature on the cell potential of a galvanic cell?
Temperature affects the kinetic energy of particles and can change the cell potential; typically, an increase in temperature increases the reaction rates (College Board CED).
- 19
What is the role of electrons in a galvanic cell?
Electrons flow from the anode to the cathode through the external circuit, providing the electrical energy generated by the redox reaction (College Board CED).
- 20
What is the significance of the electrode potential?
The electrode potential indicates how easily a species can be reduced or oxidized, influencing the overall cell potential of the galvanic cell (College Board CED).
- 21
What is the purpose of a voltmeter in a galvanic cell setup?
A voltmeter measures the cell potential, providing information on the voltage produced by the galvanic cell during operation (College Board CED).
- 22
How do concentration cells differ from standard galvanic cells?
Concentration cells consist of two half-cells with the same electrodes but different concentrations of electrolyte, generating a potential difference due to concentration gradients (College Board CED).
- 23
What is the relationship between the number of electrons transferred and the cell potential?
The number of electrons transferred (n) in the balanced cell reaction directly influences the cell potential, as seen in the Nernst equation (College Board CED).
- 24
What is the function of an external circuit in a galvanic cell?
The external circuit provides a pathway for electrons to flow from the anode to the cathode, allowing the conversion of chemical energy to electrical energy (College Board CED).
- 25
What are common applications of galvanic cells?
Galvanic cells are commonly used in batteries, electroplating, and corrosion prevention (College Board CED).
- 26
What is the impact of electrode surface area on a galvanic cell?
Increasing the electrode surface area enhances the reaction rate, potentially increasing the cell potential and overall efficiency (College Board CED).
- 27
What is the purpose of a reference electrode in electrochemistry?
A reference electrode provides a stable and known electrode potential against which other electrodes can be measured (College Board CED).
- 28
What is the effect of pH on the cell potential of a galvanic cell?
Changes in pH can alter the concentrations of hydrogen ions, affecting the cell potential according to the Nernst equation (College Board CED).
- 29
What is a Daniell cell?
A Daniell cell is a type of galvanic cell that consists of a zinc anode and a copper cathode, utilizing the redox reaction between zinc and copper ions (College Board CED).
- 30
What occurs during the corrosion of metals in galvanic cells?
Corrosion is an electrochemical process where metals oxidize, often facilitated by galvanic cells formed in the presence of electrolytes (College Board CED).
- 31
What is the purpose of a potentiometer in measuring cell potential?
A potentiometer measures the voltage of a galvanic cell without drawing current, providing an accurate potential reading (College Board CED).
- 32
What is the significance of the electrochemical series?
The electrochemical series ranks elements based on their standard reduction potentials, helping predict the direction of redox reactions in galvanic cells (College Board CED).
- 33
What is the role of ions in the electrolyte of a galvanic cell?
Ions in the electrolyte allow for charge balance and facilitate the movement of electrons between the anode and cathode (College Board CED).
- 34
How does the design of a galvanic cell impact its efficiency?
The design, including electrode materials and electrolyte concentration, affects reaction rates and overall efficiency of the galvanic cell (College Board CED).
- 35
What is the purpose of using inert electrodes in some galvanic cells?
Inert electrodes, like platinum, are used when the redox reaction does not involve the electrode material, ensuring no interference with the reaction (College Board CED).
- 36
How does the presence of a catalyst affect a galvanic cell?
A catalyst can speed up the rate of the redox reactions in a galvanic cell, potentially increasing the current output without affecting the cell potential (College Board CED).