Chapter 20 Flashcards
(28 cards)
Section 1
Relationship Between Chemical Reactions and Electricity
Chemical reactions can create electricity (e.g., batteries).
Electricity can drive chemical reactions that wouldn’t happen otherwise (e.g., electrolysis of water).
What is electricity?
The flow of electrons.
Which chemical reactions are happening?
Reactions that involve electron transfer, like oxidation and reduction.
What is an electrochemical cell?
A system where chemical reactions produce electricity or electricity causes chemical changes.
What is an electrode?
Conductor for electrical contact with nonmetallic parts.
What is a half-cell?
Electrode and electrolyte (ion solution).
How are the two electrodes connected?
By a wire.
What separates the two electrolytes?
Porous barrier or salt bridge.
What does the salt bridge do?
Prevents mixing of metal atoms and ions from half-reactions.
How is an electrochemical cell represented?
Anode electrode | Anode Solution || Cathode solution | Cathode electrode.
What does the double line represent in the notation?
Salt bridge.
What are the main differences between Electrolytic cells and Galvanic cells.
- Galvanic cells make electricity, electrolytic cells need electricity.
- Galvanic cells have natural reactions, electrolytic cells need forced reactions.
- Galvanic cells create energy, electrolytic cells use energy.
- In Galvanic cells, electrons flow naturally. In electrolytic cells, they are pushed.
What is a Voltaic cell?
An electrochemical cell that converts chemical energy into electrical energy through spontaneous reactions.
What are the three most common types of dry cells with examples.
1- Zinc-Carbon Dry cell (Batteries used in flashlights)
2- Alkaline Batteries
(Batteries found in a portable compact disc player)
3- Mercury Batteries
(The tiny batteries found in hearing aids, calculators, and camera flashes)
What are fuel cells?
Voltaic cells with continuous supply of reactants and removal of products.
What is corrosion?
A galvanic process that can be prevented using cathodic protection.
What is electrical potential in a voltaic cell?
The driving force that pulls electrons from the anode to the cathode.
In what units is electric potential or voltage expressed?
Volts (V).
What is electric potential analogous to?
Gravitational potential.
What is electrode potential?
The difference in potential between an electrode and its solution.
How is the potential difference in a voltaic cell measured?
By using standard reduction potentials from a table.
What is an electrolytic cell?
An electrochemical cell that requires electrical energy to drive a redox reaction.
How Electrolytic cells work?
The battery reverses the reaction by connecting positive to cathode and negative to anode.
What is electroplating?
Electrolytic process where metal ions are reduced and deposited on a surface.
