Galvanic Cells as a Source of Energy Flashcards
Describe an electrochemical cell
Device in which chemical energy is converted into electrical energy, or vice versa
Describe a galvanic cell
Electrochemical cell in which chemical energy is converted into electrical energy.
Provide an alternative term to describe a galvanic cell
Voltaic cell
State what a salt bridge is often made from
Filter paper soaked in a relatively unreactive electrolyte (e.g. potassium nitrate solution)
State an early form of the galvanic cell
Daniell Cell
Describe an electrolyte
A chemical substance that conducts electric current as a result of dissociation into positively and negatively charged ions, which migrate toward the negative and positive terminals of an electric circuit.
Describe an electrode
A solid conductor in a half-cell at which oxidation or reduction reactions occur.
Describe electrolysis
Process that produces a non-spontaneous redox reaction by the passage of electrical energy from a power supply through a conducting liquid.
State whether a metal displacement reaction in a Daniell Cell is spontaneous or non-spontaneous
Spontaneous
Describe half-cell
Half of an electrochemical cell.
State what the species present in each half cell forms
A conjugate redox pair
Describe a conjugate redox pair
Oxidising agent and the reducing agent that is formed when the oxidising agent gains electrons
State what half cells usually contain
Other species that are not involved in the reaction (e.g. spectator ions or a solvent)
State the term used to identify the electrode at which oxidation occurs
Anode
State the term used to identify the electrode at which reduction occurs
Cathode
State what terminal the anode of a galvanic cell is considered
Negative
State what terminal the cathode of a galvanic cell is considered
Positive
State the purpose of a salt bridge in a galvanic cell
Contains ions that are free to move so that they can balance charges formed in the two compartments
State to what terminal cations move towards
Cathode
State to what terminal anions move towards
Anode
State what would occur to the conditions within a galvanic cell if a salt bridge was not present
Solution in one compartment - accumulate negative charge
Solution in other compartment - accumulate positive charge
State an alternative term associated with the salt bridge
Internal circuit
State what affect the accumulation of charge in one or both compartments of the galvanic cell (in the absence of a salt bridge) would have on the reaction
Stop reaction and prevent further reaction
State what a metal displacement reaction is an example of
Spontaneous exothermic reaction
State what a metal displacement reaction could be identified as if the reactants are allowed to come into direct contact with one another
Spontaneous exothermic reaction - chemical energy is transformed directly to thermal energy
State whether a metal displacement reaction in a galvanic cell can be classified as a spontaneous exothermic reaction
No. The reactants do not come in contact with one another therefore a chemical-thermal energy transformation cannot occur. (Instead a chemical-electrical transformation occurs).
