1142 Questions & Blanks Flashcards
The three basic parts of a voltaic cell
cathode
anode
electrolyte
An electrode is a _____ that _________
solid
conducts an electric current
An electrolyte conducts electricity when it _______
is dissolved in water
How does an electrolyte conduct electrical charges?
The electrolyte forms ions and these ions conduct an electrical charge from the cathode to the anode.
In a copper-zinc voltaic cell:
cathode = zinc anode = copper electrolyte = sulfuric acid in water
What is a battery?
an arrangement of several voltaic cells connected in series or in parallel
What is the main advantage of connecting cells in parallel rather than in series?
larger current intensities
series
affect voltage
lower current
parallel
affect amperes
higher current
Electrochemical potential difference is
the difference between the electrochemical energy of a neutral atom compared to its electrochemical energy as an ion
How are physicists able to predict a battery’s cell voltage without actually measuring it with a voltmeter?
by comparing the electrochemical potential of the metals involved in the chemical reaction
Why would the combination of sodium and magnesium not make a useful voltaic cell?
they have a low difference of electrochemical potential
List the three weaknesses of the zinc-copper voltaic cell
cannot be recharged
corrosive electrolyte spills easily
expensive electricity
Electrolysis is
the separation of a molecule into its respective elements by passing an electric current through an electrolyte
an electrolytic cell is
two metal plates each connected to a battery terminal and placed in an electrolyte
Faraday’s first law of electrolysis
the mass of an element released at an electrode during electrolysis by a steady current is directly proportional to the quantity of electric current passing through the electrolyte
Valence
a measure of the combining power of atoms
Positive valence number
an atom has one or more electrons in its outer shell that is willing to give up or share with other atoms
Negative valence number
the number of valence electrons that an atom seeks to obtain from other atoms
atomic mass
the mass of an atom compared to the mass of a carbon-12 atom
Faraday’s second law of electrolysis
the mass of a substance liberated at the electrodes during electrolysis by a steady current is proportional to the equivalent mass of that substance
The functions of the armature, field magnet, and rings in an electric generator
the armature rotates between the poles of a field magnet, the field magnet induces current in the rotating armature, and the rings carry the current away from the armature to the circuit
Why does an electric generator normally produce alternating current?
Each time the armature passes the opposite pole of the field magnet, the magnetic field induces current in the opposite direction
What is a synchronous motor?
one whose speed is regulated at the frequency of an alternating current
