Final answer:
The voltage of a galvanic cell is dependent on the materials involved, not the distance between electrodes. The distance affects resistance, not the voltage, which is determined by the substances' redox potentials and measured with a voltmeter.
Step-by-step explanation:
The voltage of a galvanic cell is influenced by the properties of the materials involved in the reactions at each electrode. However, the distance between the electrodes primarily impacts the resistance within the cell rather than the voltage itself. The potential energy difference between valence electrons of different substances determines the voltage generated by the cell. For example, the use of copper versus cobalt in combination with zinc will result in different voltages, 1.10 V and 0.51 V respectively, due to the different potential energy of their valence electrons.
While the placement of the electrodes can affect other factors, such as junction potential and the accuracy of voltage measurements, it does not directly change the cell's voltage, which is determined by the difference in electrical potential between the two half-reactions. This potential is measured by a voltmeter and is indicative of the energy needed to move charged particles within the electric field created by the reactions.
It is important to understand that increasing the distance between electrodes in a cell will primarily increase the resistance to the flow of charge. This might have an effect on the current and the rate at which reactions occur within the cell, but it does not change the inherent voltage which is a property dependent on the redox potentials of the substances involved in the electrochemical reaction.