Lab report: electrical conductance
Lab report: electrical conductance
Introduction
Electrical conductance is the property of an electrical conductor that determines how fast it contacts – how easily current flows through it (Shaw, 1911, p. 281). When a potential difference is applied across various types of conductors, current flows through the conductors at different rates. The rate at which the current flows through a particular conductor for a particular potential difference is dependent on the specific property of the conductor, referred to as electrical conductance. Conductance determines how well current flows through a particular conductor. Conductance is the inverse (reciprocal) of the property of the conductor to resist current flow (resistance):
(1)
Current traveling along a conductor gets a difficult path to travel. Thus conductor is reduced. This means that conductance is inversely proportional to the length of the conductor.
. (2)
Increasing the cross-sectional area of the conductor increases the electron drift. Thus the conductance is increased. Conductance is proportional to cross-sectional area.
(3)
(4)
Where is proportionality constant called conductivity (specific conductance).
Procedure
Solvent measurement
The conductance of pure water was measured and subtracted from conductance for each remaining solutions.
(5)
Cell constant
0.7455 g off KCl was dissolved in deionized water and diluted to 1 l to prepare a 0.01N KCl solution. The solution was used to rinse the cell several times. The cell was filled with the solution and left for 10 minutes for the temperatures to equilibrate with the water bath. The temperature was taken. The procedure was repeated two times with fresh KCL and temperature measured each time.
strong electrolyte
A strong solution of O.1 N KCl was used to prepare KCl solutions with the following normalities: 0.02N, 0.015N, 0.01N, 0.0075N, 0.005N, 0.004N, and 0.002N using deionized water.
Results
Data sheet.
Weak Electrolyte
Strong Electrolyte
Discussion
Conductance is the property of electrolytes that indicates how easily they can conduct electricity. The conductivity of the electrolyte is the conductance of the volume of the solution with the one mole (1M) of the solution that is placed between two electrodes parallel to each other at a spacing of 1-dm apart. Temperature affects the conductance of the electrolytes.
The results of the experiment show higher conductance in the strong electrolytes than in the weak electrolytes. This is because strong electrolytes highly dissociate in solutions to produce a large number of ions. The mobile ions migrate across the electrodes causing a high conduction of electricity. Weak electrolytes have partial dissociation in solutions generating few mobile ions that cause low conduction of electricity.
The result shows an increase of conductance with dilution in both the strong and weak electrolytes. In the two cases, the degree to which the dilution impacts conductance differs. Increased dilution causes the ions to be farther apart decreasing the inter-ionic forces hence more ions can travel across the electrolyte. Also, the electrolytes undergo a further ionization.
Conclusion
References
Shaw, L. I. (1911). Studies of the electrical conductance of non-aqueous solutions. N.Y. Print
