26-08-2014, 03:06 PM
Variation of
Conductance with
Temperature in
Electrolytes
[attachment=67067]
Acknowledgements
"There are times when silence speaks so much more loudly than
words of praise to only as good as belittle a person, whose words
do not express, but only put a veneer over true feelings, which
are of gratitude at this point of time."
I would like to express my sincere gratitude to my chemistry
mentor Mrs Janet Garrison, for her vital support, guidance and
encouragement - without which this project would not have
come forth. I would also like to express my gratitude to the staff
of the Department of Chemistry at South Park Elementary for
their support during the making of this project
Aim
To find the variation of conductance with temperature in
electrolytes
Apparatus
Glass beaker, CuSO4 solution, Cu electrodes, ZnSO4 solution, Zn
electrodes, rheostat, battery eliminator, water, burner,
thermometer, flask, ammeter, voltmeter
Important Terms
Conductance: The property of ease of flow of electric
current through a body is called conductance.
Resistance: The obstacle offered to the flow of electric
current is called resistance.
Electrolysis: The operation in which electricity causes a
chemical reaction is called electrolysis.
Ohm's Law: This law states that the current flowing
through a resistance is directly proportional to the potential
difference applied across it's ends, at constant temperature
and pressure.
V = I x R
Faraday's Laws:
First Law: The mass of a substance produced or
consumed in electrolysis is directly proportional to the
quantity of charge passing through it.
m Q
or, m = Z × I × t
where, Z is electrochemical equivalent; I is current; t is
time in seconds; Q is charge.
Second Law: The mass of substance produced in
electrolysis directly proportional to its equivalent mass.
W1 / E1 = W2 / E2 = W3 / E3...
Third Law: The mass of a substance produced in
electrolysis is directly proportional to the number of
electrons per mole needed to cause desired change in
oxidation state.
Conductivity
When voltage is applied to the electrodes immersed into an
electrolyte solution, ions of electrolyte move, and thus, electric
current flows through the electrolytic solution. The electrolytic
solution and the metal conductors exhibit resistance to the
passage of the current; both of which obey Ohm's law.
The reciprocal of resistance is called electrical conductance. The
unit of electrical conductance is Siemens (S) or ohm-1 or mho.
If a solution is placed between two parallel electrodes having
cross sectional area A and distance L apart then the resistance is
given by
R = 1 / C
ρ (called 'rho') is known as resistivity. Its reciprocal gives the
conductivity of the solution, which is denoted by κ (called
'kappa'). Its unit is Siemens/meter.
Κ = 1 / R * L / A
L / A is a fixed quantity for a cell and is called the 'cell constant
Factors Affecting Electrical
Conductivity
The factors which affect the electrical conductivity of the
solutions are:
Inter-ionic attraction: It depends on solute- solute
interactions.
Solvation of ions: It depends on solute-solvent
interactions.
Viscosity of the solvent: It depends on solvent-solvent
interactions.
Physical Constants
For the purpose of accuracy and convenience, some important
aspects of the electrolyte process are kept constant in the
experiment as their variation might affect the conductivity of the
electrolyte. They are:
Voltage
Nature of electrodes
Size of electrodes
Separation between the electrodes
Concentration of the electrolytes
Nature of the electrolytes
Resistance in the circuit iCB
Conclusion
On heating a solution, it is known that viscosity gradually
decreases, with decrease in viscosity, the speed and movement
of the ions increases. In other words, the conductance of the
electrolyte increases with increases in temperature. Hence, the
result of the experiment agrees with reasoning.
Precautions
Variation of resistance due to one of the factors should be
kept constant.
The electrodes used in each case should always be kept
parallel to each other.
The solution should be kept undisturbed throughout the
experiment.
For each observation, three readings are taken and the
mean value is considered. iCBS
Conductance with
Temperature in
Electrolytes
[attachment=67067]
Acknowledgements
"There are times when silence speaks so much more loudly than
words of praise to only as good as belittle a person, whose words
do not express, but only put a veneer over true feelings, which
are of gratitude at this point of time."
I would like to express my sincere gratitude to my chemistry
mentor Mrs Janet Garrison, for her vital support, guidance and
encouragement - without which this project would not have
come forth. I would also like to express my gratitude to the staff
of the Department of Chemistry at South Park Elementary for
their support during the making of this project
Aim
To find the variation of conductance with temperature in
electrolytes
Apparatus
Glass beaker, CuSO4 solution, Cu electrodes, ZnSO4 solution, Zn
electrodes, rheostat, battery eliminator, water, burner,
thermometer, flask, ammeter, voltmeter
Important Terms
Conductance: The property of ease of flow of electric
current through a body is called conductance.
Resistance: The obstacle offered to the flow of electric
current is called resistance.
Electrolysis: The operation in which electricity causes a
chemical reaction is called electrolysis.
Ohm's Law: This law states that the current flowing
through a resistance is directly proportional to the potential
difference applied across it's ends, at constant temperature
and pressure.
V = I x R
Faraday's Laws:
First Law: The mass of a substance produced or
consumed in electrolysis is directly proportional to the
quantity of charge passing through it.
m Q
or, m = Z × I × t
where, Z is electrochemical equivalent; I is current; t is
time in seconds; Q is charge.
Second Law: The mass of substance produced in
electrolysis directly proportional to its equivalent mass.
W1 / E1 = W2 / E2 = W3 / E3...
Third Law: The mass of a substance produced in
electrolysis is directly proportional to the number of
electrons per mole needed to cause desired change in
oxidation state.
Conductivity
When voltage is applied to the electrodes immersed into an
electrolyte solution, ions of electrolyte move, and thus, electric
current flows through the electrolytic solution. The electrolytic
solution and the metal conductors exhibit resistance to the
passage of the current; both of which obey Ohm's law.
The reciprocal of resistance is called electrical conductance. The
unit of electrical conductance is Siemens (S) or ohm-1 or mho.
If a solution is placed between two parallel electrodes having
cross sectional area A and distance L apart then the resistance is
given by
R = 1 / C
ρ (called 'rho') is known as resistivity. Its reciprocal gives the
conductivity of the solution, which is denoted by κ (called
'kappa'). Its unit is Siemens/meter.
Κ = 1 / R * L / A
L / A is a fixed quantity for a cell and is called the 'cell constant
Factors Affecting Electrical
Conductivity
The factors which affect the electrical conductivity of the
solutions are:
Inter-ionic attraction: It depends on solute- solute
interactions.
Solvation of ions: It depends on solute-solvent
interactions.
Viscosity of the solvent: It depends on solvent-solvent
interactions.
Physical Constants
For the purpose of accuracy and convenience, some important
aspects of the electrolyte process are kept constant in the
experiment as their variation might affect the conductivity of the
electrolyte. They are:
Voltage
Nature of electrodes
Size of electrodes
Separation between the electrodes
Concentration of the electrolytes
Nature of the electrolytes
Resistance in the circuit iCB
Conclusion
On heating a solution, it is known that viscosity gradually
decreases, with decrease in viscosity, the speed and movement
of the ions increases. In other words, the conductance of the
electrolyte increases with increases in temperature. Hence, the
result of the experiment agrees with reasoning.
Precautions
Variation of resistance due to one of the factors should be
kept constant.
The electrodes used in each case should always be kept
parallel to each other.
The solution should be kept undisturbed throughout the
experiment.
For each observation, three readings are taken and the
mean value is considered. iCBS