What is Conductivity?
Conductivity is inversely proportional to resistance. This is the property of a metal to conduct current when voltage i.e, potential difference is passed through it. Here, resistance is measured in ohms whereas conductivity in mhos. As such, ohm becomes mho because of the applied condition.
What is Conductivity?
Electric metals and solutions of ionic salts in water are good conductors. Even though the human body has high resistance, it still conducts electricity, so we get electric shock.
Simply, the Ohm’s law can define Conductivity as:
V=IR
Where,
R is resistance,
I is current and
V is voltage present in a material
From the above formula, conductivity depends on the number of charge carriers (electrons) in the material and their mobility. In metal, it is assumed that all outer electrons are free to carry charge. Further, impedance for flow of charge is mainly due to electrons bumping each other. Hence, for metal, as the temperature increases, the resistance of the material increases. Here, electrons bump into each other more as they move faster.
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Insulators are tightly bound electrons so that nearly no electrons flow occurs; as a result, they offer a high resistance to charge flow. Free electrons are required for conductance.
The below diagram shows how conductivity of conjugated polymers like polyacetylene can vary from being an insulator to a conductor:
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Conductivity Formula
The formula for conductivity is the inverse of the resistivity that is:
σ=1/ρ
Here
σ = refers to electrical conductivity
ρ = refers to resistivity
Water Conductivity Units
The ability of the substance to conduct or transmit heat, electricity, or sound is known as conductivity. Its SI unit is Siemens per meter
S/m
S/m, U.S customary unit is milliohms per centimeter
mmho/cm, and is denoted by k or s.
Siemens per meter (S.m−1) is conductivity unt. It is also referred to as mho- that is reciprocal of Ohm, and this is incidental by spelling Ohm backwards.
Also, conductance is reciprocal of resistance, and one Siemens is equivalent to reciprocal of one Ohm.
Conductivity of Water
The measurement of the ability of water to pass electrical flow through it is known as conductivity of water. It directly depends on the concentration of conductive ions present in water. The sources of origin for conductive ions are the inorganic material, such as chloride, carbonate, alkalis and sulfide compounds and dissolved salts.
Conductivity of water is also known as the degree to which water conducts or transmits electricity or heat or sound in it, and is denoted by s or k.
Multiple units can be used to measure the conductivity of water, some of which are mentioned below.
Units
Conductance and Conductivity
Conductance
One must first understand the resistance of an object to understand conductance. Resistance is an elemental property that works in areas of electronics & electricity.. The resistance of a substance tells us how hard it is for an electrical current to flow through it. Also, electrical conductance is considered as a property of the component itself.
Conductivity
There are various things upon which the resistance of a component depends like the conductor's length, area of conductor, and the conductor's material. The conductivity of a material is reciprocal to resistivity and is denoted by the Greek letter σ. Conductivity is a specific property of the material at a given temperature.
Electrical Conductivity of Water
The ability of water to conduct an electric current is known as EC or Electrical conductivity of water. Chemicals or salts break down and dissolve in the water as positive and negative charged ions and these free ions in water conduct electricity. As a result, water electrical conductivity depends upon the concentration of ions.
To calculate the EC of water salinity and total dissolved solids are used, it helps to indicate the water's purity. The conductivity is less for purer water. For example, distilled water acts as an insulator, whereas saltwater is a very efficient electrical conductor.
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Sodium, potassium, calcium, and magnesium are major positively charged ions that affect the conductivity. Similarly, chloride, carbonate, sulfate, and bicarbonate are major negatively charged ions.
Whereas, nitrates and phosphates are minor contributors to conductivity, but are important biologically. Rain, geology, and evaporation are natural impacts of EC in water. Human impacts include road salt, septic/landfill leachate, impervious surface runoff, and agricultural runoff.
Water Conductivity's Importance
A number of measures must be kept to properly ensure that fish and other species in the water remain healthy. Water conductivity, which refers to the degree to which water can carry electricity, is one of these measures. How well electricity can travel through water determines the conductivity of electricity in the water. If you try to carry electricity through pure water, you will not be able to since pure water contains very few ions. Water conductivity is increased when there are large numbers of ions present.
Water conductivity is important for a variety of reasons. In fact, while attempting to determine the quality of water, it is one of the most typical measurements done. In most cases, conductivity measurements are used to calculate total dissolved solids and salinity in water. Conductivity measurements are done on a regular basis in many bodies of water to ensure that the water quality is maintained and that the plants and animals in the water are not harmed. When conducting conductivity measurements on a regular basis, the results should be generally constant. However, once excessive levels of pollution enter the water, evaporation happens, or natural floods occur, these measurements may fluctuate significantly. These occurrences can have a significant impact on the overall water quality.
FAQs on Conductivity of Water
1. What is the Difference Between Conductance and Conductivity?
A brief difference between conductance and conductivity is given below:
Conductance is the property of components, whereas conductivity is the property of material.
Conductance depends on dimensions of conductor, whereas conductivity does not depend on the dimensions.
Conductance is measured in Siemens; whereas SI unit of conductivity is Siemens per meter.
2. Is Pure Water a Good Conductor of Electricity?
Pure water isn't a good conductor of electricity since electrical current is transported by ions present in solution. With the rise in concentration of ions, conductivity increases. Hence conductivity increases as water dissolves ionic species.
3. What is Specific Conductance?
Measurement of conductivity made at a specific temperature of 25° C is known as Specific conductance. This is known as a standardized method of achieving conductivity. Since the temperature of the water affects the conductivity reading, reporting conductivity at about 25° C allows the data to be compared easily. The specific conductance is measured in US/cm at about 25° C temperature.
When measurement of conductivity is accomplished at 25° C temperature, it is known as specific conductance. If the measurement is done at different temperatures and is subjected to 25° C temperature, then it is known as temperature coefficient.
4. What are the Types of Conductivity?
The types of conductivity are referred in point wise below:
Electric Conductivity - The measures to know the ability of the material to conduct electric current.
Electrolytic Conductivity - The electrical conductivity of electrolyte in solution
Ionic Conductivity - Electrical conductivity taking place in ions moving position in a crystal lattice at solid-state
Hydraulic Conductivity - The property of porous material ability to transmit water.
Thermal Conductivity - The intensive property of material that indicates its ability to conduct heat.
5. What is Water conductivity?
Resistance and conductivity are inversely proportional. When voltage is applied to a material, it has the property of allowing an electric current to travel through it. The units of resistance and conductance are ohms and mhos, respectively. (Because of the applied conditions, ohms become mhos). The SI unit for conductivity is S/m, while resistivity is measured in m.
The conductivity of water, or the degree to which water conducts or transmits electricity, is defined as the capacity of water to transfer electrical current through it. It is abbreviated as S. It is directly proportional to the concentration of conductive ions in the water. Conductive ions are produced by inorganic elements such as chloride, carbonate, and alkalies, as well as dissolved salts.
6. What are the factors affecting the conductivity of water?
Following are the factors affecting the conductivity of water:
The kind of substance that dissolves in water.
The temperature
The amount of ions present in the solution. (As the quantity of ions increases, so does the conductivity.) The salinity and conductivity values drop when the input is freshwater.
Water's typical conductivity is:
5.5*10-6 S/m ultra pure water
0.0005-0.0008 s/m tap water
5 s/m in seawater
7. Why does distilled water not conduct electricity?
Distilled water is the purest type of water available. It is used in chemical processes because it is ion-free. Distilled water does not carry electricity because there are no ions to conduct electricity. Tap water, on the other hand, includes ions that carry electricity, such as magnesium(II), calcium(II), and others. Even precipitation includes ions that conduct electricity (owing to the acidic quality of the rain due to pollution in the air).
8. How can conductivity and salinity be measured?
The ability of an electrical current to flow between two different metallic plates can be used to measure conductivity. Electrodes are the metal plates that make up the electrodes. Any dissolved salts in the water will begin to move towards the plate that is charged in the opposite direction. The vast majority of probes used to detect water conductivity are made up of cells with four electrodes. Two of the electrodes measure the water current, while the other two focus on keeping the current constant.
In terms of salinity, doing a chemical analysis to detect the amounts of various ions found in the water, which include anything from calcium and chloride to carbonate and sodium, is likely the best method for calculating and determining salinity. Chemical analysis is quite effective in determining salinity, but it is also very expensive and time-consuming. To prevent these problems, you should compute salinity using your conductivity measurements.
9. Where can I find notes and questions on Conductivity of Water?
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