Why is conductivity a physical property

Familiar examples of physical properties include density, color, hardness, melting and boiling points, and electrical conductivity. We can observe some physical properties, such as density and color, without changing the physical state of the matter observed. Other physical properties, such as the melting temperature of iron or the freezing temperature of water, can only be observed as matter undergoes a physical change. A physical change is a change in the state or properties of matter without any accompanying change in its chemical composition the identities of the substances contained in the matter.

We observe a physical change when wax melts, when sugar dissolves in coffee, and when steam condenses into liquid water Figure 1. Other examples of physical changes include magnetizing and demagnetizing metals as is done with common antitheft security tags and grinding solids into powders which can sometimes yield noticeable changes in color.

In each of these examples, there is a change in the physical state, form, or properties of the substance, but no change in its chemical composition. Figure 1. The change of one type of matter into another type or the inability to change is a chemical property. Examples of chemical properties include flammability, toxicity, acidity, reactivity many types , and heat of combustion. Iron, for example, combines with oxygen in the presence of water to form rust; chromium does not oxidize Figure 2.

Nitroglycerin is very dangerous because it explodes easily; neon poses almost no hazard because it is very unreactive. Figure 2. To identify a chemical property, we look for a chemical change. A chemical change always produces one or more types of matter that differ from the matter present before the change.

The formation of rust is a chemical change because rust is a different kind of matter than the iron, oxygen, and water present before the rust formed. The explosion of nitroglycerin is a chemical change because the gases produced are very different kinds of matter from the original substance.

Other examples of chemical changes include reactions that are performed in a lab such as copper reacting with nitric acid , all forms of combustion burning , and food being cooked, digested, or rotting Figure 3. Figure 3. Properties of matter fall into one of two categories. If the property depends on the amount of matter present, it is an extensive property. The mass and volume of a substance are examples of extensive properties; for instance, a gallon of milk has a larger mass and volume than a cup of milk.

The value of an extensive property is directly proportional to the amount of matter in question. If the property of a sample of matter does not depend on the amount of matter present, it is an intensive property.

Pore-fluid conductivity increases as the concentration of dissolved ions increases. This implies that rocks containing more brackish pore fluid are more conductive than rocks containing fresh-water. For rocks with high tortuosities, the path the current must take to get through the rock is very indirect. As a result, conduction is inefficient, and the rock is more resistive. Electrical current within a rock will choose not to flow through the pore-space if the rock forming minerals are more conductive.

This occurs frequently in ore-bearing rocks due to the presence of metal-oxides magnetite, illmenite, specular hematite , metal-sulphides pyrite, pyrrhotite, galena and native metals gold, silver, copper.

One exception is graphite, which despite being entirely comprised of carbon, is very conductive. As expected, the conductivity increases as the concentration of conductive minerals within the rock increases. GPG 0. From this chart we can infer several things: Massive sulphides and graphite-bearing rocks are by far the most conductive.

Carbonate rocks and unconsolidated sediments are very resistive Weathered igneous and metamorphic rocks are more conductive than unweathered igneous and metamorphic rocks. Intensive properties do not depend on the amount of the substance present. Some examples of intensive properties are color, taste, and melting point.

Extensive properties vary according to the amount of matter present. Examples of extensive properties include mass, volume, and length. Classifying how a substance looks and how it smells does not require changing its composition.

Thus, nitrogen's lack of color and odor are physical properties. In the calculation, the value of SI unit is multiplied by to the value of the conventional unit. Soil electrical conductivity EC is a measure of the amount of salts in soil salinity of soil.

It is an important indicator of soil health. For certain non-saline soils, determining EC can be a convenient and economical way to estimate the amount of nitrogen N available for plant growth. Conductivity is the measure of the ease at which an electric charge or heat can pass through a material.

A conductor is a material which gives very little resistance to the flow of an electric current or thermal energy. Electrical conductivity tells us how well a material will allow electricity to travel through it.

Examples of chemical properties include flammability, toxicity, acidity, reactivity many types , and heat of combustion. Solubility is a physical property. The reason is because it can be determined by simple observation and does not change the chemical composition of the material. For example, when salt dissolves in water, it is still salt. Chemical stability refers to whether a compound will react with water or air chemically stable substances will not react.