If the property of a sample of matter does not depend on the amount of matter present, it is an intensive property. Temperature is an example of an intensive property. As another example, consider the distinct but related properties of heat and temperature. A drop of hot cooking oil spattered on your arm causes brief, minor discomfort, whereas a pot of hot oil yields severe burns.
Both the drop and the pot of oil are at the same temperature an intensive property , but the pot clearly contains much more heat extensive property. You may have seen the symbol shown in Figure 4 on containers of chemicals in a laboratory or workplace. Figure 4. The system details flammability, reactivity, health, and other hazards. Within the overall diamond symbol, the top red diamond specifies the level of fire hazard temperature range for flash point. The blue left diamond indicates the level of health hazard.
The yellow right diamond describes reactivity hazards, such as how readily the substance will undergo detonation or a violent chemical change. Each hazard is rated on a scale from 0 to 4, with 0 being no hazard and 4 being extremely hazardous.
While many elements differ dramatically in their chemical and physical properties, some elements have similar properties. We can identify sets of elements that exhibit common behaviors.
For example, many elements conduct heat and electricity well, whereas others are poor conductors. These properties can be used to sort the elements into three classes: metals elements that conduct well , nonmetals elements that conduct poorly , and metalloids elements that have properties of both metals and nonmetals.
The periodic table is a table of elements that places elements with similar properties close together Figure 5. You will learn more about the periodic table as you continue your study of chemistry. Figure 5. The periodic table shows how elements may be grouped according to certain similar properties. Note the background color denotes whether an element is a metal, metalloid, or nonmetal, whereas the element symbol color indicates whether it is a solid, liquid, or gas.
All substances have distinct physical and chemical properties, and may undergo physical or chemical changes. Physical properties, such as hardness and boiling point, and physical changes, such as melting or freezing, do not involve a change in the composition of matter. Chemical properties, such flammability and acidity, and chemical changes, such as rusting, involve production of matter that differs from that present beforehand.
This is relative thermal conductivity. Metal has a higher heat transferability, or thermal conductivity, than wood, letting the heat from your hand leave faster. If you want to keep something cold the best idea is to wrap it in something that does not have a high heat transferability, or high thermal conductivity, this would be an insulator.
Ceramics, and polymers are usually good insulators, but you have to remember that polymers usually have a very low melting temperature. That means if you are designing something that will get very hot the polymer might melt, depending on its melting temperature. Electrical and thermal conductivity are closely related. For the most part good electrical conductors are also good thermal conductors. Many products will contain both conductors and insulators- the conductors take the electricity or thermal energy where it is wanted and the insulators prevent it from getting where it isn't wanted.
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.
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