What are the physical and chemical properties determined.

There are two definitions of physical properties, one refers to the properties of substances that do not need to undergo chemical changes, and the other refers to the properties that substances exhibit without chemical reactions, which are called physical properties.

The physical properties of substances such as color, smell, state, whether they are easy to sublimate, volatile, etc., can be perceived by people's ears, nose, tongue, body and other senses, and some properties such as melting point, boiling point, hardness, electrical conductivity, thermal conductivity, ductility, etc., can be measured by instruments. There are also some properties that can be obtained and calculated through laboratory data, such as solubility, density, corrosion resistance, etc.

Neither the matter changed before or after the experiment. These properties are all physical.

The properties that matter exhibit when it undergoes a chemical change are called chemical properties. Involves a change in the chemical composition of a substance's molecule (or crystal).

Such as flammability, instability, acidity, alkaline, oxidation, flammability, reduction, complexation, toxicity, thermal stability, corrosiveness, metallic, non-metallic and certain substances react with the phenomenon. The chemical properties of a substance can be known by the method of causing a chemical reaction of a substance.

Anyone who contains "can, easy, can... These words in the sentence can be said to be nature!

Physical properties: The properties of matter that can be expressed without chemical changes are called physical properties.

Water-soluble (e.g. sugar can be dissolved in water.) ）；Volatility; Electrical conductivity··· Chemical substances: The properties of substances that are exhibited when they undergo chemical changes are called chemical properties.

flammability (e.g. matches can burn); corrosive; Toxic; Stability...

Chemical properties correspond to chemical changes, such as oxidation and reduction, flammability, thermal stability, acidity and alkalinity, etc.

Physical properties such as color, state, odor, density, hardness, melting boiling point, electrical conductivity, etc.

The concepts of physical and chemical properties are as follows:

1. Physical properties are the properties of substances that do not need to undergo chemical changes, such as color, state, odor, density, melting point, boiling point, hardness, solubility, ductility, electrical conductivity, thermal conductivity, etc., which can be sensed or measured by instruments.

2. Chemical properties are the properties of substances that are exhibited in chemical changes. For example, the chemical properties of the substance category: acidic, alkaline, oxidizing, reducible, thermal stability and some other properties.

Physical properties of jadeite (1) Color: Gem quality is mostly green, and there are also red, purple, yellow, white and colorless. (2) Hardness:

6~7。(3) Density: ,—about.

4) Fracture: granular or jagged. (5) Toughness:

Good. (6) Transparency: translucent to opaque, transparency is commonly known as "water head" or "species" in the jargon.

7) Gloss: glass to grease luster. (8) Refractive index:

Absorption spectrum: 437nm is the characteristic absorption spectrum line of jadeite, that is, iron absorption. The 630nm, 660nm, and 690nm lines are the characteristic absorption lines of chromium color.

10) Most of the natural jadeite has no fluorescence, and a few green jadeites have weak green fluorescence. In white jadeite, feldspar can be seen with weak blue fluorescence after kaolinization. (11) Natural green jadeite does not change color under the Charles color filter.

12) Emerald: The jadeite mineral is a reflective "fly wing" of the cleavage plane, which is related to the size of the crystalline particles.

Chemical composition of jadeite: The main ingredient is sodium aluminum silicate, which may contain trace elements such as calcium, chromium, nickel, manganese, magnesium, and iron.

No, you cannot. Jadeite can not accept high temperatures, although the melting point of jadeite is very high, but it does not mean that the quality will not be damaged, after high temperature jadeite both color and texture will be affected, resulting in a great discount in the value of jadeite, so it should be avoided as much as possible in daily life. In addition, the jade ornament should be removed before entering the sauna.

High temperatures cause jadeite to lose its warm moisture, drying out its germplasm and lightening its color. Therefore, for valuable jadeite jewelry, it is best to remove it when cooking. Jadeite can not accept high temperatures, jadeite can not be exposed to the sun or high temperature roasting, will make jadeite lose moisture or wax on the surface volatilization and dry crack.

Try not to wear jadeite jewelry when visiting beaches and other places with strong sunshine. When the jadeite is boiled in boiling water, the jadeite will crack under the condition of thermal expansion and cold contraction, and even if the jadeite is not cracked, the wax layer applied on its surface will be volatilized, and the wax layer will be cleaned, which is very unfavorable for the maintenance of jadeite.

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1. Physical properties.

Physical properties refer to properties that can be exhibited without chemical changes, such as color, state, odor, melting point, boiling point, hardness, density, etc. For example, nitrogen is a colorless, odorless gas with low melting and boiling points.

2. Chemical properties.

The properties of substances exhibited in the changes of chemical wheel source are called chemical properties, such as flammability, stability, reduction, oxidation, etc.

Chemical properties need to undergo chemical changes to manifest, such as hydrogen is flammable, this property can only be manifested in the chemical reaction of hydrogen combustion, so it is a chemical property; Physical properties, on the other hand, are physical quantities that can be perceived and measured.

3. Chemical changes.

When the change produces other substances, it is called a chemical change, also called a chemical reaction. For example, the burning of firewood and the rusting of steel all form new substances, both of which are chemical changes.

In the process of chemical change, in addition to the formation of other substances, there are also some phenomena such as heat release, luminescence, discoloration, gas release, precipitation, etc., which can often help us judge whether chemical changes have occurred, but they are not the essence of change.

4. Physical changes.

The absence of other substances is called a physical change. For example, the vaporization of liquid water into water vapor by heat is a physical change.

The essential difference between physical change and chemical change is whether or not other substances are formed. For example, the chemical change of sulfur dioxide produced by sulfur combustion is a chemical change in the wax state, and the absence of other substances when the lamp is energized and emitted is a physical change.

Physical change is related to chemical change, and physical change occurs at the same time as chemical change occurs, but chemical change does not necessarily occur in the process of physical change.

1) Do not use the phenomenon of chemical change as the basis for judging physical and chemical changes.

2) The difference between the change of matter and the properties of matter.

A change in matter, whether physical or chemical, refers to a dynamic process, while the properties of matter, whether physical or chemical, refer to properties specific to matter.

Physical properties refer to the density, melting point, boiling point, ductility, solubility, etc. of a substance.

The former is chemical.

The following are: Physical properties of table salt (sodium chloride):

Pure sodium chloride crystal is a colorless and transparent cubic crystal, due to the presence of impurities, the sodium chloride in general is a white cubic crystal or a fine crystal powder, the specific gravity is, the melting point is 801, the boiling point is 1442, the taste is salty, the pH value is neutral, easy to dissolve in water and glycerol, difficult to dissolve in ethanol.

The properties of a substance that manifest itself in chemical changes are called chemical properties, for example, when a piece of paper burns, it means that it is flammable. Note that if you say "this piece of paper burns."", which is a chemical change. If it is said'This paper can burn", that is, the chemical properties.

The physical properties that matter exhibit without the need for chemical changes are called. It is a property that can be perceived through the five senses or can be measured with an instrument. The color, state, smell, hardness, melting point, boiling point, density, etc., of an object are all physical properties.

Air, for example, is colorless, gaseous, and odorless. This is the physical nature of air.

Physical Properties: Properties of a substance that exhibit without a chemical changeChemical Properties: Properties of a substance that exhibit when a chemical change occursChemical changes produce new substances.

For example, the burning of magnesium belts produces a white powder.

Physical change is only a change in form, and there is no change in new matter, such as a change in three states

Volatilization, crushing,

Dissolution, brine evaporation,

Diffusion. When distinguishing between chemical and physical properties, the main thing is to see whether new substances are generated.

Chemical properties The properties that manifest themselves in chemical changes.

Chemical changes are commonly used;

But, can, easy, will

Make, come, etc.

Such as: flammability, oxidation, reduction and stability.

Physical Properties: The properties of a substance that do not require a chemical change to manifest itself.

Such as: color, taste, state, two points (melting point.

boiling point), two degrees (hardness and density), five properties (electrical conductivity, thermal conductivity, rolling resistance, volatility and solubility).

Physical properties: silvery-white, melting point is 660 degrees Celsius, low density (an important metal material for the manufacture of various lightweight structures), electrical conductivity, thermal conductivity, good ductility, low strength.

Chemical properties: electrolytic alumina to form aluminum and oxygen, corrosion resistance (aluminum reacts with oxygen to form a dense alumina film, thus corrosion resistance), aluminum reacts with hydrochloric acid to produce hydrogen and aluminum chloride.

Silvery-white metal with a melting point of 660 degrees Celsius.

Metal conductivity, heat transfer.

Low ductility strength.

Aluminium is made from electrolytic alumina.

Corrosion resistance.

and oxygen to form a dense film.

Aluminum reacts with hydrochloric acid to produce hydrogen and aluminum chloride.