How to quickly distinguish between mixtures, purities, elementals, compounds, oxides

Oh, I seem to have forgotten almost everything I have learned. My answer may not be accurate.

Mixtures, purities are distinguished macroscopically.

Mixture, that is, a variety of items mixed together, such as tea, there is water and tea leaves, is a mixture.

A pure substance is a single item, such as water or tea, that is separated separately and is pure.

Elemental, compound, oxide are microscopically distinguished.

Elemental, a substance with only one element, such as single carbon, is a substance with only carbon atoms, and like pure oxygen, it is composed of only oxygen molecules. Substances that consist of the same structure, atoms, or molecules of only one element are elemental.

A compound is a substance composed of atoms or molecules of different substances, or it can be a substance composed of different structures of the same atom or molecule.

Oxides are easy to separate, first of all, they should contain oxygen, and then they are compounds, and such substances are oxides.

To quickly distinguish, it is necessary to first determine the mixture or pure substance from the macro and microscopic levels, and then further determine whether it is composed of the same element, the composition of different elements is a compound, the compound containing oxygen is an oxide, if it is composed of different structures of the same substance, it is still a compound, otherwise it is a elemental substance.

The point is to distinguish their concepts, you can go to the encyclopedia to view the relevant entries, and the analysis will be more detailed.

A substance composed of the same kind of molecule is called a pure substance. Pure substances include elemental substances and compounds, and pure substances composed of one element are called elemental substances. Pure substances containing different elements are called compounds. A substance that consists of a variety of molecules is called a compound.

There are two pairs of relative concepts that need to be contrasted to memorize.

1. Elemental substances and compounds. Elemental matter is a pure substance composed of only one element. For example, diamond C, oxygen O2, iron Fe, etc.

A chemical compound, a pure substance consisting of two or more elements. For example, table salt NaCl, water H2O, etc.

2. Mixtures and purifiers. Pure matter, which is composed of only one substance. For example, table salt, NaCl, oxygen, O2, etc.

A mixture, consisting of two or more substances. For example: salt water, NaCl H2O, air O2, CO2, N2, etc.

It should be noted that if there is a mixture of different substances composed of the same element, it is not a pure substance, but only a mixture. For example, diamond and graphite are both composed of carbon, but because the structure is different, they are different substances, and they are mixed just a mixture. Water and ice, on the other hand, are both H2O but different in form, so ice water is pure.

3. Oxide, composed of two elements, one of which is a pure substance of oxygen. In other words, oxygen is made up of one other element. Such as water H20, hydrogen peroxide H2O2, carbon dioxide CO2, copper oxide Cuo, etc.

Substances are divided into mixtures and purities.

A mixture is a mixture of two or more substances [consisting of two or more pure substances (elemental substances or compounds)]. The mixture does not have a chemical formula. There is no fixed composition and properties, and each element or compound retains its original properties.

The mixture can be physically separated from the substance [1]. It is not chemically synthesized.

Such as: air containing oxygen, nitrogen, noble gases, carbon dioxide and other gases, petroleum containing various organic substances (**), natural water, solutions, muddy water, milk, alloys, lime fuel (coal, natural gas), limestone, seawater, salt water, ......

Pure substances are divided into compounds and elemental substances.

A compound is a pure substance composed of atoms of two or more elements (referring to atomic species of different elements). It refers to a pure substance (as distinct from an elemental substance) produced from a chemical reaction.

Compounds have certain properties and usually also have a certain composition.

For example, water is a compound, liquid at room temperature, boiling point 100; , freezing point 0, is composed of two elements, hydrogen and oxygen. 1 water molecule H2O is made up of 2 hydrogen atoms and 1 oxygen atom.

Example: Sodium chloride (NaCl) is a chemical compound formed by the chemical reaction (neutralization reaction) of hydrochloric acid (HCl) and sodium hydroxide (NaOH). HCl(AQ) +NAOH(AQ) Qingpei NaCl(AQ) +H2O(L).

A pure substance composed of elements called elemental.

A substance composed of atoms of an element that exists in a relatively stable free form. For example, oxygen (O2), chlorine (Cl2), sulfur (S8), iron (Fe), etc. Elemental matter and element are two different concepts.

An element is a general term for atoms with the same number of nuclear charges (number of protons). There may be several elements of an element, such as oxygen element, oxygen (O2) and ozone (O3).

Compounds are further divided into a variety of substances, such as oxides.

Oxide refers to a compound composed of two elements, one of which is oxygen, such as carbon dioxide (CO2) and calcium oxide (CAO).

Classification: Oxides can be divided into four categories: acidic oxides, basic oxides, amphoteric oxides and non-salted oxides [1] according to whether they form salts with water and the types of salts generated. (There are also a lot of complex oxides.) ）

Oxides are chemical compounds, (of course, they must be pure). It contains only two elements, one of which must be oxygen (definition) and the other is a metal oxide if it is a metal element; If it is a non-metal, it is a non-metallic oxide.

The pre-defeat ridge of matter is divided into mixtures and purities.

A mixture is made up of a mixture of two or more substances.

Pure matter, on the other hand, contains only one substance.

Pure substances are further divided into compounds and elementals.

There is only one element in the element (the element is separated from the pure substance, and the mixture is not the element, for example, the mixture of golden worm and graphite also contains only one element, but it is not a element).

Whereas, there are two or more elements in the compound.

Compounds are further divided into acids, bases, salts, oxides, and organic compounds.

Oxides are compounds that contain two elements, one of which is oxygen.

Hello, I am a teacher of Xiaodu, and I have provided consulting services to nearly 500 people, with a cumulative service time of more than 100 hours! I've seen your question, and I'm sorting out the answer, it will take about three minutes, please wait a while If my answer is helpful to you, please give it a thumbs up, thank you

Purity: Purity refers to a polymer that consists of a single element or a chemical compound.

2. The nature is different.

Elemental: Elemental matter cannot undergo decomposition reaction.

Compounds: Compounds can undergo decomposition reactions.

Mixture: The mixture has no fixed properties, such as no fixed melting and boiling points.

Pure substance: Pure substance has fixed properties, such as a certain fixed melting and boiling point.

1. Nature.

Elemental: It is a pure substance composed of the same element.

Compound: A pure substance composed of two or more elements.

Mixture: It is a substance formed by mixing two or more substances, and is composed of a fixed substance with fixed physical and chemical properties.

Pure: A polymer composed of a single substance or a chemical compound.

2. Features. Compounds: They have certain properties, which are different from the elements or ions they contain, as well as from other compounds, and usually have a certain composition.

Mixture: There is no fixed chemical formula, no fixed composition and properties, and no chemical reaction occurs between the various components that make up the mixture, leaving them in their original properties. Mixtures can be physically separated from the substances. It is not chemically synthesized.

Pure substance: a substance with a fixed composition and fixed physical and chemical properties; There are special chemical symbols, such as: oxygen, nitrogen, potassium chlorate, etc. are pure.

First, the composition of the elements is different.

1. A mixture is composed of two or more substances.

2. Pure matter is composed of only one substance.

3. A compound is composed of two or more elements.

4. Elemental matter is an elemental composition.

Second, the nature is different.

1. Elemental matter cannot be decomposed by reaction.

2. Compounds can undergo decomposition reactions.

3. Pure matter is composed of the same substance, it has a certain composition, which can be expressed by a chemical formula, and pure matter has certain properties (such as fixed melting and boiling points).

4. The mixture is made up of a mixture of different substances, without a certain composition, and cannot be expressed by a chemical formula. The mixture does not have fixed properties, and each substance retains its original properties (e.g., there is no fixed melting and boiling point).

3. Different examples.

1. Elementality. Common gases are: hydrogen, oxygen, nitrogen, rare gases, etc.; Solids are: carbon, sulfur, phosphorus, iron, aluminum, copper, gold, silver, tungsten, manganese, magnesium, etc.

2. Compounds.

Such as ammonia NH3, methane CH4, phosphorus pentoxide P2O5, carbon disulfide CS2, etc.; Some compounds are composed of atoms, such as silicon dioxide SiO2, silicon carbide SiC, etc.

3. Pure substance.

Such as C, MG, FE, MGO, P, oxygen, nitrogen, potassium chlorate, etc.

4. Mixture.

Such as air containing oxygen (O2), nitrogen (N2), noble gases, carbon dioxide (CO2) and other gases and impurities; Petroleum (**), natural water, solutions, muddy water, milk, alloys, fossil fuels (coal, natural gas, oil), etc., containing various organic substances.

[Elemental].

Definition A pure substance made up of the same element is called elemental.

Note 1Some elements can form several elemental substances. For example, oxygen and ozone are different elements formed by the element oxygen, and diamond and graphite are both different elements formed from the element carbon.

2.Elemental matter is the concrete form in which an element exists in its free state. Water electrolysis can produce hydrogen and oxygen. Based on this, it can only be said that "water contains hydrogen and oxygen", and it cannot be said that "water contains hydrogen and oxygen". Elemental substances cannot undergo decomposition reactions.

Mixture] Definition A substance that is formed by the mechanical mixing of two or several different elemental substances or compounds, is called a mixture.

Note 1A mixture, unlike a compound, has no fixed composition. The components in the mixture still retain their original properties.

2.The components of a mixture can be uniformly dispersed (e.g., solution) or inhomogeneously (e.g., turbid liquid or solid mixture), but do not occur with each other.

Chemical reaction. As the different components attract or repel each other, the overall properties of the mixture may be affected. For example, the total volume of a mixture formed by several liquids is generally not equal to the sum of the subvolumes of the various liquids.

3.The mixture can be separated by physical methods (such as crystallization, sublimation, distillation, extraction, etc.) according to the different physical properties of the components it contains (such as solubility, boiling point, density, magnetism, etc.).

4.In middle school chemistry in China, mixtures have been written as mixtures for a long time, and mixtures have been written as mixtures, but now they have been corrected.

Definition of Pure Substance A substance that consists of only one elemental substance or one compound is called a pure substance.

Note 1Pure substances have a fixed composition and can be expressed by a certain chemical formula. Pure matter cannot be separated by physical methods, but only by chemical methods.

2.In fact, there is no such thing as a completely pure substance. A substance that contains impurities in quantities that do not cause harmful effects in production and scientific research can be regarded as pure.

Generally speaking, there is a difference in the purity of pure substances. For example, chemical reagents can be divided into industrial pure, experimental pure (chemically pure, analytical pure, excellent pure) and ultra-pure according to their purity from low to high.

3.The purity grade of the reagent selected in the experiment is too high, which will cause unnecessary waste due to too high **; The purity grade of the selected reagent is too low, which will cause the experiment to fail due to the interference of impurities in the reagent. Reagents or raw materials of comparable purity should be selected according to the application.

Definition of Compound A pure substance composed of different elements is called a compound.

Note 1Compounds generally have a fixed composition. The composition of a compound can generally be expressed by a chemical formula.

2.Compounds have definite physical and chemical properties that differ from the properties of their constituent elements.

3.The elements in a compound cannot be separated by simple mechanical or physical methods, but must be separated by chemical methods.

If a substance contains multiple components (containing multiple molecules, which cannot be expressed by one chemical formula), it is a mixture; If it contains an ingredient (containing a molecule, which can be expressed by a chemical formula), it is pure.

If there is only one element in a pure substance (e.g., hydrogen H2 contains only hydrogen element), it is elemental, and if it contains multiple elements (e.g., water H2O contains hydrogen and oxygen), it is a compound.