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I. Basic concepts and basic theories
(I) Material changes and properties
1. Material change: Physical change: No change in other substances. Chemical change: other produced
Chemical and physical changes often occur simultaneously. Physical changes must be accompanied by physical changes;
Physical changes, not necessarily chemical changes at the same time. The three-state change of matter (solid, liquid, gas) is a physical change. substance
When a physical change occurs, only the interval between the molecules changes, but the molecule itself does not change; a chemical change occurs
When the molecule is destroyed, the molecule itself changes. Characteristics of chemical changes: Changes in other substances are generated.
2. The nature of matter (the words "can" and "may" are often used in sentences describing nature)
Physical properties: color, state, odor, melting point, boiling point, hardness, density, solubility.
Chemical properties: Properties exhibited through chemical changes. Such as reducing, oxidizing, acidic, alkaline, flammable,
The chemical nature of an element is most closely related to the outermost electron number of the atom. The number of electrons in the outermost layer of the atom determines the transformation of the element
学 性。 Nature.
(II) Classification of substances
Metallic simple substance mixture
Rare gas oxide
Element type Inorganic acid Other oxides
3. Mixture: It is a mixture of two or more substances (or composed of different substances). For example, air,
Solution (hydrochloric acid,
Clarified lime water, iodine, mineral water), minerals (coal, petroleum, natural gas, iron ore, limestone), alloys (raw
Note: The mixture of oxygen and ozone is a mixture, and the mixture of red and white phosphorus is also a mixture.
Pure substances and mixtures are independent of the type of constituent elements. That is, an elemental substance may be pure or mixed
Substances, substances consisting of multiple elements may be pure or mixtures.
4. Pure: Made of one substance. For example: water, mercury, blue alum (CuSO4 · 5H2 O) are pure
Ice mixed with water is pure. The names "a certain" and "a certain acid" are pure substances and compounds.
5. Elemental substance: pure substance composed of the same (or one) element. For example: iron oxygen (liquid oxygen), hydrogen, mercury.