8． base
A part of atoms or atomic groups with special properties in a compound, or the remaining atomic groups after removing certain atoms or atomic groups in the compound molecule.
(1) The functional group of organic matter is the group that determines the main properties of the substance, such as the hydroxyl group of alcohol (— OH ) and the carboxyl group of carboxylic acid (— span7 spanspan CO OH) .
（2）甲烷（ CH 4 ）分子去掉一个 氢原子 后剩余部分（ · CH 3 ） contains unpaired valence electrons,Called methyl or methyl radical, also includes single-atom radicals ( · Cl).
9 ． Physical and chemical properties
9． Physical and chemical changes
Physical changes: Changes that do not generate other substances , are only changes in the form of substances.
Chemical change: other substances are generated during the change, also called chemical reaction.
Characteristics of chemical changes: new substances are formed with exotherm, luminescence, discoloration, etc. Electronics etc.The difference between the two is: the former does not generate new substances, but only changes in the form and state of substances.
10 ． Solubility w.w.w.k.s.5.u.c.o.m
refers to the ability of a substance to dissolve in a certain solvent. For example, sodium chloride is easily soluble in water, but insoluble in organic solvents such as absolute ethanol and benzene. Elemental iodine has poor solubility in water, but is easily soluble in organic solvents such as ethanol and benzene. Phenol is only slightly soluble in water at room temperature. When the temperature is greater than 70 ℃, it is miscible with water in any ratio (the melting point of phenol is 43 ℃, and 70 ℃ liquid). Using the difference in solubility of substances at different temperatures or in different solvents, mixtures can be separated or substances can be purified.
In the process of dissolving the above substances, the chemical composition of the solute and solvent does not change, and the solute and solvent can be separated by simple physical methods. There is also a dissolution in a completely different sense. For example, limestone is dissolved in hydrochloric acid, iron is dissolved in dilute sulfuric acid, silver hydroxide is dissolved in ammonia water, etc. In such dissolution, the chemical composition of the substance has changed, and the dissolved substance cannot be purified by simple physical methods.
11． Liquefaction
Refers to the phenomenon that a gaseous substance is transformed into a liquid under conditions of decreasing temperature or increasing pressure.In the production process of the chemical industry, in order to facilitate the storage and transportation of certain gaseous substances, gaseous substances are often liquefied. The liquefaction operation is to pressurize while cooling down. The equipment and containers used for liquefaction must be able to withstand high pressure to ensure safety. The uses of several commonly used gases after liquefaction are shown in the table below.
12． Metallicity
of an element Metallicity generally refers to the ability of an element's atoms to lose valence electrons. The easier the atoms of the element lose electrons, the stronger the metallicity of the element, the easier its element is to replace the hydrogen in water or acid to become hydrogen , and the stronger the alkalinity of the hydrate of its highest valence oxide. The larger the atomic radius of an element, the less valence electrons, and the easier it is to lose electrons. Among the various stable isotopes, cesium is the most metallic, and cesium hydroxide is also the most basic. In addition to metallic elements showing different strengths of metallicity, some non-metallic elements also exhibit certain metallicity, such as boron, silicon, arsenic, tellurium and so on.
13． non-metallicity
refers to the ability of an element's atoms to gain (absorb) electrons in a reaction. The atoms of the element get electrons more easily in the reaction. The stronger the non-metallicity of the element is, the easier the element is to combine with H 2 , the more stable the generated hydride , the more acidic the hydrate (oxyacid) of its highest valence oxide is. Strong (except oxygen element, fluorine element ).
Fluorine is known to be the most reactive non-metallic element.It reacts violently with hydrogen in the dark, hydrogen fluoride is the most stable hydride. oxygen element is second only to fluorine in non-metallicity. In addition to fluorine and oxygen elements, chlorine element is also very non-metallic. Its highest valence oxide (Cl 2 O 7 ) hydrate - perchloric acid ( HClO 4 ) is the strongest known oxyacid.
14． Oxidability
The ability of a substance (element or compound) to gain (attract) electrons in a chemical reaction is called the oxidability of a substance. Non-metal elements, compounds with high valence of metal elements, some oxo acids and their salts generally have strong oxidizing properties.
The oxidizing properties of non-metallic elements are very similar to those of elements. Fluorine is the most oxidizing non-metallic element. The oxidative properties are as follows: ①The oxidizing property of active metal cation is weaker than that of inactive metal cation, such as Na + ＜ _ Ag + valence; in metal,高价态的氧化性强于低价态的氧化性，如 Fe 3+ ＞ Fe 2+ ， MnO 4 − ＞ MnO 4 2 − ＞ MnO 2 ； ③同种元素含氧酸的氧化性往往是价态越高，氧化性越强，如 HNO 3 ＞ HNO 2 ，浓度越大，氧化性也越强，如浓 HNO 3 ＞稀 HNO 3 , 浓_ span14span H 2 SO 4 span7spa n > thin H 2 SO 4 .然而，也有例外，如氯元素的含氧酸，它们的氧化性强弱顺序是 HClO ＞ HClO 2 ＞ HClO 3 ＞ HClO 4 .
15． Reducibility
The ability of a substance to lose electrons in a chemical reaction is called the reducibility of the substance. Metal elements, most non-metal elements and compounds containing elements in low valence state have strong reducibility. The strength of a substance's reducibility depends on the substance's ability to lose electrons in a chemical reaction.
The stronger the metallicity of the element, the stronger the reduction of the elemental metal, and the order of the reduction of the elemental metal is basically the same as that of the metal activity of . The weaker the non-metallicity of the element, the stronger the reducibility of the non-metallic element. If an element has substances with multiple valence states, generally speaking, the lower the valence state, the stronger the reducibility.如含硫元素不同价态的物质的还原性： H 2 S ＞ S ＞ SO 2 ；含磷元素物质的还原性 PH 3 ＞ P 4 ＞ PO 3 3 − ；铁及其盐的还原性： Fe ＞ Fe 2+ 等。
16． Volatility
The ability of a liquid substance to transform into a gaseous state at temperatures below the boiling point, and the ability of some gaseous solutes to escape from solution. Most of the substances with strong volatility are some low-boiling liquid substances, such as ethanol, ether , acetone, chloroform, carbon disulfide , etc. In addition, ammonia water, concentrated hydrochloric acid, concentrated nitric acid , etc. all have strong volatility. When these substances are stored, they should be kept tightly closed and kept away from heat sources to prevent accelerated volatilization by heat.
17． Sublimation
Under the condition of heating, the solid matter changes directly into the gaseous state without going through the liquid state. Common sublimable substances are I 2 , dry ice (solid CO 2 2 ), sublimated sulfur, red phosphorus , gray arsenic, etc.
18． Stability
is a chemical property of a substance. It reflects the ease with which a substance undergoes a chemical reaction under certain conditions. Stability can be divided into thermal stability, photochemical stability and redox stability.
The less reactive the substance,Its chemical stability is better. For example, benzene is generally chemically stable, so benzene is often used as an extractant and a medium for organic reactions. Many reactions are carried out in aqueous solutions and water is used as a solvent, all of which utilize the chemical stability of water.
1 9 ． Mixtures
A mixture of two or more substances is called mixture;
( 2 ) A mixture of common special names: ammonia, chlorinated water, aqua regia, natural water, hard water, soft water, hydrochloric acid, concentrated sulfuric acid formalin, water glass; explosion gas, water gas, natural gas, coke oven gas, blast furnace gas, petroleum gas, cracking gas, air; alloy; superphosphate , bleaching powder, black powder, thermite, cement, iron catalyst, glass; coal, petroleum; various fractions of petroleum and petroleum.
[Note] Substances composed of allotropes are mixtures such as red phosphorus and white phosphorus . Substances composed of isotope atoms are pure substances such as H 2 O and D 2 O are mixed into pure substances.
20 ． Elemental
Pure substances composed of the same elements are called simple substances.如 O 2 、 Cl 2 、 N 2 、 Ar 、 金刚石 、铁 (Fe) 等。 HD , 16 O , 18 O are also elemental, and elemental is divided into metal element and non-metal element.
21 ． Compounds
Pure substances composed of different elements are called compounds.
Compounds can be divided into various types from different classification perspectives, such as ionic compounds and covalent compounds; electrolytes and non-electrolytes; inorganic compounds and organic compounds; acids, bases, salts and oxide et al.
22 ． Acid
Ionization Theoretically, the cations from electrolysis are all H + The compound is called acid.
常见强酸： HCIO 4 、 H 2 SO 4 、 HCl 、 HNO 3 …
常见弱酸： H 2 SO 3 、 H 3 PO 4 、 HF 、 HClO 、 H 2 CO 3 、 H 2 SO 3 sp an7span , CH 3 COOH…
23 ． Base
The ionization theory states that,The anions generated when the electrolyte is ionized are all OHˉ The compound is called a base.
常见强碱： NaOH 、 KOH 、 Ba(OH) 2 、Ca(OH) 2 …
常见弱碱： NH 3 ·H 2 O 、 Al(OH) 3 、 Fe(OH) 3 …
24 ． Salt
A compound that generates metal cations ( or NH 4 + + ) when ionized is called a salt.
盐的分类 ： ① 正盐 ：如： (NH 4 ) 2 SO 4 、 Na 2 SO 4 … ② 酸式盐 ：如 NaHCO 3 、 NaH 2 PO 4 、 Na 2 HPO 4 …③ basic salt: Cu 2 (OH) 14 2 3 spans pan7span … ④ 复盐： KAl(SO 4 ) 2 ·12H 2 O…
25 ． The oxide
consists of two elements,One of these compounds is oxygen called oxide .
（1） 氧化物的分类方法按组成分：
金属氧化物： Na 2 O 、 Al 2 O 3 、 Fe 3 O 4 …
非金属氧化物： NO 2 、 CO 、 SO 2 、 CO 2 …
（2） 按性质分：
不成盐氧化物： CO _sp an14span 、 NO
成盐氧化物：酸性氧化物： CO 2 、 SO 2 …
碱性氧化物 ： Na 2 O 2 、 CuO …
两性氧化物： Al 2 O 3 、 ZnO
Peroxide: Na 2 O 2 2 3 _span14 ppan pan superoxide: KO 2
26 ． Allotropes
Different elements formed by the same element are allotropes.
（ 1 ）常见同素异形体：红磷与 白 磷； O 2 与 O 3 ；金刚石with graphite.
( 2 ) Allotropes can be converted into each other, which is a chemical change but not a redox reaction of .
.
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-