What are the chemical properties of metals, acids, and alkalis in junior high school chemistry?

Acid refers to compounds in which all cations produced during ionization are hydrogen ions; Base refers to a compound in which all the anions produced during ionization are hydroxide ions; Salts refer to compounds that form metal cations (or ammonium ions) and acid ions when ionized.

Chemical properties: Acid: The cations produced during ionization are all hydrogen ions, which are only formed by the combination of hydrogen ions, acid ions and non-metallic elements. For example: H2SO4 (sulphuric acid), HCl (hydrochloric acid), HNO3 (nitric acid), H2CO3 (carbonic acid).

Alkali: The anions produced during ionization are all hydroxide ions, which are formed by the combination of metal ions and hydroxide ions. For example.

NaOH (sodium hydroxide), KOH (potassium hydroxide), Ca(OH)2 (calcium hydroxide), NH3·H2O, NH4OH (ammonia).

Salts: Compounds containing metal cations (or NH4 ammonium) and acid ions are formed during ionization, most of which are formed by the combination of metal ions and acid ions. For example: Na2CO3 (sodium carbonate), CuSO4 (copper sulfate).

NH4NO3 (ammonium nitrate).

I won't talk about their physical properties. The chemical properties are as follows:

Metal: the combustion of metal in the air; Substitution reaction with acid; Reacts with certain saline solutions. Sour:

discoloration of the indicator; Neutralization reaction with alkali; Metathesis reaction with salt; displacement reaction with certain metals; Reaction with metal oxides (I don't know if I was exposed to this in junior high school) alkali: discoloration of the indicator; Neutralization reaction with acid; metathesis reaction with salts; Bases can react with non-metallic oxides. Salt:

and acid reactions; reaction with alkalis; and salt displacement reaction....

1. The concept of acid, alkali and salt.

1. Acid: The cations generated during ionization are all compounds of hydrogen ions. Such as: HCl, HNO3, H2SO4, H2CO3, etc.

HCl= H+ +Cl- (monobasic acid); H2SO4 = 2H++SO42- (dibasic acid);

2. Base: The anions generated during ionization are all compounds of hydroxide ions. Such as: NaOH, Ca(OH)2, etc.

NaOH = Na+ +OH- (monobase); Ca(OH)2 = Ca2+ +2OH- (dibasic base);

3. Salt: a compound that generates metal ions (or ammonium ions) and acid ions when ionized. Such as: NaCl, NH4NO3, etc.

nacl = na+ +cl-； nh4no3 = nh4+ +no3-；

2. Common acids.

1. Acids commonly used in life: hydrochloric acid (HCl) contained in gastric juice, sulfuric acid (H2SO4) contained in batteries, sulfuric acid and nitric acid (HNO3) contained in acid rain, acetic acid (CH3COOH) contained in vinegar; Carbonic acid, citric acid, etc., which may be contained in beverages.

2. Universality of acid: the acid solution reacts with the acid-base indicator, the purple litmus test solution turns red when it encounters the acid solution, and the colorless phenolphthalein reagent does not change color when it encounters the acid solution; Acid + Metal = Salt + Hydrogen (Displacement Reaction); Acid + Metal Oxide = Salt + Water; Acid + Base = Salt + Water; Acid + salt = new acid + new salt.

2. Several important salts.

1. Classification of salts: classification is carried out according to the types of cations and acid groups that make up the salts. According to the different cations, salts can be divided into sodium salts, potassium salts, magnesium salts, iron salts, ammonium salts, etc.

sodium chloride is a sodium salt); Depending on the acid radical, salts can be divided into sulfates, carbonates, nitrates, hydrochlorides, etc. (Sodium chloride is hydrochloride).

3. Common alkali: caustic soda is highly corrosive, and calcium hydroxide and ammonia are also corrosive. Acting with the acid-base indicator, the purple litmus reagent turns blue when it encounters the alkali solution; Colorless phenolphthalein turns red when it encounters an alkaline solution.

Sodium carbonate, sodium sulfate and the like.

The distinction of acid and alkali salts in junior high school should first be based on the definition:

Acid: The cations ionized in the solution are all H+ substances, such as HCl, HNO3, H2SO4, etc.;

Alkali: The anions ionized in the solution are all OH-, such as NaOH, KOH, CA(OH)2, etc.;

Salt: a substance composed of metal cations (or ammonium ions) and acid groups, such as NaCl, Kno3, Cu(NO3)2, Baso4, etc.

The distinction of acid and alkali salts can be distinguished according to the general properties of acid and alkali salts, and the obvious phenomenon that usually occurs during the reaction is precipitation and gas generation, and it is necessary to keep in mind the common ion pairs in the problem of non-coexistence.

Pro, acids, bases, and salts are basic concepts in chemistry, and they are very different in their properties and uses. Here's how to distinguish between acids, bases, and salts:

Characteristics of acid: sour taste, blue litmus paper turns red, neutralization with alkali to form salt and water, reaction with metal to form hydrogen.

Characteristics of alkali: bitter taste, red litmus paper turns blue, neutralizes with acid to form salt and water, reacts with grease to form soap.

Characteristics of salt: tasteless, colorless or white, soluble in water, reaction with acid or alkali to form salt and water, can be used for table salt, fertilizer, fertilizer, etc.

With the above characteristics, acids, bases, and salts can be easily distinguished.

1.Reaction of metals with oxygen.

Reactive metals such as aluminum, magnesium, etc., can react with oxygen at room temperature to form oxide protective films.

Iron and copper hardly react with oxygen at room temperature, but can react with oxygen at high temperature or when ignited.

Gold does not react with oxygen even at high temperatures and is chemically very stable.

Note: The reactivity of a metal can be roughly judged based on how easily it reacts with oxygen.

2.The metal reacts with the acid.

Reactive metals can undergo displacement reactions with acids to form salts and hydrogen, for example.

z n+h:s o：= z n s o.+h: 。

Note: Not all acids can be displaced-with metals to form salts and hydrogen. Acids generally refer to dilute sulfuric acid and dilute hydrochloric acid, rather than acids such as concentrated sulfuric acid and nitric acid;

Metals refer to reactive metals, which are listed before hydrogen in the order of metal activity, but generally do not consider the most reactive k, c a, and n a.

3.Metals react with solutions of certain compounds.

Reactive metals can undergo a displacement reaction with a solution of certain compounds, displacing them out of the solution. For example, iron can react with a solution of copper sulphate to form copper and ferrous sulphate.

II. 1 Meaning.

The reaction between one element and one compound to produce another element and compound is called a displacement reaction.

2.Features. The displacement reaction is a basic type of reaction that is classified by the category of reactant products. It is characterized by; The reactant and the product must be both an elemental substance and a compound.

In junior high school, I talked about metals a lot, that is, aluminum and iron, and the most suitable properties for them are the most different.

First, there are 5 properties of acids.

1.Acids act with acid-base indicators.

2.Acid and active metal finger substitution reaction (metal in the metal change activity before h) 3Acids react with metal oxides.

4.The acid undergoes a neutralization reaction with the base.

5.The acid reacts with certain salts.

Second, there are four properties of alkali.

1.Acts with acid-base indicators.

2.Acid-base neutralization reaction.

3.Reacts with certain non-metallic oxides.

4.Reacts with certain salts.

Third, there are four properties of salt.

1.Salt and metal displacement reaction.

2.Reaction of salts with acids.

3.Reaction of salt with alkali nucleus.

4.Reaction of salt to salt.

Fourth, there are three chemical properties of metals.

1.Reaction of metals with oxygen.

2.Displacement reaction of active metals with acids.

3.Reaction of metals with salts.

You can write the relevant equations yourself!

Hello!!

The correct one is a, calcium oxide reacts with water to form calcium hydroxide, and calcium hydroxide reacts with carbon dioxide to form calcium carbonate. The mouth of the bottle in B does not produce white smoke, but white mist.

Hcl, dilute H2SO4, CH3COOH, NaOH Ca(OH)2

Salts: various sodium salts, calcium salts, ammonium salts, some potassium salts, kcl, kclo3, kmno4, k2mno4

A part of the aluminum salt, Alcl3, kal(SO4)2, a hectare, destroys part of the iron salt, copper salt, FeCl3, FeCl2, CuCl2, iron sulfate, ferrous iron, copper, etc.

That's probably all that's left.