I d like to ask how the chemical formulas, such as 2 and 4 in H2SO4, are formulated

The outermost shell of S (sulfur) has six electrons, O (oxygen) is in the same group as S, and the outermost shell also has six electrons, S and 4 O form a shared electron pair, reaching a stable state, and the whole is -2 valence, while H has only one electron to form an ion manifestation +1 valence, so two Hs are required. The above is the origin of 2 and 4, and there are still shortcomings, please understand.

Chemical formulas are written by the outermost electrons of the element. H2SO4 is a covalent compound with S atom as the center, S outermost six electrons, each combined with four oxygen, two of which are coordination bonds, two oxygen atoms and two H atoms share an electron pair.

If it's junior high school, there's no need to understand these things, just be familiar with them and use them

Friend, this thing has nothing to do with valency, this is a fixed composition of a molecule, which is equivalent to a person with two legs and a head. Don't bother, and the valency is determined by the molecular makeup, hopefully.

For example, H2SO4 and S atoms adopt sp3 hybrid orbitals to form two covalent bonds with two oxygen atoms of the four oxygen atoms, and the other two oxygen atoms accept the electron pairs of sulfur atoms to form a covalent match respectively, and the hydrogen atom is attached to the oxygen atom.

Chemical valence, in general compounds, h is +1 valence, s is +6 valence, and o is -2 valence.

s is +6 valence h is +1 valence o is - 2 valence and the final result is 0, so there are two h plus one s and 4 o, and the final result is 0

H2SO4 is sulfuric acid.

Sulfuric acid, with the molecular formula H2SO4, is a colorless and odorless oily liquid, a strong acid with a high boiling point and difficult to volatile, soluble in water, and miscible with water in any ratio.

Sulfuric acid is one of the most reactive binary inorganic acids that reacts with many metals. High concentration of sulfuric acid has strong water absorption, can be used as a dehydrating agent, carbonized wood, paper, cotton and linen fabrics and biological skin and other carbohydrate-containing substances. When mixed with water, a large amount of heat energy is also emitted.

Uses:

1. In the metallurgical and petroleum industry, sulfuric acid is used in the production process of non-ferrous metals to dissolve and remove other metals that are inclusional, and sulfuric acid is used to remove sulfur-containing compounds and unsaturated hydrocarbons in the petroleum industry.

2. In the textile and printing and dyeing industry, the role of sulfuric acid is also very important, in the textile industry for the production of chemical fibers is viscose silk, which needs to be mixed with sulfuric acid and other solutions as a solidification bath of viscose silk, and there is almost no need for sulfuric acid in the preparation of dyes in the dye industry.

3. In the pharmaceutical industry, sulfuric acid is used for sulfonation reaction in the preparation of sulfonamide drugs, and nitrification reaction in the preparation of the strong fungicide nitrofuracillin.

4. In agriculture, sulfuric acid can be used for soil improvement and fertilizer production. For example, sulfuric acid is used to improve the calcareous soil with a very high pH value, and the pH value of the lake water is changed.

The above content reference: Encyclopedia - Sulfuric Acid.

Be cautious and look at the atomic group.

SO4, one on the left and 3 on the right. The left H2SO4 is filled with 3, and the left H becomes 6 wide trap wheels. Add 3 before the line of the draft gauge on the right

H2SO4 is the chemical name for sulfuric acid.

Sulfuric acid is one of the more active binary inorganic strong acids, which can react with most metals. High concentrations of sulfuric acid are highly absorbent and can be used for some carbohydrate-containing substances such as dehydrating agents, carbonized wood, paper, cotton and linen fabrics, and biological skin and meat.

H2SO4 Physical Properties:

Pure sulfuric acid is usually a colorless, oily liquid with a density of g cm and a boiling point of 337 that can be separated from water in any proportion and can release a large amount of heat to boil the water.

When heated to 290, it begins to release sulfur trioxide, which eventually becomes an aqueous solution of chelating acid, which boils at 317 to become a complete azeotropic mixture. The high boiling point and relatively high viscosity of sulfuric acid is due to the strong hydrogen bonds within its molecules. Due to its large dielectric constant, sulfuric acid is a good solvent for electrolytes but not for non-electrolytes.

The melting point of sulfuric acid is that the freezing point can be reduced by adding water or sulfur trioxide.

First aid measures. Sulfuric acid contact with ** needs to be rinsed with a large amount of water, and then coated with 3% 5% sodium bicarbonate solution, and quickly seek medical attention.

Immediately after splashing into the eye, the eyelid should be lifted and rinsed thoroughly with plenty of running water or saline for at least 15 minutes. Seek medical attention promptly.

After inhaling the vapor, it should be quickly removed from the scene to a place of fresh air. Keep your airways open. If you have difficulty breathing, give oxygen.

If breathing stops, artificial respiration is performed immediately. Seek medical attention promptly. After ingestion, rinse the mouth with water, give milk or egg whites, and seek medical attention quickly.

Hello, the two chemical equations before and after are both ionization equations for sulfuric acid, but the application scenarios are different.

Sulfuric acid is diluted with a large amount of water and ionized, generally the first-order reaction Hso = H + Hso is completely ionized, and the second reaction Hso H + So is incomplete ionization.

According to the acidity coefficient of sulfuric acid pka1=, pka2=, its secondary ionization is not sufficient, the primary ionization of sulfuric acid of 1mol L is complete, and the secondary ionization is about 10%, that is, there is still a large amount of HSO in the solution. Even with Nahso solution, the bisulfate is only about 30% ionized.

When sulfuric acid is dissolved in a small amount of water, on the one hand, the sulfuric acid molecules diffuse in the water, and in this physical process, a certain amount of heat is absorbed (the first ionization reaction described in the inscription); On the other hand, a chemical process takes place, that is, there is a strong ability to combine sulfuric acid molecules with water molecules to produce hydronium ions (the second equation is inscribed).

h₂so₄+h₂o= h₃o⁺+hso₄⁻

hso₄⁻+h₂o = h₃o⁺+so₄²⁻

h₂so₄+2h₂o =2h₄o⁺+so₂²⁻

The following is quoted from the encyclopedia of "Concentrated Sulfuric Acid Ionization".

Sulfuric acid and water form fairly stable hydrates, such as H2SO4·H2O, H2SO4·2H2O, H2SO4·4H2O, etc. (these hydrates can be precipitated from the solution in crystalline form at low temperatures). Since a large amount of heat is released when hydronium ions and various hydrates are formed (1mol of sulfuric acid is mixed with excess water at 20°C, the heat of dissolution is kj), and more heat is released than it is absorbed, so a large amount of heat is released when concentrated sulfuric acid is diluted.

Strictly speaking, it is the latter that is correct.

Because most of the ions in water are in the form of hydrated ions.

The former is a process in which water involvement is omitted.

There is a difference between H3O++Hso4- and

The former has been dissociated into free hydrogen ions and bisulfate ions, and the latter is a sulfuric acid molecule tightly bound to water molecules, much like solid crystalline water.

5h2s+2kmno4+3h2so4==5s+2mnso4+k2so4+8h2o

First of all, to analyze this chemical formula, potassium sulfate should be clarified first.

and sulfate in manganese sulfate nuclear return mold retardation.

From sulfuric acid, so the s valency in sulfate.

No change. It is hydrogen sulfide that has undergone valency changes.

S and potassium permanganate.

manganese. s rises from -2 to 0 and rises by 2

MN reduced from +7 to +2 by 5

According to the conservation of electrons, the number of lost electrons is equal to the number of e-books.

So write 5 in front of h2s and 2 in kmno4

Then write 5 in front of S, write 2 in front of MnSO4, K element is in equilibrium, and then write 8 in front of H2SO4, and test it with the number of hydrogen. Equation balance.

The general order of electron conservation trim is to look at the elements with varying valency first, then metals, then acid roots, and then oxygen, which is tested with hydrogen (hydrogen can also be used first and then oxygen).

Sometimes there may be a fraction after matching, just expand all the numbers to whole numbers.

If the elements of the price increase and fall are not unique, the same method is to classify the rising ones and the falling ones into one category.

If an element rises and falls, you can start from the right side of the equation.

The key is to take a few more equations to practice, and you will be familiar with a few problems immediately.

Trimmed: 2FeSO4 + H2SO4 + 2HNO3 (concentrated) ==Fe2 (SO4) 3 + 2NO2 + 2H2O

Two molecules (or moles) of ferrous sulfate and one molecule (or molars of local hail) of thithotonnafaic acid reacts with two molecules (or moles) of nitric acid to form one molecule (or moles) of ferric sulfate and two molecules (or moles) of nitrogen dioxide and two molecules (or moles) of water.