What are the rules of writing chemical equations for neutralization reactions?

The essence of the neutralization reaction is that H+ and OH- combine to form water (HO). Acid + alkali Salt + water There is a reaction of salt and water formation, not necessarily a neutralization reaction such as:

2Naoh+Co = NaCo+HO) So as long as the acid-base reaction occurs, it is called neutralization, no matter how far it is carried out. The criterion for judging whether the acid and base are completely neutralized is whether the acid and base are exactly completely reacting.

NaOH+HCl==NaCl+Ho Sodium hydroxide can be neutralized with hydrochloric acid to generate sodium chloride and water, and the reaction is exothermic.

Ca(OH) +2HCl==CaCl +2HO Calcium hydroxide can be neutralized with hydrochloric acid to generate calcium chloride and water, and the reaction is exothermic.

Ba(OH) +2HCl==BACL +2HO Barium hydroxide and hydrochloric acid are neutralized to form barium chloride and water.

Fe(OH) +3HCl==FeCl +3HO Iron hydroxide(Fe(OH)) is insoluble in water, but can also neutralize with hydrochloric acid to form ferric chloride and water.

koh+hi==ki+h o Potassium hydroxide and hydroiodic acid undergo a neutralization reaction to produce potassium iodide and water.

Cu(OH) +H SO ==CuSO+2H O Copper hydroxide and sulfuric acid undergo a neutralization reaction to form copper sulfate and water.

The ionic equation oh h h o.

The process of writing the ion equation:

1. Write the equation first: BA(OH) +2HCl=BACL +2HO.

2. Then disassemble: BA +2OH +2H +2Cl =BA +2Cl +2HO.

3. Remove the same ions on both sides: 2oh +2h = 2h o.

4. Divide both sides by 2 at the same time: oh + h = h o.

Error-prone analysis. All oxides and peroxides should be written with chemical formulas, and it must be clear here that active metal oxides or peroxides such as sodium peroxide and sodium oxide are soluble electrolytes but cannot be separated.

There are also strong soluble electrolytes like sodium bicarbonate, but sometimes (e.g. carbon dioxide into saturated sodium carbonate) is also written as a chemical formula, depending on whether it is mainly in the form of a solid substance or in the form of ions in solution.

Acid salts of strong acids, such as sodium bisulfate, should be divided into sodium ions, hydrogen ions and sulfate ions (only bisulfate belongs to this category in high schools); Weakly acid acid salts such as sodium bicarbonate are split into sodium ions and bicarbonate ions (acid salts such as carbonic acid, phosphoric acid, and sulfurous acid belong to this category).

Weak electrolytes, non-electrolytes, oxides, elemental matter, precipitation, and gases cannot be disassembled.

1.Iron reacts with oxygen to form ferric oxide (or iron oxide) 4Fe+3O2=2Fe2O3 2Lead reacts with oxygen to form lead oxide 2pb+o2=(=ignition)2pbo 3

Magnesium reacts with oxygen to form magnesium oxide 2mg+o2=(=ignition)2mgo 4Sodium hydroxide reacts with copper sulfate to form sodium sulfate and copper hydroxide 2NaOH+CuSO4=Na2SO4+Cu(OH)2 5Sodium hydroxide reacts with ferric chloride to form sodium chloride and hydroxide slip pin iron 3NaOH+FeCl3=3NaCl+Fe(OH)3 6

Hydrogen peroxide reacts with oxygen to form oxygen and water 2H2O2=(=MnO2)2H2O+O2 7Potassium chlorate reacts under the conditions of manganese dioxide catalysis and heating to produce potassium chloride and oxygen 2kclo3=(=write mno2 above and write below )2kcl+3o2 8Potassium permanganate reacts under heating conditions to produce potassium manganate, manganese oxide and oxygen 2kmNO4=(=written above)K2mNO4+MNO2+O2 9

Second, let Kai carbon oxide react with clarified lime water to form CO2 + Ca(OH)2=CaCO3 +H2O

Tips for Writing Chemical Equations:

For example, to write the chemical equation for the reaction of carbon with iron oxide at high temperatures, the steps are as follows:

Based on the fact of the reaction (which produces iron and carbon dioxide gas), write the chemical formula of the reactant on the left side of the equation and the chemical formula of the product on the right side of the equation. If there is more than one reactant or product, they are connected with a plus sign respectively (the "+" sign between the reactants indicates "with reaction", and the "+" sign between the products means "with" and a ** paragraph is drawn between the left and right of the formula). In this step, you must pay attention to writing the chemical formulas of various substances correctly, otherwise, the written formulas are meaningless!

c+fe2o3──fe+co2

According to the law of conservation of mass, the number of atoms of the same element on the left and right sides is equal (i.e., trim) by the method of matching coefficients, and then the ** segment is changed to an equal sign (the equal sign indicates that "generated" It should be noted that the matching time can only select the appropriate coefficient, and cannot change the chemical formula.

3c+2fe2o3=4fe+3co2

Indicate the reaction conditions, such as ignition, energizing, high temperature, heating (denoted by a " sign), catalyst, etc., on the equal sign or arrow sign, and indicate the state of the gas or precipitate product in the product. The product is a gas, and the right side of its chemical formula is marked with a " " sign (if there is a gas in the reactant, the gaseous product is no longer marked with the " " symbol); The product is precipitated with the addition of the "" sign.

3c+2fe2o34fe+3co2↑

In short, when writing chemical equations, they must conform to the objective laws of chemical reactions and cannot be fabricated out of thin air. The writing procedure is generally as follows: write the chemical formula - the coefficient should be balanced - the middle and equal signs - the conditions should be noted - the gas or precipitation should be generated, which should be marked with the arrow number.

To write chemical equations well, it is also necessary to master and use the solubility table of acids, bases, and salts, the order of metal activity and the valency of common elements and atomic groups, as well as the skills of writing chemical formulas of substances.

1.The metathesis reaction can only be swapped (the three conditions of the metathesis reaction must be met), such as the reaction between salt and acid, and the reaction between acid and base.

2. For redox reactions.

Remember the strength of oxidative reduction, and the neutralization reaction is the valence to the middle.

The disproportionation reaction is valency to both sides.

1. Principles for writing chemical equations.

Based on objective facts. Observe the law of conservation of mass.

2. Write the order of chemical equations.

Reactants" "Reaction conditions" "Product" or "Trim" "Changed to ".

Common reaction conditions: ignition, heating ( ) high temperature, catalyst, etc.

"Scope of use: No gas in the reactant to participate in the reaction, if there is gas in the product, note to the right of the chemical formula of the gaseous substance" "Reaction in solution without the participation of solids, if there is a solid in the product, note to the right of the chemical formula of the solid substance".

Ordinary chemical reaction equations need to be noted: when there is no gas in the reactant, the product should remember to mark the gas symbol (the same goes for the precipitation symbol).

The ionic equation should be noted that non-electrolytes and weak electrolytes cannot be disassembled.

The equation of thermochemical reaction should be noted that each substance should be written with the state (such as: s, l, aq, g) In general, it is not necessary to write the condition (except for the case of 25 and 101kpa, which is specially pointed out) Note that the positive and negative signs of h should be marked (+, all of them!). ）

Chemical Reaction Equations

A chemical equation, also known as a chemical reaction equation, is a formula that uses a chemical formula to represent a chemical reaction. Chemical equations reflect objective facts. The formula that uses the chemical formula (organic matter in organic chemistry generally uses the simple structure formula) to express the chemical reaction of a substance is called a chemical equation.

The chemical equation not only indicates the reactants, products, and reaction conditions. At the same time, the stoichiometric number represents the quantitative relationship between the reactants and the product substances, and the mass relationship between the substances can also be expressed through the relative molecular mass or relative atomic mass, that is, the mass ratio between the substances. For gas reactants and products, the volume ratio can also be obtained directly from the stoichiometric number.

It is very simple, you need to look at the valency in the chemical reaction, if it is a replacement reaction, the valency is unchanged, for the decomposition reaction or the chemical reaction to see the change of valency, the valency of the metathesis reaction is also unchanged, the valency formula: monovalent hydrochloride, sodium chloride, potassium, silver, divalent oxygen, calcium barium, magnesium, zinc, trialuminum, tetrasilicon, pentavalent phosphorus, 23 iron, 24 carbon, 12345 is nitrogen, elemental zero price do not forget. Then immediately after the trimming, the total valence in the compound is 0, which is balanced according to the law of conservation of mass.

Write down the reactants and products, find the proportion of each element in it, multiply the less by the proportion, look at the number of atoms of the elements on both sides of the equal sign, and then match.

Remember to take a look, two with (trim), three verification of the strategy, quickly find the relationship...

If it is redox, the product should be introduced first, and then the conservation of charge, the conservation of mass, and the balance of mass should be reduced according to the valence; Ordinary observation is sufficient!

Conservation of mass, factual basis, periodic table, it's as simple as that.

How to Write Chemical Equations.