Junior 3 Chemistry Ask questions about the calculation of the valency of elements in organic matter

In organic matter, the positive and negative valence of the valence is generally not discussed, only the amount of covalent is discussed. In organic matter, C is 4-valent, H is 1-valent, and O is 2-valent. If we have to explain positive and negative, in the junior high school stage, we can calculate the organic structure according to the method of determining the valency of elements in inorganic chemistry, and generally consider that O is -2 valence, H is +1 valence, C is positive when combined with O, negative valence when combined with H, and 0 valence between C and C.

Each covalent bond is a single valence, a single bond is a monovalent, a double bond is a bivalent, and so on. For example, the structure of C2H4O2 can be written as CH3-COOH. The previous carbon connects 3 C-H bonds and one C-C bond, and its valency can be calculated as:

3 (bound to H) + 0 (bound to C) = - 3, the latter C has a C-C bond, a C=O and a C-O bond, then the valency of this carbon is: 0 + (2) + (1) = + 3.

Therefore, in order to calculate the valency in organic matter, it is necessary to clarify the structure of the organic matter.

Please note that when it comes to organic chemistry, we don't talk about valencies! Because we mainly study their structural characteristics (usually covalent bonds and the like), we ignore this. As for the question you raised, it's normal for it to appear.

h doesn't have to be +1 price.

h has a valence of -1, +1. Oxidan may also be a fraction.

o also has -1, -2 equivalence states.

Look at it according to the internal structure.

According to the situational analysis: h does not have to be +1 valence.

h has a valence of -1, +1. Oxidan may also be a fraction.

o also has -1, -2 equivalence states.

C2H4O2 is part of organic chemistry and cannot be understood by inorganic chemistry, just as we learn about rational numbers, but we cannot use the concept of rational numbers to study irrational numbers (e.g., find what is the square root of a negative number, etc.).

Organic matter does not discuss valence, only inorganic matter is discussed!

The valency of organic matter is mostly determined by covalent bonds, h must be +1 valence, o must be -2 valence. By the time you get to high school, you'll get to the bottom of it. I'll give you a rough idea first.

For example, FeO2 is arranged in a straight line by a 2-valent iron atom and 2 oxygen atoms, and SiO2 is a space cube structure formed by the covalent bond of silicon atoms and oxygen atoms.

Let's study it again in high school.

The upstairs is basically correct.

In the study of chemistry in junior high school, valency is a must-learn knowledge point, so how to calculate valency? The following is a summary of "How to calculate the rolling valence of junior high school chemical elementalization", which is for reference only, and you are welcome to read this article.

Valency calculation

The price of the elemental chemical cavity jujube is 0. The algebraic sum of the valency of a compound is 0, which is to remember the valency of common substances and deduce the valency of other elements. For example, hydrogen is commonly +1, oxygen-2, metals are generally +1 or +2 valence, iron has +2, +3, and some common valence states of acid ions, such as -2 of sulfate ions, -1 of hydroxide ions, -1 of nitrate ions, and -2 of carbonate ions.

First, the valency of some elements with only one valence is marked, and then the most commonly used valency of a certain element, such as oxygen, whose compound can be negative divalent or negative monovalent (oxygen is negative in peroxide), and finally according to the principle of algebra sum of positive and negative valency algebra to zero (note: to bring in the corner mark to calculate), determine the valency of unknown elements or elements with more valence.

Knowledge points of valence 1, valence has positive and negative valence.

2. Oxygen is usually -2 valence.

3. Hydrogen usually shows +1 valence.

4. When metallic elements and non-metallic elements are combined, metallic elements show positive valence, and non-metallic elements show negative valence (generally speaking, the positive valence is written in the front, and the negative valence is written in the back).

5. Some elements can show different valencies in the same substance.

6. The algebraic sum of positive and negative valencies in the compound is 0.

7. The valency of an element is a property exhibited by the atoms of an element when forming a compound, therefore, in an elemental molecule, the valency of an element is 0.

Further reading: Middle School Chemistry Learning Methods

Review often and memorize more

After class, you should review in time and do your homework carefully, which is an important part of learning chemistry well. Revision can be done after class, after week, unit, chapter, and comprehensive. Methods of revision include retelling, dictation, and making connections.

Knowledge can only be firmly grasped through multiple revisions. There are many basic concepts and principles in the current junior high school chemistry textbooks, and there are more than 20 element symbols that require mastery, and there are many more. Chemical formulas and chemical equations and some other knowledge.

Most of these contents need to be memorized on the basis of understanding, and most of them are the basis for learning chemistry, and if you can't memorize them, you will find it difficult to walk in the "kingdom of chemistry".

Do experiments

Junior high school chemistry is a natural science based on experiments, and experiments are an important way and means to carry out scientific activities. In daily learning, we should not only be familiar with the experimental principles and experimental methods of each experiment, but also pay attention to the experience of the experimental process, know the scientific methods contained in the experiment, understand the areas that need to be improved in the experiment, and pay special attention to the use of substances and phenomena around the chemical experiment. In this way, we can develop chemical concepts and enrich scientific literacy in experimental learning and activities.

The valency of organic compounds is calculated according to the principle of positive 1 valence of hydrogen, negative 2 valence of oxygen, negative 3 valence of nitrogen, and the algebraic sum of 0.

Related explanation: Organic compounds in a narrow sense are mainly composed of carbon and hydrogen, which are certain carbon-containing compounds, but do not include carbon oxides, carbonic acid, carbonates, cyanides, thiocyanides, cyanates, metal carbides, and some simple carbon-containing compounds. However, generalized organic compounds can be carbon-free, organic matter is the material basis of the cavity state produced by the source of life, and all living organisms contain organic compounds.

Such as fats, amino acids, proteins, sugars, heme, chlorophyll, enzymes, hormones, etc.

In the alternate bond compound, the algebraic sum of the valencies of each element is 0.

Na2FPO3, known F is -1 valence, Na is +1 valence, O is -2 valence, phosphorus valency = +2-1 + x + (-2 * 3) = 0, x = +5

According to the chemical formula, the valence du is obtained

Basis: Algebra of positive and negative valencies in compounds.

zhi and for the DAO zero.

Methods: (1) Chemistry.

When the formula is known, the valency of one of the elements is determined. This can be based on the valence table of common elements, or based on what is known.

Example 1: Knowing that hydrogen is +1 valence and oxygen is -2 valence, try to determine the valency of sulfur in sulfuric acid (H2SO4).

Let the valency of sulfur in sulfuric acid be x

1×2 + x +(2)×4 = 0

x=+6A: The valency of the sulfur element in sulfuric acid is +6

Example 2: Calcium is known to be +2 valence, try to find that Ca(OH)2 is the valency of hydroxide.

Let the valency of hydroxide be x

then 2 + 2x = 0

x = 1A: The valency of hydroxide in Ca(OH)2 is 1

Example 3: Knowing that the valency of carbonate (CO3) is -2, try to determine the valency of carbon in carbonate.

The algebraic sum of positive and negative valencies in an atomic cluster is equal to the valency of the atomic cluster. Let the valency of the carbon element be x

then x + 2) 3 = 2

x = +4

Answer: The valency of the carbon element in carbonate is +4

The junior high school textbook says it very clearly.

1. The valency of the element is specified as 0

2. The algebraic sum of the valency of all elements in the compound is 0

3. Hydrogen in compounds generally exhibits +1 valence, and oxygen generally exhibits -2 valence.

4. Commonly used valencies can be memorized through formulas.

In a compound, the valency of only one element is unknown and may be found by the rule of 2.

According to the algebraic sum of the positive and negative valency of each element in the molecular formula of the compound, equal to zero, the valency of each element in the chemical formula is obtained.

For example, in H2SO4, hydrogen is positive 1 valence, oxygen is negative 2 valence, and sulfur is positive 6 valence.

First of all, the elements in the chemical formula are written in the order of positive valence first and negative valence last; Secondly, the valency of each element is marked above the element; Again, cross-write the valency value to the lower right corner of the corresponding element; Finally, the reduction of differentiation is carried out, and the algebraic sum of valence is used to check the calculation.

For example, if the valency of P is known to be +5 and the valency of O is -2, find the chemical formula of the compound formed by P and O.

1. Write the elements before and after the positive: p o

2. Accurately mark the valence: +5 -2

p o3, cross write to the bottom of the right corner: p2o5

4. Approximate differentiation to test: it is the simplest; Test: (+5) 2+(-2) 5=0, written correctly.

That is, the chemical formula is P2O5