Chemical formula

use Element symbols And the figures of material Form . The chemical formula is Experimental type , Molecular formula , Structure type , Show type , Electronic type Collectively.
Chemical formula

Chemical formula Basic definitions

Represented by symbols pure substance Composition and atom The number of equations is called chemical formula.
pure substance There are some components are available, a corresponding formula for its composition (each consisting of pure substance is fixed, so that the chemical formula of each substance consisting of only one). Some chemical also said such molecules, the chemical formula is called molecular formula. The chemical formula represents only pure substance, mixture No chemical formula.
[key] interpretation of chemical formula significance
classification Significance Examples (H Two O for example)
Macroscopic
The representation of a substance
water
The representation of the material elements.
Water is composed of two elements of hydrogen and oxygen
Microcosmic
The representation of a molecule
A water molecule
The said material molecules
Each water molecule has two hydrogen atoms and one oxygen atom.

Macroscopic
The representation of a substance
water
The representation of the material elements.
Water is composed of two elements of hydrogen and oxygen
Microcosmic
The representation of a molecule
A water molecule
The said material molecules
Each water molecule has two hydrogen atoms and one oxygen atom.
Describe the molecular structure, specific to a substance molecule, say, a molecule is made up of a few each atom A. Emphasize a molecule!
use Chemical symbol The chemical element in the compound called atomic ratio Experimental type Such as, acetylene And benzene are Hydrocarbon And their composition are 92.3% carbon, 7.7% hydrogen, carbon and hydrogen atom ratio is 1: 1, derived from acetylene and benzene The type is CH. Some inorganic compounds (such as sodium chloride) by Ionic crystal The composition, crystal internal cations and anions arranged alternately. But, Sodium chloride crystal is the number of sodium ions and chloride ions has not solved the problem Just know, Na: Cl=1: 1, we can only use NaCl representative experiment sodium chloride . Chemical symbol consisting of chemical molecules known as molecular type, its meaning is: the composition of the compound elements; elements Atomic number The ratio of weight; and atoms of elements. Use chemical symbols and valence bond between atoms in each said compounds Chemical structure The way is called Structure type And it points out that the molecular arrangement of the atoms in the sequence and connection mode, organic compound The commonly used structure type, it can eliminate the Isomerism The disadvantages of different compounds with the same molecular formula represents caused. for example Butane and Isobutane The molecular formula is C Four H Ten However, different structure type
Thus, the structure clearly distinguish the n-butane and i-butane. Marked between each atomic compound order simplified structure called Show type As shown, the ethanol is C of type Two H Five OH.
The sum of the atomic weight of the atoms in the formula, the amount of chemical called type. (by the molecular composition of the material is also called molecular weight)

Chemical formula Common examples

Chemical formula Elemental

Non metal Elemental
hydrogen
carbon
phosphorus
sulfur
H Two
C
N Two
O Two
P
S
Cl Two

hydrogen
carbon
nitrogen
oxygen
phosphorus
sulfur
Chlorine
H Two
C
N Two
O Two
P
S
Cl Two
Metal element
sodium
magnesium
potassium
calcium
zinc
copper
barium
tungsten
mercury
Na
Mg
Al
K
Ca
Fe
Zn
Cu
Ba
W
Hg

sodium
magnesium
aluminum
potassium
calcium
iron
zinc
copper
barium
tungsten
mercury
Na
Mg
Al
K
Ca
Fe
Zn
Cu
Ba
W
Hg

Chemical formula Chemical compound

The common element valence memory formula:
Potassium sodium hydrogen is monovalent silver
The price is two barium calcium magnesium zinc
Fluorine chlorine bromine iodine negative valence
Usually two negative oxygen sulfur price
There are two Lv Zhengsan copper
It is three two of ferrous iron
Valence, remember
Don't forget the elemental is zero
Common memory cluster valence formula:
A negative hydrogen nitrate
Two negative sulfate carbonate
Is the price is ammonium

  

Common atoms:
Is the price: Ammonium (NH Four ).
Negative valence: Oh (OH ), MnO (MnO Four ), Nitrate (NO Three ), Hyperchlorite (ClO Three (HCO), bicarbonate Three (CH3COO), acetic acid ).
Two negative charges: Carbonate (CO Three ), Sulfate (SO Four The root (MnO), manganese oxide ), Sulfite (SO Three ).
Negative valence: Phosphate (PO Four ).
Common oxides
Carbon monoxide
Carbon dioxide
H Two O
CO
CO Two
P Two O Five
Na Two O
NO Two
SiO Two
sulfur dioxide
SO Two
SO Three
NO
MgO
CuO
BaO
Cu Two O
   
FeO
Fe Two O Three
Fe Three O Four
Al Two O Three
WO Three
   
       
Ag Two O
PbO
MnO Two
       

water
Carbon monoxide
Carbon dioxide
Phosphorus pentoxide
Sodium oxide
Nitrogen dioxide
Silicon dioxide
H Two O
CO
CO Two
P Two O Five
Na Two O
NO Two
SiO Two
sulfur dioxide
Three t
nitric oxide
magnesium oxide
Copper oxide
Barium oxide
Cuprous oxide
SO Two
SO Three
NO
MgO
CuO
BaO
Cu Two O
Ferrooxidans
Ferric oxide
Fe3O4
alumina
Tungsten trioxide
FeO
Fe Two O Three
Fe Three O Four
Al Two O Three
WO Three
Silver
Lead
manganese dioxide
Ag Two O
PbO
MnO Two
Chloride / hydrochloride
potassium chloride Magnesium chloride calcium chloride Copper chloride zinc chloride Barium chloride Aluminium chloride
KCl NaCl MgCl Two CaCl Two CuCl Two ZnCl Two BaCl Two AlCl Three
Ferrous chloride Ferric chloride Silver chloride          
FeCl Two FeCl Three AgCl          

sodium chloride (salt)
Common acid
sulphuric acid
hydrochloric acid
phosphoric acid
H Two SO Four
HCl
HNO Three
H Three PO Four
H Two S
HBr
H Two CO Three
H Two SO Three
H Three BO Three HIO Three H Two MnO Three HOCN

sulphuric acid
hydrochloric acid
nitric acid
phosphoric acid
Hydrogen sulfide
Hydrogen bromide
carbonic acid
Sulfite
boric acid
Iodate
Manganate
Cyanate
H Two SO Four
HCl
HNO Three
H Three PO Four
H Two S
HBr
H Two CO Three
H Two SO Three
Common salt
CuSO Four
BaSO Four
CaSO Four
K Two SO Four
MgSO Four
FeSO Four
Fe Two (SO Four ) Three
NaHSO Four
KHSO Four
Na Two SO Three
NaNO Three
KNO Three
AgNO Three
Cu (NO Three ) Two
Ca (NO Three ) Two
NaNO Two
Na Two CO Three
CaCO Three
MgCO Three
           
K Two CO Three
           

Copper sulphate
barium sulfate
calcium sulfate
Potassium sulphate
Magnesium sulphate
ferrous sulfate
ferric sulfate
CuSO Four
BaSO Four
CaSO Four
K Two SO Four
MgSO Four
FeSO Four
Fe Two (SO Four ) Three
aluminum sulfate
Sodium bisulfate
KHSO4
sodium sulfite
Sodium nitrate
potassium nitrate
silver nitrate
Al Two (SO Four ) Three
NaHSO Four
KHSO Four
Na Two SO Three
NaNO Three
KNO Three
AgNO Three
Magnesium nitrate
Cupric nitrate
Calcium nitrate
Sodium nitrite
sodium carbonate
Calcium carbonate
Magnesium carbonate
Mg (NO Three ) Two
Cu (NO Three ) Two
Ca (NO Three ) Two
NaNO Two
Na Two CO Three
CaCO Three
MgCO Three
potassium carbonate
K Two CO Three
Common base
sodium hydroxide
NaOH
Ca (OH) Two
Ba (OH) Two
Cu (OH) Two
KOH
sodium sulfide        
Fe (OH) Two
Na Two S        

sodium hydroxide
calcium hydroxide
Barium hydroxide
magnesium hydroxide
Cupric hydroxide
Koh
Aluminum hydroxide
NaOH
Ca (OH) Two
Ba (OH) Two
Mg (OH) Two
Cu (OH) Two
KOH
Al (OH) Three
Ferric hydroxide
Ferrous hydroxide
Fe (OH) Three
Fe (OH) Two
Common organic compounds
methane
methanol
ethanol
acetic acid
CH Four
C Two H Two
CH Three OH
C Two H Five OH
CH Three COOH

methane
acetylene
methanol
ethanol
acetic acid
CH Four
C Two H Two
CH Three OH
C Two H Five OH
CH Three COOH
common Crystalline hydrate
Gypsum
CaSO Four 2H Two O
CaSO Four H Two O
FeSO Four 7H Two O
rust    
CuSO Four 5H Two O
Na Two CO Three 10H Two O
Fe Two O Three XH Two O    

Auragreen
Gypsum
Plaster
alum
Melanterite
Cu Two (OH) Two CO Three
CaSO Four 2H Two O
CaSO Four H Two O
KAl (SO Four ) Two 12H Two O
FeSO Four 7H Two O
Blue vitriol
Sodium carbonate crystal
CuSO Four 5H Two O
Na Two CO Three 10H Two O
Common fertilizer
urea
NH Four NO Three
(NH Four ) Two SO Four
NH Four HCO Three
KH Two PO Four

urea
ammonium nitrate
Ammonium sulphate
Ammonium hydrogen carbonate
Potassium dihydrogen phosphate
CO (NH Two ) Two
NH Four NO Three
(NH Four ) Two SO Four
NH Four HCO Three
KH Two PO Four
Carbon dioxide hydrogen chloride calcium chloride sodium hydroxide silver nitrate sodium chloride
CO Two HCl CaCl Two NaOH AgNO Three NaCl
Aluminium chloride Sodium bicarbonate Ammonium hydrogen carbonate potassium permanganate manganese dioxide methane
AlCl Three NaHCO Three NH Four HCO Three KMnO Four MnO Two CH Four
Ethanol / alcohol water iron sodium carbonate
Hydrogen peroxide solution
copper
C Two H Five OH H Two O Fe Na Two CO Three H Two O Two Cu

Hydrogen peroxide solution
( Hydrogen peroxide solution )

Chemical formula Basic overview

Definition
Definition
use
The element symbol composition.
Significance
  1. A substance and composition of the elements
  2. Represents a molecule and molecules contained in the atomic number (example: H represents a hydrogen molecule by two hydrogen atoms)
Writing principle
Positive and negative valence algebra and zero. Cases:
Is the total price = (+1 * 2=+2)
The total number of negative valence =-2
Type the amount
The sum of the atomic weight of the atoms in the formula, the amount of chemical called type. (by the molecular composition of the material is also called molecular weight)

use
The element symbol composition.
Significance
A substance and composition of the elements
Represents a molecule and molecules contained in the atomic number (example: H represents a hydrogen molecule by two hydrogen atoms)
Positive and negative valence algebra and zero. Cases:
Is the total price = (+1 * 2=+2)
The total number of negative valence =-2
The sum of the atomic weight of the atoms in the formula, the amount of chemical called type. (by the molecular composition of the material is also called molecular weight)

Chemical formula Writing rules

The elemental chemistry style of writing:
The elemental composition of the first write Element symbols Then, in the lower right corner with symbols of figures constitute a Single molecule The atomic number. Rare gas Is composed of atoms, usually with elements of symbols to indicate their chemical formula. Metal Elemental And the structure of solid non metals is more complex, it is also customary to express their chemical formula with symbols.
A compound of formula method:
Firstly, according to the positive negative after sequential composition of all compounds Element symbols Then, in each symbol of the lower right corner of the figures with the atomic number of the element in each molecule. A certain order usually refers to: oxygenated compounds with another element, generally the oxygen element symbols on the right; Hydrogen Other elements and compounds, generally to hydrogen symbols on the left hand; metallic element Hydrogen and Non metallic elements Composition in general to nonmetallic element symbols on the right. Compound directly by ion, its chemical formula commonly used the most simple integer ratios of ions.
Be careful:
When the number of elements of atomic ratio is 1, 1 omit; oxide chemical formula writing, the oxygen element symbols in the right, another element symbols written on the left, such as CO2; compound composed of metal elements and non-metallic elements, the writing of chemical formula, general the metal element symbols written on the left, non metallic element symbols in the right, such as NaCl. Positive and negative valence algebra and zero.

Chemical formula The general introduction of law

The chemical method is generally pronounced "X X" from right to left, such as "CuO" read Copper oxide . When more than one of a number of atoms in the molecule, but also read particle number, such as "P Two O Five "Read Phosphorus pentoxide . With acid Atomic group To read "X acid such as" CuSO X " Four "Read Copper sulphate . And to read "hydroxide X", such as "NaOH" called sodium hydroxide. Also note that the valence of iron iron containing compounds in reading, reading +3 valence iron (such as "FeCl Three "Read" Ferric chloride "), +2 price is read as ferrous (such as" FeCl Two "Read" Ferrous chloride "). If contains Crystal water Should the number of crystal water is read out and read "X hydration X", such as "CuSO Four 5H Two O "read" five copper sulfate hydrate "(Note: the number of crystallization water is 1, the number should be read, read as" a hydrated X ").

Chemical formula The content of said

The chemical formula can be said 1 molecules, and the molecular composition of elements and types Atomic number If you want to say, a few molecules of a substance, can add the coefficients in the chemical formula of the material. The molecular marked as the 2 number. Molecular oxygen Available 2O Two Express, Fe3O4 You can use Fe Three O Four Said.
Calculation formula
Calculation relative molecular mass
The same element The relative atom The quality of its atomic number multiplication, the sum of the relative atomic mass of different atoms.
The quality of each component in the calculation of element ratio
The quality of each element in the formula is the sum of the relative atomic mass of each element is the ratio of the
Calculation of a certain element in the compound quality
Formula: compound quality = an element X of a compound quality The mass fraction of elements