Ask about the mantra of chemistry, what are the mantras of chemistry?

1. Chemical calculations.

The chemical formula should be balanced, the equation must be pure, the unit should be unified up and down, and the left and right multiples should be equal.

If the unit of mass is in grams, the standard gas should be lit up, and if two known quantities are encountered, they should be carried out according to the insufficiency.

Content loss and yield, multiplication and division should be distinguished.

2. Gas preparation.

From the beginning to the end of gas preparation, the operation steps are in place, the generating device is located at the head, the washing device is followed by the cleaning device, the impurity removal device is divided into dry and wet, and the drying device retains the water;

Gas collection should be divided into gas and water, property experiments should be divided into sequences, toxic gases must be removed, and the inspiratory reagent should be selected.

Sometimes there are a few fewer devices, the basic order can not be lost, occasionally there are small changes, and the relative position is carefully sought.

3. Reduction of copper oxide by hydrogen.

The test tube is clamped and tilted downward, and the experiment begins with hydrogen first, and then the lamp is lit when the air is exhausted, and the hydrogen is stopped after cooling to room temperature.

Light the lamp first, it will **, stop hydrogen first, it will oxidize, change from black to red, Yun Chang smiled on his face haha.

Potassium, sodium, hydrogen and silver are positive one price.

Calcium, magnesium, barium, zinc positive bivalent.

Copper is one and two and aluminum is three.

Oxygen is usually minus bivalent.

Chlorochlorobromoiodine negative monovalent.

Iron has positive two and positive three.

Hydrogen, helium, lithium, beryllium, boron.

Carbon, nitrogen, oxyfluorone, neon.

Sodium, magnesium, aluminum, silicon, phosphorus.

Calcium potassium argon thiocide.

Negative) monovalent hydroxide nitrate.

negative) divalent sulfate carbonate.

Positive monovalent is remembered to be ammonium.

Metal Activity Order Table:

Potassium, calcium, sodium, magnesium, aluminum.

Zinc, iron, tin, lead, hydrogen.

Copper, mercury, silver, platinum.

1. Monovalent potassium sodium and silver chloride. 2. Divalent oxygen, calcium, barium, magnesium and zinc.

3. Trialuminum, tetrasilicon, pentavalent phosphorus.

4. Two-three-iron-two-tetracarbon.

5. 246 sulfur is complete.

6. Copper-mercury bivalent is the most common.

7. Positive and negative prices should be recorded.

8. Don't forget that the unit quality price is zero.

9. Negative hydroxide mononitrate.

10. Negative disulfite carbonate.

11. Remember the phosphate group of minus three.

12. The positive monovalent is ammonium.

13. Hydrogen, sodium, potassium, silver is positive monovalent, calcium, barium, magnesium and zinc are positive bivalent.

14. One or two copper, two iron iron, two four hexasulfur and two tetracarbon.

15. Three aluminum, four silicon, three or five phosphorus, and manganese, chloride and nitrogen.

1. Oxygen production formulapotassium manganese chlorate dioxide; Mix evenly and add heat.

Oxygen concentrators have characteristics; The bottom is high and the mouth is low and slightly sloping.

2. Gas collection formulaInteraction with water with exhaust method; Set up and down according to the density.

insoluble micro-dissolution drainage method; The resulting gas is of high purity.

3. Solubility formula:Potassium, sodium, ammonium, and nitrate are all soluble, and hydrochloride is insoluble in silver and mercury.

Sulfate is insoluble in barium and lead, and carbon phosphate is mostly insoluble.

Hydrogen-sulfur-soluble four positions, potassium sodium and magnesium barium.

Most acids are less soluble in alkali, and only potassium, sodium, ammonium, and barium are soluble.

4. Common valency formulas:Chlorochlorobromoiodine negative monovalent. N-monohydrogen silver with potassium sodium. The minus two of oxygen should be remembered first; n-dimagnesium, calcium, barium and zinc.

positive three is aluminum, positive four silicon; Let's put the price change down. All metals are regular; One or two coppers come two or three irons. Manganese is 24 and 67; Carbon 24 to keep in mind.

non-metallic negative main is uneven; Chlorine minus one positive one five seven. Nitrogen and phosphorus minus three and plus five; Different phosphorus, three nitrogen, two or four. Sulfur has minus two, positive, four-six; It will be cooked when you use it while memorizing it.

5. Preparation of the quantity and concentration solution of the substance:Calculate the weighing and take the step clear, dissolve and transfer and then set the volume. Don't forget to wash at room temperature, shake the label well, and you're done.

Chemical main group element formula:

The first main family: hydrogen, lithium, sodium and potassium, such as cesium and francium (please Li Na to join the private interview) The second main family: beryllium, magnesium, calcium, strontium, barium, radium (comparable to Gates, thunder).

The third main family: boron, aluminum, gallium, indium, thallium (touching the girl to marry him).

The fourth main group: carbon, silicon, germanium, tin, and lead (westward migration of returnees).

Fifth main group: ammonia, phosphorus, arsenic, antimony, bismuth (eggs are closed).

The sixth main group: oxysulfur, selenium, tellurium, polonium (cattle breeding).

The seventh main family: chlorochlorobromoiodine astatine (father and daughter embroidered with love).

Eighth main group: ammonia, neon, argon, krypton, xenon, radon (harm to the first move).

Extended information: The main group of elements is a chemical classification of elements, which refers to the elements in the S and regions of the periodic table. Another definition of a major group element is a chemical element in which the number of electrons in the electron shell except for the outermost electron shell is full electrons.

In the periodic table, except for transition metals, lanthanides, actinides, and noble gases, they are all major group elements.

1. Basic reaction types:Chemical reaction: many change one Decomposition reaction: one becomes many.

Displacement reaction: one for one metathesis reaction: exchange of ions.

2. Valency (positive valence) of common elements:Monovalent potassium, sodium, hydrogen and silver, bivalent calcium, magnesium, barium and zinc, trivalent metal element aluminum.

157 variable chlorine, 245 nitrogen, sulfur 46, 35 phosphorus, 24 carbon.

One or two copper, two three iron, two four six or seven manganese special.

3. Steps to produce oxygen in the laboratory:"Tea (check), Zhuang (loading), fixed, pointing, receiving, profit (leaving), and interest (extinguishing)".

Check the airtightness of the device, "load" the drug, and connect the device.

Set the "test tube" fixed on the iron frame "point" and light the alcohol lamp for heating.

Collect the "gas" away from the "conduit" and move it away from the water.

"Extinguish" to turn off the alcohol lamp and stop the heat.

Chemistry is a kind of natural science, mainly at the molecular and atomic levels, studying the composition, properties, structure and change laws of matter, and creating new substances (the essence is molecules that do not exist in nature).

The world is made up of matter, and there are two main forms of change: chemical and physical changes (and nuclear reactions).

Different from particle physics and nuclear physics, which study smaller scales, the material structure of atoms, molecules, and ions (clusters) studied in chemistry interact with chemical bonds and intermolecular forces, and the scale in which they are located is the closest to the macrocosm in the microscopic world, so their natural laws are also most closely related to the physical and chemical properties of substances and materials in the macrocosm of human existence. As an important bridge between the microscopic and macroscopic material worlds, chemistry is one of the main methods and means for human beings to understand and transform the material world.

Chemistry mantra:

1. In order to remember the structure of the periodic table, there is such a slip: eighteen longitudinal rows and seven horizontal rows, one hundred and four tables contain seven main, seven vices, zero and eight, three short, three long and one incomplete.

2. In the periodic law, the relationship between the parity of the main valence of an element and the parity of its ordinal number:"The price is odd and the order is strange, and the price is even and the order can be remembered as homophonic: marry (price) chicken (odd) with chicken, marry dog (even) with dog.

3. The writing method of isomers is the formula of carbon chain shortening: the main chain is long to short, the branch chain is whole to scattered, the position center is to the edge, and the arrangement is between neighbors.

4. The top 10 elements in the earth's crust: formula: raising a girl to stick the lid of the pot, which family does not have green vegetables (oxy-silicon, aluminum, iron, calcium, sodium, potassium, magnesium, hydrogen, titanium).

5. Solubility formula: potassium, sodium, ammonium nitrate soluble, hydrochloric acid in addition to mercury, sulfuric acid insoluble with barium lead, carbonic acid is mostly insoluble, and dissolved alkali is only potassium, sodium and barium ammonia.

6. Common valency formulas in junior high school: monovalent hydrochloride, potassium, sodium silver, divalent oxygen, calcium, barium, magnesium, zinc, trialuminum, tetrasilicon, pentavalent phosphorus, copper and mercury, bivalent are the most common, 23 iron, 24 carbon, 246 sulfur are all available, and 235 valent nitrogen accounts for all.