Keywords acid dry acid, alkali dry alkali, oxidation can not be dry reduction,
Widely used neutral desiccant,
You can only do it if you don't react.
Physical properties of sulfur:
Topaz is fragile, twice as fragile as water, slightly soluble in alcohol, soluble in carbon disulfide, insoluble in water, melting point 1 12, boiling point 444. The density is twice that of water.
Characteristics of hydrogen sulfide:
Colorless, smelly, toxic, 2.6, hydrogen and sulfur, but also blue flame, incomplete combustion produces sulfur. (1 volume of water dissolves 2.6 volume of H2S, which is decomposed into elemental hydrogen and sulfur under certain conditions, with reducibility, flammability and blue flame).
Chemical properties of benzene: taking halonitrate and burning sulfur.
Chemical properties of halogenated hydrocarbons: alkaline water extraction, alcohol and alkali elimination.
The relationship between valence and atomic number of short-period elements;
Odd order is odd and even order is even.
Characteristics of combustion in oxygen;
The embers in oxygen can be polyene, and white smoke diffuses when phosphorus burns.
Iron ene radiates from Mars, and the sulfur blue purple light is really brilliant.
Combustion characteristics in chlorine gas;
Phosphorus burns chlorine with thick smoke, while copper burns brown smoke.
The flame of hydrogen combustion is pale, and sodium combustion produces hoarfrost violently.
Common elemental valence songs:
Monovalent hydrogen, lithium, sodium, potassium, silver,
Divalent oxygen, magnesium, calcium, barium, zinc,
Copper, mercury one, two, iron two, three,
Carbon, tin and lead exist in two or four places,
Sulfur is minus two and four or six,
Negative three to five nitrogen and phosphorus,
Halogen minus one, one, three, five, seven,
Trivalent. Remember boron, aluminum and gold.
Description: The above eight ballads summarize the valence of 236 common elements, including fixed price and variable price.
Song of solubility of salt;
Potassium, sodium, ammonium salts and nitrates;
Removing silver and mercury by chloride;
Removing barium and lead with sulfate;
Carbonic acid, phosphate, only soluble in potassium, sodium and ammonium.
I. Chemical calculation
If the chemical formula is to be balanced, the equation must be replaced by scalar.
The unit should be unified up and down, and the left and right multiples should be equal.
If the mass unit is grams, the standard temperature and pressure gas are equivalent to liters.
When two known quantities are encountered, they should be considered insufficient.
Content loss and output, multiplication and division should be distinguished.
Second, gas preparation
From the beginning to the end of gas production, each operation step has its own position.
The generating device is located in the head, followed by the cleaning device.
Impurity removal devices are divided into dry type and wet type, and the drying device retains water;
Gas gathering should be divided into gas and water, and property experiments should be divided in order.
The poisonous gas must be eliminated and the correct getter must be selected.
Sometimes there are several devices, and the basic sequence cannot be lost.
Occasionally there are small changes, and carefully look for the relative position.
Thirdly, hydrogen reduces copper oxide.
Clamp the test tube and introduce hydrogen at the beginning of the experiment.
Light the lamp when the air is exhausted, and stop hydrogen when it cools to room temperature.
If you light the lamp first, it will explode. If you stop hydrogen first, it will oxidize.
From black to red, changeable, Yunchang's face smiled.
First, the valence formula
Univalent potassium, sodium, silver fluoride and hydrogen,
Bivalent calcium, barium, magnesium and zinc oxide,
Tetrasilicon pentavalent phosphorus trialuminum;
23 iron, 24 carbon.
246 sulfur completed,
Copper and mercury are the most common divalent elements.
Second, the solubility formula
Potassium sodium ammonium salt dissolves quickly in water, ①
Remove barium, lead and calcium with sulfate. ②
Chloride insoluble silver chloride,
Nitrate solution is transparent. ③
Everything in the formula will sink. ④
Three. Formula of element sequence 1-20 (5)
Hydrogen, helium, lithium, beryllium and boron,
Carbon, nitrogen, oxygen, fluorine and neon;
Sodium, magnesium, aluminum, silicon and phosphorus,
Sulfur, chlorine, argon, potassium and calcium.
Four, metal activity formula
Potassium, calcium, sodium, magnesium and aluminum.
Zinc, iron, tin, lead and hydrogen,
Copper, mercury, silver, platinum and gold.
Note: ① Potassium, sodium and ammonium salts are all soluble in water;
② Only barium sulfate, lead sulfate and calcium sulfate are insoluble in sulfate;
③ Nitrates are all soluble in water;
④ All salts not involved in the formula are insoluble in water;
⑤ 1 ~ 20, another homophonic limerick can help you remember:
Don't jump, little boy,
Charcoal eggs raise boiling milk,
That girl is raining,
Luniuya Xialai
Formula for making oxygen:
Manganese dioxide potassium chlorate; Stir well and heat. Oxygen plant has its own characteristics; The bottom is high and the mouth is slightly inclined.
Gas gathering formula:
Exhaust method interacting with water; According to the density. Insoluble and slightly soluble drainage methods; The obtained gas has high purity.
Electrolytic water formula:
Positive oxygen contributes to combustion; Negative hydrogen will burn badly.
Solubility of salt:
Potassium, sodium, ammonium and nitrate are all soluble, but hydrochloric acid is insoluble in silver and mercurous chloride. Sulfate insoluble barium, lead and carbon phosphate insoluble. Most acids are soluble in alkali, but only potassium, sodium, ammonium and barium are soluble.
Formula for making oxygen:
Manganese dioxide potassium chlorate; Stir well and heat.
Oxygen plant has its own characteristics; The bottom is high and the mouth is slightly inclined.
Gas gathering formula:
Exhaust method interacting with water; According to the density.
Insoluble and slightly soluble drainage methods; The obtained gas has high purity.
Electrolytic water formula:
Positive oxygen contributes to combustion; Negative hydrogen will burn badly.
Valence formula:
Principal valence States of common elements
Fuwan iodine negative; Silver monohydride and potassium sodium.
Remember the negative two of oxygen first; Magnesium, calcium, barium and zinc were positive.
Positive three is aluminum positive silicon; Let's change the price again.
All metals are positive electrodes; One, two, copper, two, three iron.
Manganese is 24 and 67; Remember the second and fourth carbons.
Non-metallic negative body is uneven; Chlorine is negative, positive and 157.
Nitrogen and phosphorus are negative three and positive five; Different phosphorus, three nitrogen, two four.
Sulfur has negative two plus four six; Remember, it's cooked after use.
Common root price formula:
Monovalent ammonium nitrate; Hydrohalide hydroxide.
Permanganate chlorate; Perchlorate acetate.
Bivalent sulfate carbonate; Manganese bisulfate.
Temporarily record ammonium as positive; Negative number three has phosphate.
Metal activity sequence table:
(senior high school) potassium, calcium, sodium, magnesium, aluminum, manganese, zinc, chromium, iron, nickel, tin, lead and hydrogen; Copper, mercury, silver and platinum.
Valence formula 2
Monovalent potassium sodium silver hydrogen chloride; Bivalent calcium, barium, magnesium and zinc oxide,
Aluminum, silicon, nitrogen and phosphorus; 23 iron, 24 carbon,
Sulfur is pure; Cu2+is the most common.
Solubility of salt:
Potassium, sodium, ammonium and nitrate are all soluble, but hydrochloric acid is insoluble in silver and mercurous chloride.
Sulfate insoluble barium, lead and carbon phosphate insoluble.
Most acids are soluble in alkali, but only potassium, sodium, ammonium and barium are soluble.
Turn first and fold first, the temperature is high and the pressure is high! (Chemical Balance Image Theme)
Preparation of ethylene:
Alcohol sulfuric acid is one to three, and catalytic dehydration is sulfuric acid. The temperature is as high as 170, and ethylene is produced without ether.
The reaction liquid is black, which is caused by alcohol carbonization and sulfuric acid.
silver mirror reaction
The silver mirror reaction is very simple, producing ammonium carboxylate, two silver monohydrates and three ammonia.
Filtering operation experiment
The funnel angle of the glass rod and filter paper in the beaker of bucket frame is the same.
Don't forget to let it stand before filtering.
Neutralization titration: control the stopper with your left hand, shake the bottle with your right hand, keep your eyes on the solution, and immediately stop discoloration.
The older you get, the dirtier you get. If there is anything wrong, please take care!
Laboratory ethylene production: sulfuric acid and alcohol are three to one. Quickly raise the temperature to 170, add broken porcelain to boil, and collect ethylene by drainage.
The sequence of metal activities: Jiamei donkey, whose new hoof likes to pull lightly, weighs 100 kg.
Meaning: There is a beautiful donkey named Jia Gai who likes to carry (pull) light goods with new hooves. According to statistics, it's only 100 Jin.
Organic chemistry is not difficult, but remembering the general formula is the key.
Only C and H are called hydrocarbons, and their structures are chain or cyclic.
The double bond is alkyne with triple bond and the single bond is alkane.
Aliphatic in the chain, aromatic with benzene ring.
Isomerism uses the molecular formula, and the general formula is universal homology.
Alkane substitution of olefins, functional groups of derivatives.
Carboxylic acids are hydroxyl-linked hydrocarbon groups, called aldols and carboxylic acids.
Carbonyl ether bond and amino group, and the derivative is ketoether amine.
Benzene with hydroxyl group is called phenol, and naphthalene is a parallel biphenyl.
Going to H and adding O is called oxidation, and going to O and adding H is called reduction.
Alcohol is oxidized to ketone and aldehyde is oxidized to carboxylic acid.
Carboxylic acid is stronger than carbonic acid and carbonic acid is stronger than carbonic acid.
Photohalogenation in side chain, catalytic halogenation in benzene ring.
Halogenated derivatives of hydrocarbons, halogen can be replaced by hydroxyl.
A small molecule is eliminated to form dilute acid and halogen acid.
Potassium and sodium can exchange hydrogen in alcohol, and aldehydes can be distinguished by silver mirror reaction.
Copper hydroxide polyol, the solution is dark red and blue when mixed.
Alcohol and carboxylic acid are added to form esters, which are hydrolyzed to alkyd resin.
Phenol turns white in bromine and starch turns blue in iodine.
Amino acids are acid-base, formic acid, acid and aldehyde.
Polymerization monomer changes the chain link and breaks π bond in series.
Ever-changing and interesting, unlimited scenery to climb. Perfect the answer Perhaps, Happy 2007-08-3 1 13:34 Evaluate whether the answer solves the problem (participate in the evaluation for 0 times) and whether it can be solved: 0 Evaluation is successful and original plus 2! Part of the solution: 0 evaluation is successful and original plus 2! Unable to solve: 0 original plus 2 after successful evaluation! Whether the original answer (participated in the evaluation for 0 times) is original: 0 times of evaluation is successful and original plus 2! Non-original: 0 evaluation success, original plus 2! Satisfied with the answer, haha! There are quite a few formulas ~ ~
1. The following is about valence (two short poems)
Regular price song
Keywords monopotassium, sodium silver ammoniate,
N- dicalcium magnesium barium and zinc,
Copper 12, iron 23,
Three aluminum, four silicon and two carbon.
Negative price song
Negative monohydroxide nitrate compound pill,
Negative disulfate, carbonate, oxygen and sulfur,
Negative nitrogen valence changes chlorine, phosphorus, sulfur, manganese and carbon,
Roots and nonmetals mostly appear at negative prices.
Chlorine, manganese, sulfur, nitrogen and phosphorus are trivalent or tetravalent and can be recorded separately. In addition, note that the valence of elements in all simple substances is 0. The rest are the above two poems. Two poems taught by junior high school chemistry teacher. Personally, I find it particularly useful, especially "regular songs".
2. The following is about redox reaction (six words)
"Oxygen is lost, and it is still falling."
Explanation: "oxygen-rising and oxygen-losing" means that in the redox reaction, the elements with increased valence lose electrons and are oxidized.
"Falling back", on the contrary, is to reduce the valence, gain electrons and reduce.
(Supplementary explanation, extending above, we can also draw the conclusion that oxidized substances are used as reducing agents to generate oxidized products; The reduced substance is used as an oxidant to generate a reduced product. )
3. The following are eight important essential amino acids (9 words)
"It's cold, but it's cool and can cool off the heat."
Explanation: "Ben" and "benzene" are homophonic, representing phenylalanine. "Lai" and "Lai" are homophonic, representing lysine. "Cool" and "bright" are homophonic, representing leucine. "Dan" is homophonic with "egg" and stands for methionine. "Yes" and "color" are homophonic, representing tryptophan. "One cool" and "different bright" are homophonic, representing isoleucine. "Jie" and "Val" are homophonic, representing Val. "Summer" and "Su" are homophonic, representing threonine.
(phenylalanine, lysine, leucine, methionine, tryptophan, isoleucine, valine and threonine are eight important essential amino acids. )
I think the above three categories are better to use, but there are still many, and I can even summarize them myself. There are many periodic rates of elements, and I usually summarize them myself, which is very interesting. If you are interested, try it yourself!