Basic knowledge points of chemistry in senior two 1
I. Methods and procedures for studying the properties of substances
1. Basic methods: observation, experiment, classification and comparison.
2. Analyze, synthesize and infer the observed phenomena by comparative method, and draw a conclusion.
Second, the nature of sodium and its compounds:
1. Sodium slowly oxidizes in air: 4Na+O2==2Na2O.
2. Sodium burns in air: 2Na+O2 ignites = ====Na2O2.
3. The reaction between sodium and water: 2na+2h2o = 2nNaOH+H2 =
Phenomenon: ① sodium floats on the water; (2) melting into silvery white balls; (3) swimming around the water; (4) accompanied by a noisy noise; ⑤ Water dripping with phenolphthalein turns red.
4. The reaction between sodium peroxide and water: 2Na2O2+2H2O = 4NaOH+O2 =
5. The reaction between sodium peroxide and carbon dioxide: 2Na2O2+2CO2=2Na2CO3+O2.
6. Sodium bicarbonate is divided into 2 nahco3 △ = = Na2CO3+H2O+CO2 =
7. The reaction between sodium hydroxide and sodium bicarbonate: NaOH+NaHCO3=Na2CO3+H2O.
8. Introduce carbon dioxide into the sodium carbonate solution: Na2CO3+CO2+H2O=2NaHCO3.
Three. Properties of chlorine and its compounds
1. Reaction of chlorine with sodium hydroxide: Cl2+2NaOH=NaCl+NaClO+H2O.
2. Iron wire burns in chlorine: 2Fe+3Cl2 ignition ===2FeCl3.
3. Preparation of bleaching powder (chlorine can flow into lime slurry) 2cl2+2ca (OH) 2 = CaCl2+Ca (clo) 2+2h2o.
4. Reaction between chlorine and water: Cl2+H2O=HClO+HCl.
5. Sodium hypochlorite deteriorates in air: NaClO+CO2+H2O=NaHCO3+HClO.
6. Calcium hypochlorite deteriorates in air: Ca(ClO)2+CO2+H2O=CaCO3↓+2HClO.
Fourthly, the relationship between physical quantities centered on the quantity of matter.
1. Amount of substance n (mole) =N/N(A)
2. the amount of substance n (mole) = m/m.
3. The amount of gaseous substances under standard conditions n(mol)=V/V(m)
4. The amount of solute in the solution n(mol)=cV.
Verb (abbreviation for verb) colloid:
1. Definition: A dispersion system with dispersion particle diameters between 1 and 100 nm.
2. Colloidal characteristics:
(1) Tindal phenomenon
② Aggregation and precipitation
③ Electrophoresis
④ Brownian motion
3. Colloidal purification: dialysis
Basic knowledge points of chemistry in senior two II.
Chlorine and its compounds, SiO2+2NaOH==Na2SiO3+H2O,
① Physical properties: generally yellow-green, denser than air, irritating, soluble in water and toxic.
Chemical properties: chlorine atoms can easily get electrons, which makes them active nonmetallic elements. Chlorine reacts with metals and nonmetals. And is commonly used as an oxidant. When it reacts with water and alkali solution, it will have its own redox reaction, which is used as both oxidant and reductant.
Extension 1, Chlorine water: Chlorine water is yellow-green, a small amount of Cl2 reacts with water (Cl2+H2O==HCl+HClO), most of which still exists in molecular form, and the main solute is Cl2. Fresh chlorine water contains particles such as Cl2, H2O, HClO, H+, Cl-, ClO- and OH-.
Expansion 2. Hypochloric acid: Hypochloric acid (HClO) is weaker than H2CO3 and mainly exists in the form of HClO molecules in solution. It is a weak acid with strong oxidation (sterilization, disinfection and bleaching) and easy to decompose (HCl and O2). Expansion 3. Bleaching powder: Hypochlorite is more stable and easier to store than hypochlorous acid. Bleaching powder is prepared from chlorine dioxide and lime milk in industry. The main components are CaCl2 _ 2 and Ca (clo) _ 2, and the effective component is Ca (clo) _ 2, which must react with acid (or CO2 in the air) to generate hypochlorous acid in order to play a bleaching role.
sulphur dioxide
① Physical properties: colorless, pungent, gaseous, toxic, easy to liquefy, soluble in water (1: 40), and denser than air.
② Chemical properties:
A, acid oxide: can react with water to generate corresponding acid-sulfurous acid (medium strong acid): SO2+H2O H2SO4 can react with alkali to generate salt and water: SO2+2NaOH==Na2SO3+H2O, SO2+Na2SO3+H2O==2NaHSO3b, which has bleachability: it can make magenta solution fade, but it belongs to temporary bleaching.
C, reducible: SO2+Cl2+2H2O==H2SO4+2HCl.
Basic knowledge points of chemistry in senior two 3
I. Benzene C6H6
1, physical properties: colorless liquid, with special smell, less density than water, toxic, insoluble in water, soluble in organic solvents, and a good organic solvent in itself.
2. Structure of benzene: The bonds between six carbon atoms in C6H6 (regular hexagonal plane structure) benzene molecule are identical, the bond energy of carbon-carbon single bond is greater than that of carbon-carbon single bond and less than twice that of carbon-carbon single bond, the bond length is between that of carbon-carbon single bond and double bond, and the bond angle is 120.
3. Chemical properties
The oxidation reaction of (1) 2c6h6+15o2 =12co2+6H2O (open flame smoke) can't make the acid potassium permanganate fade.
(2) substitution reaction
① The function of iron powder: react with bromine to generate iron bromide as catalyst; The colorless density of bromobenzene is higher than that of water.
(2) Benzene reacts with nitric acid (represented by HONO2 _ 2) to produce a colorless, water-insoluble and toxic oily liquid-nitrobenzene. Heating+HONO _ 2+H2O in a water bath at 50-60℃, using concentrated sulfuric acid as catalyst and dehydrating agent.
(3) Addition reaction
Using nickel as catalyst, benzene reacts with hydrogen to produce cyclohexane +3H2.
Second, ethanol CH3CH2OH
1, physical properties: colorless liquid, with special fragrance, less density than water, and miscible with water in any proportion. How to test whether ethanol contains water: add anhydrous copper sulfate; How to obtain anhydrous ethanol: add quicklime and distill.
2. structure: CH3CH2OH (containing functional group: hydroxyl)
3. Chemical properties
(1) The reaction between ethanol and sodium metal: 2ch3ch2oh+2na = 2ch3ch2ona+H2 = (substitution reaction).
(2) Oxidation reaction of ethanol
① Combustion of ethanol: CH3C2OH+3O2 = 2CO2+3H2O.
② Catalytic oxidation of 2CH3CH2OH+O2=2CH3CHO+2H2O by ethanol.
③ Oxidation of ethanol by strong oxidant.
CH3CH2OH
Three. Acetic acid (common name: acetic acid) CH3COOH
1, physical properties: it is a colorless liquid at room temperature, with strong pungent smell and easy to form ice-like crystals, so pure acetic acid is also called glacial acetic acid, which is miscible with water and alcohol in any proportion.
2. structure: CH3COOH (containing carboxyl group, which can be regarded as composed of carbonyl group and hydroxyl group)
3. Important chemical properties of acetic acid
Acidity of (1) acetic acid:
Weakly acidic, but more acidic than carbonic acid, with the commonality of acid.
① Acetic acid can turn purple litmus test solution red.
② Acetic acid can react with carbonate to generate carbon dioxide gas, which can be used for scale removal (mainly CaCO3): 2ch3cooh+CaCO3 = (CH3 COO) 2ca+H2O+CO2 = acetic acid can also react with sodium carbonate to generate carbon dioxide gas: 2ch3cooh+Na2CO3 = 2ch3coona+H2O+CO2 = The above two reactions can prove acetic acid.
(2) Esterification of acetic acid
(Acid dehydroxylation, alcohol dehydrogenation and esterification are substitution reactions)
Ethyl acetate is the main product of the reaction between acetic acid and ethanol. It is a colorless, fragrant, water-insoluble oily liquid with lower density than water. In the experiment, saturated sodium carbonate was used to absorb volatile ethanol and acetic acid to reduce the solubility of ethyl acetate. During the reaction, glacial acetic acid, anhydrous ethanol and concentrated sulfuric acid were used as catalysts and water absorbents.
Basic knowledge points of chemistry in senior two 4
Nitrogen and its compounds
I. Nitrogen (N2)
A, physical properties: colorless and odorless, insoluble in water, slightly smaller than air, with a volume fraction of about 78%b in air, molecular structure: molecular formula -N2, electron-,structural formula-n ≡ n.
C, chemical properties: the structure determines the properties, and the nitrogen-nitrogen triple bond is very strong and difficult to destroy, so the properties are very stable.
① Reaction with H2: N2+3H22NH3
② Reaction with oxygen: N2+O2 = = = = = 2NO (colorless, water-insoluble gas, toxic).
2NO+O2 = = 2NO2 (reddish brown, pungent smell, gas soluble in water, toxic) 3NO2+H2O = = 2HNO3+NO, so we can remove NO2 from NO with water: 4NO+3O2+2H2O = = 4HNO3, 4NO2+O2+2H2O = = 4HNO3, ammonia (NH3
A. Physical properties: colorless, pungent, less dense than air, easily soluble in water (1∶700), easily liquefied, and absorbs a lot of heat when vaporized, so it is often used as a refrigerant.
B, molecular structure: molecular formula -NH3, electron-,structural formula-H-N-H.
C, chemical properties:
① Reaction with water: NH3+H2ONH3? H2O (ammonia monohydrate) NH4++OH-, so the ammonia solution is alkaline.
② Reaction with hydrogen chloride: NH3+HCl==NH4Cl, phenomenon: white smoke.
D preparation of ammonia gas: principle: ammonium salt and alkali are heated to generate ammonia gas.
Equation: 2nh4cl+Ca (OH) 2 = = 2nh3 ↑+2h2o+CaCl2.
Device: the same as the oxygen production device.
Collection: downward exhaust method (drainage method cannot be used because ammonia is very soluble in water).
(Note: there is a lump of cotton at the mouth of the collection test tube to prevent air convection, slow down the exhaust speed and collect pure ammonia)
Verify whether ammonia gas is completely collected: use wet red litmus paper near the test tube mouth. If the test paper turns blue, the ammonia gas is completely collected.
Drying: alkali lime (mixture of CaO and NaOH)
Basic knowledge points of chemistry in senior two 5
1, the rate of chemical reaction
(1) concept: chemical reaction rate is usually expressed by the decrease of reactant concentration or the increase of product concentration per unit time (both positive values).
Calculation formula:
① Unit: mol/(liter/second) or mol/(liter/minute)
②B is a solution or a gas. If B is a solid or a pure liquid, the rate is not calculated.
(3) The above is the average rate, not the instantaneous rate.
(4) Important laws:
Ratio = equation coefficient ratio
Rate of change = coefficient ratio of equation
(2) Factors affecting the chemical reaction rate:
Internal cause: (the main factor) is determined by the structure and properties of the substances involved in the reaction.
External factors: ① temperature: increase the temperature and speed.
② Catalyst: generally, the reaction speed is accelerated (positive catalyst).
③ Concentration: increase the concentration of reactant C and increase the rate (only solution or gas can have concentration).
④ Pressure: increase the pressure and speed (applicable to the reaction with gas).
⑤ Other factors, such as light (ray), solid surface area (particle size), reactant state (solvent), galvanic cell, etc. , will also change the chemical reaction rate.
2, the limit of chemical reaction-chemical equilibrium
(1) Under certain conditions, when a reversible reaction proceeds until the positive reaction rate is equal to the reverse reaction rate, the concentrations of reactants and products will not change and reach a seemingly static "equilibrium state", which is the limit that this reaction can reach, that is, the chemical equilibrium state.
The movement of chemical equilibrium is influenced by temperature, reactant concentration, pressure and other factors. The catalyst only changes the chemical reaction rate and has no effect on the chemical equilibrium.
Under the same conditions, reactions that proceed in both positive and negative directions at the same time are called reversible reactions. The reaction from reactant to product is usually called positive reaction. The reaction from product to reactant is called reverse reaction.
In any reversible reaction, the forward reaction should be carried out simultaneously with the reverse reaction. The reversible reaction can't go through to the end, that is, no matter how far the reversible reaction goes, the amount of any substance (reactant and product) can't be zero.
(2) Characteristics of chemical equilibrium state: inverse, dynamic, equal, constant and variable.
① Inverse: The research object of chemical equilibrium is reversible reaction.
② Dynamic: dynamic equilibrium, when the equilibrium state is reached, the positive and negative reactions continue.
3 and so on. When the equilibrium state is reached, the positive reaction rate and the reverse reaction rate are equal, but not equal to 0. That is, v is positive =v is negative ≠0.
④ Determination: When the equilibrium state is reached, the concentration of each component remains unchanged and the content of each component remains certain.
⑤ Change: When conditions change, the original balance will be destroyed and a new balance will be established under new conditions.
(3) Marks for judging the state of chemical equilibrium:
①VA (positive direction) =VA (negative direction) or nA (consumption) =nA (generation) (comparison of the same substance in different directions)
(2) The concentration or percentage content of each component remains unchanged.
(3) Judging by color invariance (there is a substance that is colored)
(4) The amount or total volume or total pressure or average relative molecular weight of the total substance remains unchanged (provided that the amount of the total substance of the gas before and after the reaction is not equal, that is, for the reaction).
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