Physical changes do not produce new substances. Shape change (broken glass, etc.). ) and state (sublimation of dry ice, freezing of water, etc. )
Chemical changes produce new substances. The catalyst can change the chemical reaction rate, and its quality and chemical properties remain unchanged before and after the reaction.
Common combustion phenomena: C- white light, S- blue-purple flame (in oxygen), P- white smoke, Fe- Mars, Al- dazzling white light,
Mg- dazzling white light, H2- light blue flame, Co- blue flame, CH4-- blue flame.
Both give off heat.
Bubbles-gases such as oxygen, H2 and carbon dioxide are generated in the solution;
Precipitation -CaCO3
Solution discoloration-the formation or disappearance of solutions containing Cu2++, Fe2 ++ and Fe3+; Litmus and phenolphthalein meet with acid-base solution.
Physical properties Color, state, taste, melting point, boiling point, hardness, density, solubility, volatility, conductivity (heat) and ductility.
Chemical properties: flammability, combustion-supporting, stability, activity, oxidation, reduction, acidity, alkalinity, toxicity, corrosiveness,
Substance classification mixture (multiple substances), pure substance (one substance), simple substance (one element), compound (multiple elements), oxide (binary essential oxygen), acid (h++ acid radical ion), alkali (metal ion ++OH-), salt (metal ion+acid radical ion), organic compound (containing carbon) and inorganic.
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Macro-law: the mass of matter is conserved, and the total mass of matter remains unchanged; Element mass is conserved, and element mass remains unchanged.
Microscopy: The species, quantity and mass of atoms remain unchanged.
Objective: to determine the chemical formula [micro] and material [macro] according to the method;
Valence principle: the valence of elements in simple substance is 0. The algebraic sum of the valence of elements in a compound is 0. Determine the valence
The meaning of chemical formula: the elemental composition and categories of substances (organic and inorganic); What atoms are molecules made of? Simple calculation-relative molecular mass, total number of atoms in the molecule, atomic number ratio, element mass ratio, element mass fraction.
Combustible substances for burning and extinguishing (1); (2) oxygen (air); (3) The temperature reaches the ignition point. Satisfy at the same time: burning [lack of one: fire extinguishing]
environment
Protect harmful gases (CO, SO2, NO2) emitted by air-coal and oil combustion, factory exhaust gas, smog and automobile exhaust;
The "three wastes" in aquaculture are discharged at will, and the use of pesticides and fertilizers is unreasonable; Discharging domestic sewage at will;
Greenhouse effect-the content of carbon dioxide and other gases in the air is too high; Acid rain-SO2 and NO2 gases are dissolved in rainwater; .
Harmful substances such as carbon monoxide (combined with hemoglobin), formaldehyde (protein denaturation), aflatoxin and sodium nitrite; Mercury.
In the atom (1), the number of nuclear charges = the number of protons = the number of extranuclear electrons; ⑵ Relative atomic weight = proton number+neutron number.
The acid soil is improved with hydrated lime [calcium hydroxide: Ca (OH) 2].
Iron rusts (1) iron (2) oxygen (3) water. Completely satisfied: rust [one item is missing: rust prevention-dry, clean, oily, painted, plated with metal and alloy]
How many calcium and magnesium compounds do hard water and soft water contain? Difference: soapy water, foam is mostly soft water. Hard water softening: boiling (distillation).
Solution heat phenomenon: concentrated sulfuric acid, quicklime and sodium hydroxide (solid) release heat (temperature rise) when they meet water. Ammonium nitrate (NH4NO3) absorbs heat (temperature drop) when it meets water.
Degreasing detergent-emulsification [small droplets dispersed in water]. Gasoline dissolved. Sodium hydroxide-reaction. Different principles
Basic operation of solid block tweezers and powder spoon. Wipe after use
Liquid-large quantity: pour [bottle stopper upside down, label up, bottle mouth closed, test tube tilted];
Small amount: rubber-tipped dropper (hanging, hanging); Very small amount: glass rod dipped.
Tray balance-set to zero, put paper NaOH beaker], and code left and right. [accurate to 0. 1g]
Measuring cylinder-put it flat, and the line of sight is flush with the lowest point of concave liquid level. Specification selection [accurate to 0. 1 ml]
Alcohol lamp-fire prevention [alcohol content ≤2/3 volume, ignition and fire extinguishing methods, treatment of overflow combustion].
Heating-direct heating: preheat first. Indirect heating: padded with asbestos mesh.
Filtration-filter paper clings to the funnel wall, the edge of filter paper is lower than the funnel mouth, the liquid level is lower than the edge of filter paper, the beaker mouth is close to the glass rod, the end of the glass rod is close to one side of the three-layer filter paper, and the nozzle at the lower end of the funnel is close to the inner wall of the beaker.
Evaporation-evaporating dish, stir with a glass rod to prevent droplets from splashing due to excessive local temperature. When more solids are precipitated and evaporated by waste heat, stop heating. Crystallization-depending on the influence of temperature on solubility, crystals with large cooling and crystals with small evaporation are affected.
Characteristics of solution-homogeneous and stable, (mixture). Solute-solid, liquid and gas. Solvent-water, alcohol, gasoline. tincture of iodine
The solution is divided into a certain temperature and a certain amount of solvent. The insoluble solute in the solution is a saturated solution, otherwise it is an unsaturated solution.
Transformation: saturated → unsaturated-adding water to raise the temperature; Unsaturation → saturation-adding solute, evaporating solvent and cooling.
Solution preparation (1) calculation (2) Weigh [balance, medicine spoon] [measuring cylinder, dropper] (3) Dissolve [beaker, glass rod] (4) Bottle label.
Metal wok-thermal conductivity, wire-conductivity, copper wire-ductility, aluminum foil-(ductility), ...
The use of a substance: the nature determines the use
Diamonds: hard bits, scraping glass. Graphite: soft pencil lead, sliding lubricant, conductive electrode.
Volume fraction of oxygen (supporting combustion and breathing, but spoiling food) and air: 2 1%, accounting for about 1/5 volume.
Hydrogen (low density-balloon, combustible-ideal high-energy fuel, zero pollution, reducibility-smelting metal)
Nitrogen (inactive-food preservation) and air volume fraction: 78%, accounting for about 4/5 of the volume.
Phosphorus (determination method of oxygen content in solid-air after combustion; Combustion produces a lot of white smoke-smoke screen),
Rare gas (very inert-food preservation and protection gas; Electrified light-neon light), volume fraction in air: 0.94%
Iron (thermal conductivity-iron pot; Reaction with hydrochloric acid-iron supplementation for human body; When it meets water and oxygen, it will rust-"double water absorption": the quality of food is guaranteed, and the iron alloy made of it can resist corrosion-stainless steel, and its strength and hardness are also enhanced. Ferroalloys include pig iron and steel-different carbon content).
Aluminum (the most abundant metal element in the earth's crust; Compact oxide film Al2O3-low density, corrosion resistance-aluminum alloy doors and windows),
Carbon dioxide (non-combustible, non-combustion-supporting, density greater than air fire extinguishing; Soluble in water, can react with water and soda; Dry ice sublimation absorbs heat-refrigeration, artificial rainfall and fog; Turbidity of limewater; Photosynthesis (greenhouse gas fertilizer), air volume fraction: 0.03%
Carbon monoxide (combustible gas fuel; Reduction-smelting metal: ironmaking. Toxicity-combined with hemoglobin makes people lack oxygen)
Calcium oxide (reacts with calcium hydroxide for making water; React with water desiccant)
Hydrochloric acid (reacting with metal oxide-derusting; Stomach acid-helps digestion),
Sulfuric acid (reacting with metal oxide-derusting; Concentrated sulfuric acid absorbs water-desiccant),
Sodium hydroxide (absorbent-desiccant; Reacting with carbon dioxide-removing carbon dioxide; React with oil stain-remove oil stain),
Calcium hydroxide (lime water-test carbon dioxide; Reaction with acid-improving acidic soil; Reacting with sodium carbonate to prepare sodium hydroxide; Pesticide bordeaux mixture-mixed with copper sulfate; Pesticide stone sulfur mixture-mixed with sulfur),
Sodium chloride (seasoning, antisepsis, seed selection, snow melting, medical treatment),
Calcium carbonate (limestone or marble reacts with hydrochloric acid to produce carbon dioxide in the laboratory; Decomposition of limestone at high temperature-industrial production of carbon dioxide and quicklime; Marble decoration; Calcium carbonate-calcium supplement),
Sodium carbonate (steamed bread-deacidification and softening; Alkaline degreasing),
Sodium bicarbonate (the main component of baking powder; React with hydrochloric acid-treat hyperacidity).
Energy supply in protein: animal protein-fish, eggs, meat ... Plant protein-soybean, peanut; Enzyme: biocatalyst
The main energy-supplying substance of sugar body: rice flour-starch; Glucose-the human body can directly absorb it; Sucrose;
Petroleum energy supply and energy storage: animal fat-butter and cream; Vegetable oil-rapeseed oil, peanut oil, soybean oil ...;
Vitamins (no energy supply) vegetables and fruits. Vitamin A deficiency-night blindness, vitamin C deficiency-scurvy;
Inorganic salt (no energy supply) trace element deficiency: iron-anemia; Zinc-growth retardation and dysplasia; Selenium-epidermal keratinization, cancer; Iodine goiter; Fluorine-dental caries. Macro-element deficiency: calcium rickets, osteoporosis and easy fracture;
Water is one of the six nutrients.
Plastic polyethylene plastic can package food, it has a thermoplastic heatable seal; Thermosetting plastic for the handle and plug (seat) of the pot;
chemical symbol
Symbols of elements: carbon, hydrogen, oxygen, magnesium, iron, copper, mercury, ... Meaning: indicates an element; And an atom of the element.
Chemical formula: carbon, oxygen, magnesium, carbon dioxide, calcium oxide, hydrochloric acid, sodium hydroxide, sodium chloride, sodium bicarbonate, copper sulfate, ferrous sulfate and ferric chloride. ...
Meaning: indicates a substance; Constituent elements of matter; A molecule; The composition of molecules.
Ion symbol: note that the valence of the ion symbol and the following is "two similarities and two differences" [a coefficient can be added in front of multiple molecules, atoms or ions]
Valence:
3. Particles and elements: the first four elements in the earth's crust: oxygen -O, silicon -Si, aluminum -Al and iron -Fe.
Molecular and atomic models:-It may be carbon monoxide; —It may be H2 or O2; -carbon dioxide; —H2O .
Properties of particles: * * Similarity: "small", "dynamic" and "intermittent". Explain the essential difference between molecules and atoms: inseparable in transformation
The diffusion of ammonia in the air, the diffusion of magenta in water, the drying of wet clothes (evaporation of water) and the smell of flowers show that molecules are constantly moving; The three-state change of matter, the thermal expansion and cold contraction of an object, and the decrease of the total volume after mixing alcohol with water all indicate that there are gaps between molecules, and the size of the gaps will change.
Atomic structure:
4. Schematic diagram of atom (ion) structure:
In Figure A, the nuclear charge is 1 1, the number of protons is 1 1, the number of electrons is 1, the number of electron layers is 3, and the number of outermost electrons is1.
In figures a to e, a and d belong to the same element. The types of elements are determined by the number of nuclear charges (protons).
The chemical properties of particles are similar to those of C, D and E, and the chemical properties are determined by the number of electrons in the outermost layer.
Belong to the atom is a, b, c; Number of protons = number of extranuclear electrons
Belong to the cation is d; Proton number > extranuclear electron number
Belongs to the anion is e. proton number c; Solubility a > b > c； at 30℃; ……。
Determine the crystallization method: crystallization A [steep rise type]-cooling the hot saturated solution;
Crystallization b[ slow rising type]-evaporation solvent.
Solubility concepts: "certain temperature", "100g solvent", "saturation" and "solute mass"
6. Periodic table box:
In the figure on the right, the element name is phosphorus, the element symbol is p, the proton number (nuclear charge number) is 15, the relative atomic mass is 30.97, and the element category is nonmetal.
The categories of elements are distinguished by different colors in the periodic table, but in practical problems, they can be judged according to the names of elements.
7. Determination and application of metal activity;
Whether (1) metal can react with acid and the severity of the reaction: metal activity z > x > y in the right table. Metal x and acid metal y and acid metal z and acid.
Slow bubble generation (+) No bubble generation (-) Fast bubble generation (++)
⑵ Whether metal can react with salt: In the right table.
Metal activity ① m ≤ n; ② m > n. Metal M and salt solution containing metal N.
① There is no change on the surface of m; ② There is N precipitation on the surface of M.
8. Chemical equation: omitted. Four basic types of reactions: compound reaction [variable one] and decomposition reaction [variable one],
Displacement reaction [single 1+ chemistry 1→ single 2+ chemistry 2] and metathesis reaction [chemistry 1+ chemistry 2→ chemistry 3+ chemistry 4 must exchange components with each other].
9. Energy: coal and oil-polluting the environment. Natural gas-a cleaner fossil fuel. New energy-hydrogen [zero pollution] and so on.
10. Particles in solution: alcohol is soluble in water-alcohol molecules and water molecules. Sodium chloride is soluble in water-sodium ions, chloride ions and water molecules.
Ions that cannot exist: the conditions of displacement reaction
H+ and OH-H2O can be formed when it meets water. acid-base neutralization
Precipitation can be formed after meeting: Ca2 ++ and CO32-CaCO3 ↓;
When gas meets water, it can generate: H+ and CO32-CO2 ↑ and H2O；; ; NH4 ++ and OH-NH3 = and H2O.
3. Gas inspection: When checking the composition of mixed gas, water vapor should be checked first, and then other gases should be checked.
A- anhydrous copper sulfate white → blue-test H2O；; ;
B- copper red → black-check O2; Another: Re-ignite the batten with Martian oxygen.
C- lime water clarification → turbidity-test CO2. [H2 and carbon monoxide can be converted before testing]
4. Gas impurity removal device: when removing various gases, remove other gases first, and finally remove water vapor.
A- anhydrous copper sulfate-removing (absorbing) H2O；; ;
A- anhydrous calcium chloride-removing (absorbing) H2O；; ;
Alkaline lime NaOH and Cao]- remove (absorb) H2O and CO2；; Separate or simultaneously
B- copper oxide-removing carbon monoxide from carbon dioxide; change
Propane-concentrated sulfuric acid-H2O； removal (absorption); ;
C- sodium hydroxide solution-CO2 removal (absorption)
Propane-sodium carbonate or sodium bicarbonate solution-change of HCl removal from CO2
5. Test methods for other simple materials, oxides, acids, alkalis, salts and fibers:
Acidic solution (H+): (1) purple litmus test solution [turns red]; (2) pH test paper; [< 7] [3] Active metals such as zinc and iron [bubbles]
Alkaline solution (OH-): (1) purple litmus test solution [turns blue]; (2) Colorless phenolphthalein test solution [turns red]; (3) ph test paper [> 7]
CO32-or HCO3-:dilute hydrochloric acid and clarified limewater. Hydrochloric acid is added to generate bubbles, and clarified lime water is introduced to make it turbid.
Ammonium salt (NH 4++): When mixed and ground with hydrated lime, it produces irritating ammonia smell.
1. Gas generator: A: solid+solid △ gas;
B: solid+liquid gas at room temperature
2. Collection device: c- drainage method [gas is not easy or insoluble in water];
D- downward exhaust method [gas density is less than air];
E- upward exhaust method [gas density is greater than air].
Identification method of animal fiber, plant fiber and synthetic fiber
★ When burning, animal fibers (wool and silk) smell of burnt feathers; It's plant fiber (cotton, hemp) that doesn't smell of burnt feathers.
★ After burning, squeeze the ash by hand. What is fragile is natural fiber, but what is unbreakable is synthetic fiber.
6. Impurity removal methods of other simple substances, oxides, acids, alkalis and salts:
Example of operation method
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The crude salt was purified by filtration (only insoluble impurities were removed) and the mixture of Na2CO3 (soluble) and CaCO3 (insoluble) was separated.
In the experiment of crystallization and purification of crude salt, NaCl crystals were obtained by evaporation of filtrate-evaporation crystallization.
Separation of mixture of NaCl and KNO _ 3-cooling crystallization: KNO _ 3 precipitation.
The mixture of iron powder and copper powder is separated by magnetic attraction: iron powder is attracted by magnets and copper powder is not attracted.
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Removal of Na2CO3 mixed in NaCl by precipitation method: [adding CaCl2 solution] Na2CO3+CaCl2 = CaCO3 ↓+2 NaCl.
Removing Na2CO3 mixed in NaCl by gasification: adding dilute HCl solution for conversion.
Na2CO3+2HCl=2NaCl+H2O+CO2
NaCl (NH4Cl): [NaOH solution] NH4Cl+NaOH = NaCl+NH3 =+H2O.
Removal of CuSO _ 4 from FeSO _ 4 by replacement method: [adding Fe powder] ]CuSO 4+Fe = FeSO 4+Cu 4+Cu transformation.
A small amount of CO2 mixed in CO is removed by absorption: [NaOH solution] 2 NaOH+CO2 = Na2CO3+H2O.
Co2 (co): [thermal CuO conversion] CuO+co△ Cu+CO2.
Removal of CaCO3 mixed in CaO by heating: [high temperature] CaCO3 high temperature Cao+CO2 ↑ transformation.
8. Study on deterioration of sodium hydroxide;
Make sure it has deteriorated: add enough dilute hydrochloric acid-bubbles appear.
Verification of partial deterioration: after adding enough CaCl2 solution, use litmus (turning blue) or phenolphthalein (turning red) or pH test paper (pH greater than 7).
Removing Na2CO3 produced by metamorphism: after dissolution, add Ca(OH)2 solution dropwise until no precipitate is produced, and then filter and evaporate.
Plants lack nitrogen fertilizer: leaves turn yellow. Lack of phosphate fertilizer: the plant is particularly short. Lack of potassium fertilizer: prone to lodging, with brown edges and tips of leaves.
9. Tail gas treatment device: The reactions with CO generation or participation are as follows:
CO2 and C-black powder disappears; CO and CuO- black turns red; CO and fe2o 3- Red turns black.
Treatment method of CO in tail gas: ignite with alcohol lamp or collect with balloon or collect with drainage method.
10. Electrolyzing water device: after power-on, bubbles appear on the electrode. After a period of time, the volume ratio of gas collected in test tube 1(O2) and test tube 2(H2) is about 1∶2. The mass ratio of negative hydrogen O2 to H2 is 8∶ 1. 〗
Conclusion: Water is composed of hydrogen and oxygen. In chemical reactions, molecules are separable and atoms are inseparable.
1 1. Water purification device and various methods:
Waterworks: water intake, sedimentation, filtration, adsorption, disinfection and water supply.
Alum: colloid → small particle aggregation → large particle precipitation.
Activated carbon: It has adsorption and plays a role in decolorization and deodorization.
Distillation: the highest degree of purification. Distilled water can be regarded as pure water.
Among the above methods of purifying water, only distillation can soften hard water.
12. iron (copper) rust experiment and rust prevention method;
⑴ Explore the rust conditions of iron: A: Fe, O2, H2O；; ; Brazil, H2O；; Carbon: iron, oxygen.
Rust prevention: clean and dry, oil-coated, spray-painted, plated with other metals, baked blue and made into alloy. [resource protection]
12. Simulated ironmaking: After purity inspection [explosion-proof], introduce CO, heat [explosion-proof], stop heating, and continue to introduce CO until cooling. tail gas treatment