1. Chemistry is a basic science to study the composition, structure, properties and changing laws of matter.
2. Working people in China will make bronzes in Shang Dynasty and steel in Spring and Autumn and Warring States Period.
3. Green chemistry-environment-friendly chemistry (the combination reaction conforms to the green chemical reaction)
① Four characteristics P6 (raw materials, conditions, zero emission, products) ② Core: eliminating pollution from the source by using chemical principles.
4. Candle burning experiment (product names are not allowed to be used when describing phenomena)
(1) Flame: flame core, inner flame (brightest) and outer flame (highest temperature).
(2) Compare the temperature of each flame layer: put a matchstick flat in the flame. Phenomenon: both ends are carbonized first; Conclusion: The external flame temperature is the highest.
(3) H2O to be tested: cover the upper part of the flame with a dry and cold beaker with water mist in it.
CO2: Take off the beaker, pour in the clarified lime water, and shake well to become turbid.
(4) After fire extinguishing: there is white smoke (paraffin vapor). When the white smoke was lit, the candle was rekindled. Explain paraffin steam combustion.
5. Comparison of inhaled air and exhaled air
Conclusion: Compared with inhaled air, the content of O2 in exhaled air decreased, while the content of CO2 and H2O increased.
(Inhaled air and exhaled air have the same composition)
6. An important way to learn chemistry-scientific inquiry
General steps: ask questions → guess and assume → design experiments → experiment verification → record and conclusion → reflection and evaluation.
The characteristics of chemistry learning: paying attention to the essence, change, change process and phenomenon of matter;
7, chemical experiment (chemistry is a science based on experiments)
A, commonly used instruments and methods of use
(1) Instruments for heating-test tubes, beakers, flasks, evaporating dishes and conical bottles.
Instruments that can be directly heated include test tubes, evaporating dishes and burning spoons.
Instruments that can only be heated indirectly are beakers, flasks and conical bottles (padded with asbestos mesh-heated evenly).
Instruments that can be used for solid heating include test tubes and evaporating dishes.
Instruments that can be used for liquid heating include test tubes, beakers, evaporating dishes, flasks and conical bottles.
Non-heatable instruments. Measuring cylinders, funnels, gas cylinders
(2) Measuring container-measuring cylinder
When measuring the volume of liquid, the measuring cylinder must be placed smoothly. The line of sight is flush with the scale line and the lowest point of concave liquid level in the measuring cylinder.
The measuring cylinder cannot be used for heating or as a reaction vessel. The measuring cylinder with the measuring range of 10 ml can generally only read 0. 1 ml.
(3) Scale-pallet scale (used for rough weighing, generally accurate to 0. 1 g). )
Note: (1) Adjust the zero point first.
(2) The position and weight of the weighed object are "left object and right code".
(3) The weighed objects cannot be directly placed on the tray.
When weighing general drugs, put a piece of paper with the same size and quality in each tray on both sides and weigh it on the paper. Wet or corrosive drugs (such as sodium hydroxide) are weighed in covered glassware (such as small beakers and watches).
(4) Clamp the weight with tweezers. When adding weights, add the weights with large mass first, and then add the weights with small mass (first big and then small).
(5) After weighing, the roaming code should be zero. Put the weight back in the weight box.
(4) heating container-alcohol lamp
(1) Pay attention to the "three noes" when using alcohol lamps: ① Do not add alcohol to the burning alcohol lamps; ② Light the alcohol lamp from the side with a match, instead of directly lighting another alcohol lamp with a burning alcohol lamp; (3) Extinguish the alcohol lamp should be extinguished together with the lamp holder, and cannot be blown out.
(2) The amount of alcohol in the alcohol lamp should not exceed 2/3 of the volume of the alcohol lamp and should not be less than 1/4.
(3) The flame of alcohol lamp is divided into three layers: outer flame, inner flame and flame core. Heat an object with the outer flame of an alcohol lamp.
(4) If the alcohol lamp is accidentally knocked over when burning, and alcohol burns on the experimental platform, it should be covered with sand or put out the flame with a wet rag in time, and cannot be washed with water.
(5) Bracket-iron clamp and test tube clamp
The position where the iron clamps the test tube should be near the test tube mouth 1/3. Don't press your thumb on the short handle of the tube clamp.
When the test tube clamps the test tube, the test tube clamp should be erected from the bottom of the test tube; The clamping position is near the tube mouth 1/3; Hold it in your hand.
(6) Instruments for separating substances and adding liquids-funnels and long-necked funnels
When filtering, the nozzle at the lower end of the funnel should be close to the inner wall of the beaker to prevent the filtrate from splashing.
The lower nozzle of the long-necked funnel should be inserted below the liquid level to prevent the generated gas from escaping from the long-necked funnel.
Second, the basic operation of chemical experiment
(a) Access to medicines
1, drug storage:
Generally, solid drugs are put in wide-mouth bottles, and liquid drugs are put in narrow-mouth bottles (a small amount of liquid drugs can be put in drop bottles).
Metal sodium is stored in kerosene and white phosphorus is stored in water.
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2, the general principles of drug access
① Dosage: Take the medicine according to the needs of the experiment. If the dose is not specified, take the minimum amount, and it is advisable to cover the bottom of the test tube with solid.
The suitable liquid is 1~2mL.
Don't put the extra reagent back into the original bottle, don't throw it around, and don't take it out of the laboratory, but put it in the designated container.
② "three noes": you can't take medicine with your hands, taste medicine with your tongue, and smell medicine directly with reagents (if you need to smell the smell of gas, you should gently fan the bottle mouth with your hands, so that only a very small amount of gas can enter your nostrils).
Step 3 Get solid drugs
① Powdered and granular medicine: medicine spoon or V-shaped paper slot ② Block and strip medicine: take it with tweezers.
4. Obtain liquid medicine
(1) Dumping method of liquid reagent:
Take off the bottle cap and pour it on the table (to prevent the medicine from being contaminated). The label should be placed in the center of the hand (to avoid corrosion of the label by residual liquid flow). Pick up the reagent bottle, put the bottle mouth close to the edge of the test tube mouth, slowly inject the reagent, pour it out, cover the bottle cap, put the label outward and put it back.
(2) Liquid reagent drop method:
How to use the dropper: a, first drive out the air in the dropper, and then suck out the reagent.
B, dropping reagent, dropper should be kept vertically hanging above the mouth of the container.
C, in the process of use, always put the rubber nipple on the floor, so as not to be corroded by reagents.
D rinse the dropper with water immediately after use (except the dropper on the dropper bottle).
E, rubber dropper must not extend into the container or contact with the container wall when in use, otherwise it will cause reagent pollution.
(2) Connect the instruments and equipment and check the air tightness of the equipment.
Air tightness inspection of the device: First, immerse one end of the catheter in water, and hold it close to the outer wall of the container by hand, and pause for a moment. If the catheter
When bubbles emerge from the mouth, release the palm of your hand and a water column rises at the mouth of the catheter. After the pause, the water column will not fall back, which means
The device will not leak.
(3) heating of substances
(1) When heating solids, the mouth of the test tube should be slightly inclined downward, and the test tube should be heated evenly first, and then heated in the center.
(2) When heating the liquid, the volume of the liquid should not exceed 1/3 of the volume of the test tube. When heating, make the test tube form an angle of about 450 with the desktop. When heating, heat the test tube evenly first, then heat the middle and lower part of the liquid in the test tube, and move the test tube up and down from time to time. To avoid injury, do not point the test tube mouth at yourself or others when heating.
(IV) Precautions for filtration operation: "One stick, two lows and three inclines"
"One paste": the filter paper clings to the inner wall of the funnel.
"Two lows": (1) The filter paper edge is lower than the funnel mouth (2) The liquid level in the funnel is lower than the filter paper edge.
"Triclinic": (1) The nozzle at the lower end of the funnel is close to the inner wall of the beaker.
(2) When the glass rod is used for drainage, the lower end of the glass rod gently leans against one side of the three-layer filter paper.
(3) When the glass rod is used for drainage, the mouth of the beaker is close to the middle of the glass rod.
The possible reasons why the filtrate is still turbid after filtration are:
① The beaker containing the filtrate is not clean ② The liquid level is higher than the edge of the filter paper when pouring the liquid ③ The filter paper is damaged.
(5) Precautions for evaporation: (1) During the heating process, the glass rod is continuously stirred.
(Function: accelerate evaporation and prevent droplets from splashing due to local overheating)
(2) Stop heating when the liquid is close to evaporation (or a large number of solids appear), and use the waste heat to evaporate the remaining water.
Hair, so as to avoid solid being splashed by heat.
(3) The hot evaporating dish should be clamped with a crucible clamp. If the hot evaporating dish needs to be put on the experimental platform immediately, it should be padded with stones.
Cotton net.
(6) Cleaning of instruments:
(1) Waste residue and liquid are poured into the waste tank, and useful substances are poured into the designated container.
(2) Standard for cleaning glass instruments: Water attached to glass instruments neither gathers into water drops nor flows down in strands.
(3) Grease adhesion on the glass instrument: firstly, clean it with hot sodium carbonate (Na2CO3) solution or washing powder, and then rinse it with clean water.
(4) The glass instrument is attached with water-insoluble alkali, basic oxide and carbonate: it is dissolved with dilute hydrochloric acid first, and then washed with water.
(5) After washing the instrument, it should not be misplaced. After the test tube is washed, it should be inserted upside down in the test tube rack to dry.
Unit 2 "The air around us"
1, the first chemist to explore the composition of air: lavoisier (the first one to make quantitative analysis with a balance).
2. Composition and composition of air
Air component O2 N2 CO2 rare gas other gases and impurities
Volume fraction 2 1% 78% 0.03% 0.94% 0.03%
(1) determination of oxygen content in air
Combustible requirements: sufficient quantity; solid products: red phosphorus.
Equipment requirements: good air tightness.
C. Phenomenon: a large amount of white smoke is produced, and the liquid level in the tank rises by about 1/5 volume.
D. conclusion: air is a mixture; O2 accounts for about 1/5, which can support combustion;
N2 accounts for about 4/5, which does not support combustion, nor can it burn, and is insoluble in water.
E. inquiry: ① liquid level rise is less than 1/5. Cause: Air leakage, insufficient red phosphorus and incomplete cooling.
② Can iron and aluminum be used instead of red phosphorus? There is no reason: iron and aluminum can't burn in air.
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Can carbon and sulfur replace red phosphorus? No reason: the product is gas, and it can't produce pressure difference.
(2) Air pollution and prevention: The main pollutants that pollute the air are harmful gases (CO, SO2, nitrogen oxides) and smoke. At present, the items included in the air pollution index include CO, SO2, NO2, O3 and inhalable particles.
(3) Harm and protection of air pollution:
Hazards: seriously damaging human health, affecting crop growth, destroying ecological balance, global warming, ozone layer destruction, acid rain, etc.
Protection: strengthen air quality monitoring, improve environmental conditions, use clean energy, and plant trees, trees and grass actively after the waste gas from the factory is treated.
(4) Current environmental pollution problems:
Ozone layer destruction (Freon, nitrogen oxides, etc. ) and greenhouse effect (carbon dioxide, methane, etc. )
Acid rain (NO2, SO2, etc. ) and white pollution (plastic waste, etc. )
6. Oxygen
(1) Chemical properties of oxygen: unique properties: supporting combustion and supplying breathing.
(2) the reaction of oxygen with the following substances
Material phenomenon
Carbon stays red-hot in the air and emits white light in oxygen, and the generated gas makes the clear limewater turbid.
Phosphorus produces a lot of white smoke.
Sulfur gives off a faint light blue flame in the air and a bright blue-purple flame in oxygen.
Produce a gas with a pungent smell.
Magnesium gives off dazzling white light, giving off heat and producing white solid.
aluminium (Al)
Iron burns violently, and sparks are everywhere, producing black solid (Fe3O4).
Paraffin wax burns in oxygen to give off white light, and water droplets are generated on the bottle wall, resulting in gas that makes clear limewater turbid.
* When burning iron and aluminum, put a small amount of water or fine sand at the bottom of the gas container to prevent the overflowing high-temperature melt from cracking the bottom of the bottle.
* Iron and aluminum are nonflammable in air.
(3) Preparation of oxygen:
Industrial oxygen production-method of separating liquid air (principle: different physical changes of boiling points of nitrogen and oxygen)
Principle of oxygen production in laboratory: 2h2o 2mno22h2o+O2 =
2k MnO 4△k2mno 4+MnO 2+O2↓
2KClO3MnO22KCl+3O2↑
(4) Selection of gas taking and gathering devices△
Generating devices: solid-solid heating type and solid-liquid unheated type collecting devices: according to the density and solubility of substances,
(5) Operation steps and matters needing attention in oxygen production (taking potassium permanganate oxygen production and drainage collection as an example)
A. Steps: check-install-set point-receive-move-extinguish
Listen
① The test tube mouth is slightly inclined downward: to prevent the test tube from being broken due to the backflow of condensed water.
② Spread the medicine on the bottom of the test tube: heat it evenly.
③ The distance between the iron clip and the nozzle is about 1/3.
④ The catheter should be slightly exposed from the rubber plug: it is convenient for gas discharge.
⑤ Put a ball of cotton at the mouth of the test tube to prevent potassium permanganate powder from entering the catheter.
⑥ When collecting by drainage method, collect when bubbles emerge uniformly and continuously (air in the test tube is discharged first).
⑦ At the end of the experiment, move the catheter first, and then put out the alcohol lamp: to prevent the test tube from breaking when pouring water.
When collecting gas by exhausting air, the duct extends to the bottom of the gas container.
(6) Oxygenation: put a piece of wood with Mars at the mouth of the gas container.
Inspection: Stick the wooden strips with sparks in the gas container.
7. catalyst: It can change the chemical reaction rate of other substances, as well as its own quality and chemistry.
A substance whose properties have not changed before and after the reaction. (One change and two unchanged)
The role of catalysts in chemical reactions is called catalysis.
8, the use of commonly used gas:
① Oxygen: used for breathing (such as diving and medical emergency).
Support combustion (such as fuel combustion, steelmaking, gas welding)
② Nitrogen: inert protective gas (chemically inert), important raw materials (nitric acid, fertilizer) and liquid nitrogen freezing.
(3) Rare gases (helium, neon, argon, krypton, xenon, etc.):
Protective gas, electric light source (which emits different colors when electrified) and laser technology.
9, common gas inspection methods
(1) oxygen: wooden strips with Mars.
② Carbon dioxide: clarified limewater.
(3) Hydrogen: ignite the gas and cover it above the flame with a dry and cold beaker;
Alternatively, hot copper oxide is passed first and then anhydrous copper sulfate is passed.
9. Oxidation reaction: chemical reaction between substance and oxygen (oxygen element).
Violent oxidation: combustion
Slow oxidation: rust, human breath, food decay, wine making.
* * * Similarity: ① Both are oxidation reactions ② Both are exothermic reactions.
Unit 3 Understanding Water in Nature
I. Water
1, composition of water:
(1) water electrolysis experiment
A. Device-water electrolyzer
B. Power supply type-DC
C. The purpose of adding sulfuric acid or sodium hydroxide is to enhance the conductivity of water.
D. chemical reaction: 2h2o = = 2h2 =+O2 =
Generation position negative electrode positive electrode
Floor area ratio 2: 1
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Mass ratio 1: 8
F. Inspection: O2—— Put a wooden strip with sparks at the air outlet —— The wooden strip is re-ignited.
H2-the air outlet is equipped with a burning wood-the gas burns to produce a light blue flame.
(2) Conclusion: ① Water is composed of hydrogen and oxygen.
② A water molecule consists of two hydrogen atoms and 1 oxygen atom.
(3) In chemical changes, molecules can be separated, but atoms cannot be separated.
According to the chemical formula H2O of water, what information can you read?
The meaning of chemical formula H2O
(1) said a substance water this substance.
(2) indicates the composition of the substance. Water consists of hydrogen and oxygen.
(3) A molecule representing this substance, a water molecule.
(4) indicates the molecular composition of the substance. A water molecule consists of two hydrogen atoms and one oxygen atom.
2. Chemical properties of water
(1) charged decomposition 2H2O = = = 2H2 =+O2 =
(2) Water can react with some oxides to generate alkali (soluble alkali), such as H2O+CaO==Ca(OH)2.
(3) Water can react with some oxides to generate acids, such as H2O+CO2==H2CO3.
3. Water pollution:
(1) water resources
A. 7 1% of the earth's surface is covered with water, but less than 1% of fresh water is available for human use.
B.the ocean is the largest reservoir on the earth. Seawater contains more than 80 elements. The most abundant substance in seawater is H2O, the most metal element is sodium, and the most element is oxygen. ..
C. The distribution of water resources in China is uneven, and the per capita possession is small.
(2) Water pollution
A water pollutants: industrial "three wastes" (waste residue, waste liquid and waste gas); Unreasonable use of pesticides and fertilizers
Discharging domestic sewage at will
B, prevent water pollution: industrial waste should be treated and discharged up to standard, and zero discharge should be advocated; Domestic sewage should be treated centrally to meet emission standards and advocate zero discharge; Rational use of pesticides and fertilizers, advocate the use of farmyard manure; Strengthen water quality monitoring.
(3) Care for water resources: save water and prevent water pollution.
4. Purification of water
(1) The purification effect of water from low to high is standing, adsorption, filtration and distillation (all physical methods), and the operation with the best purification effect is
Distillation; The water purifying agent with filtration and adsorption functions is activated carbon.
(2) Hard water and soft water A. Definition Hard water is water containing more soluble calcium and magnesium compounds;
Soft water is water containing no or little soluble calcium and magnesium compounds.
B identification method: soapy water, hard water with scum or less foam, and soft water with more foam.
C. methods of softening hard water: distillation and boiling.
D. Disadvantages of long-term use of hard water: waste of soap and inability to clean clothes; Boilers are easy to scale, which not only wastes fuel, but also easily deforms pipelines and even causes boiler explosion.
5. Others
(1) water is the most common solvent and the oxide with the smallest relative molecular weight.
(2) Water inspection: anhydrous copper sulfate, if it changes from white to blue, indicates the existence of water; Copper sulfate +5H2O = copper sulfate? 5H2O
Water absorption: commonly used concentrated sulfuric acid, quicklime, solid sodium hydroxide and iron powder.
Second, hydrogen H2
1, physical property: the gas with the lowest density (downward exhaust method); Insoluble in water (drainage method)
2, chemical properties:
(1) combustibility (application: high-energy fuel; Hydrogen and oxygen flame welding, cutting metal)
2H2+O2 = = = 2H2O Before ignition, measure the purity (method? )
Phenomenon: emit light blue flame, release heat and produce water droplets.
(2) Reducibility (use: smelting metal)
H2+CuO = = Cu+H2O Hydrogen "Go out early and return late"
Phenomenon: black powder turns red, and water droplets form at the mouth of the test tube.
(Summary: combustible and reducing substances H2, carbon and carbon monoxide)
3. Laboratory method of hydrogen.
Principle: Zn+H2SO4 = ZnSO4+H2 ↑ Zn+2hcl = ZnCl2+H2 ↑.
The reason why concentrated hydrochloric acid cannot be used is that concentrated hydrochloric acid is highly volatile;
The reason why concentrated sulfuric acid or nitric acid cannot be used is that concentrated sulfuric acid and nitric acid have strong oxidizing properties.
4. Hydrogen energy has three advantages: no pollution, high heat release and wide sources.
Three, molecules and atoms
Molecular atom
Definition: Molecules are particles that keep the smallest chemical properties of substances, and atoms are the smallest particles in chemical changes.
Small volume and mass; Move on; Have a gap
Connecting molecules are composed of atoms. Molecules and atoms are particles that make up matter.
In differential chemical changes, molecules can be separated and atoms cannot be separated.
The essence of chemical reaction: in chemical reaction, molecules split into atoms and atoms recombine into new molecules.
Four. Composition, composition and classification of substances
Composition: A substance (pure substance) consists of elements.
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Atoms: metals, rare gases, carbon, silicon, etc.
Substances constitute molecules: for example, hydrogen chloride is composed of hydrogen chloride molecules. H2、O2、N2、Cl2 .
Ions: NaCl plasma compounds, such as sodium chloride, consist of sodium ions (Na+) and chloride ions (Cl-).
Mixture (multiple substances)
Classification simple materials: metal, nonmetal and rare gas.
Purity (an element)
Compounds: organic compounds CH4, C2H5OH, C6H 12O6, starch, protein (multi-elements).
Oxide H2O, copper oxide and carbon dioxide
Inorganic compound acid hydrochloric acid sulfuric acid nitric acid
Alkali NaOH Ca(OH)2 KOH
Salt NaCl CuSO4 Na2CO3
Unit 4 The Mystery of Material Composition Review Study Plan
1, composition of atoms
Understanding of (1) Atomic Structure Diagram
(2) The number of nuclear charges in an atom = the number of protons = the number of electrons outside the nucleus determines the number of protons (nuclear charges) in an element.
(3) The mass of atoms is mainly concentrated on the nucleus. (4) The outermost electron number that determines the chemical properties of an element.
(4) The relative atomic mass ≈ proton number+neutron number determines the atomic mass of the nucleus.
Note: tHe chemical properties of the outermost layer are not necessarily the same as the same number of electrons (Mg, he outermost electron number is 2)
The chemical properties of the outermost layer may be similar, but the number of electrons is different (he and Ne are both stable structures).
2. Elements
(1) Definition: The general term for a class of atoms with the same nuclear charge number (proton number).
The essential difference between one element and another is that the number of protons is different.
note:
* A substance composed of the same element is not necessarily a simple substance, such as a mixture of O2 and O3 or a mixture of diamond and graphite, and cannot be a compound.
(2) Representation method-element symbol-Latin initials capitalized
First, the writing method:
B, meaning
Note: * Some element symbols can also represent simple substances, such as iron, helium, carbon and silicon.
* Adding a number before an element symbol can only have a microscopic meaning, not a macroscopic meaning. For example, 3O means only three oxygen atoms.
C. periodic table of elements
* Discovery: Mendeleev
* Arrangement basis
* Note: Atomic number = number of protons.
D, classification
E, most elements: crust: O, Si, Al, Fe cells: O, C, H.
3. Ions: charged atoms or atomic groups.
(1) indicates the method and significance: for example, Fe3+: an iron ion has a positive charge of 3 units.
(2) Understand the schematic diagram of ion structure
Note: Different from the schematic diagram of atoms, the number of protons = the number of electrons is the schematic diagram of atomic structure.
* number of atoms ≠ number of electrons is the schematic diagram of ion structure.
(3) Differences and connections with atoms
Particle type proton ion
Cationic anion
administrative region
Proton number of other particle structures = electron number proton number >; Electron number proton number
Particles are not electric, they are positive and negative.
Symbols are represented by element symbols, cation symbols and anion symbols.
Second, the appearance of material composition:
1, valence
A, writing and meaning: the valence of Mg: magnesium is+2; The valence of magnesium in magnesium chloride is +2.
B, the meaning of several numbers
Fe2+ Each ferrous ion has two unit positive charges: 3Fe2+:3 ferrous ion.
2H2O is two water molecules, each containing two hydrogen atoms.
C, the algebraic sum of the positive and negative valence of each element in the compound is zero.
D, valence is the nature of the atoms of elements when they form compounds, so the valence of elements in simple molecules is 0.
2. Chemical formula
(1) Writing:
A simple substance: metals, rare gases and most solid nonmetals are usually represented by elemental symbols; The molecules of nonmetallic gases such as oxygen, hydrogen, nitrogen and chlorine are composed of two atoms, and their chemical formulas are O2, H2, N2 and Cl2.
.
Compound B: The positive valence comes first and the negative valence comes last (except NH3 and CH4).
(2) Meaning: For example, the meaning of chemical formula H2O is 4 points, and the meaning of chemical formula Fe is 3 points.
(3) Calculation:
A, calculate the relative molecular mass = the relative atomic mass of each element × the sum of the number of atoms
B, calculate the mass ratio of the constituent elements of the substance: the ratio of relative atomic mass × atomic number.
C, calculating the mass fraction of elements in the substance.
It is best to listen to the teacher write his own notes.
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