Unit 1 "Entering the Chemical World" Knowledge Points
1. Chemistry is a basic science to study the composition, structure, properties and changing laws of matter.
2. The Shang Dynasty in China made bronzes, and the Spring and Autumn Period and the Warring States Period made steel.
3. Green chemistry-environment-friendly chemistry (the combination reaction conforms to the green chemical reaction)
① Four characteristics of P6 (raw materials, conditions, zero emission and products)
② Core: Using chemical principles to eliminate pollution from the source.
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) Inspection of products
H2O: Cover the upper part of the flame with a dry and cold beaker, which contains water mist.
CO2: Take off the beaker, pour in the clarified lime water, and shake well to become turbid.
(4) After extinguishing: there is white smoke (paraffin vapor). When the white smoke is lit, the candle will be rekindled.
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: (2) The position for weighing objects and weights is "left object and right code". In case of misoperation: if it is a left-handed object, medicine = weight-travel 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.
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.
Excess reagents should not be put back into the original bottle, nor should they be thrown away or taken out of the laboratory, but should be placed in another clean 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 drugs: medicine spoon or V-shaped paper slot.
② Blocks and strips of drugs: take them out with tweezers.
4. Obtain liquid medicine
① Dumping method of liquid reagent: Take off the bottle cap and pour it on the table (to avoid drug contamination). 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:
Use of dropper: A, B, when dropping reagent, the dropper should be hung vertically above the mouth of the container for dropping.
(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, hold it close to the outer wall of the container by hand, and stop for a moment. If there are bubbles coming out of the catheter mouth, release your hand and a water column will rise at the catheter mouth. After the pause, the water column did not fall back, indicating that the device did 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 shall 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"
Key points of filtering operation: "one paste", "two lows" and "three leanings"
"One paste" means that the filter paper soaked with water should be close to the funnel wall;
"Two lows" means that ① the filter paper edge is slightly lower than the funnel edge ② the filtrate level is slightly lower than the filter paper edge;
"Three leanings" means ① the beaker clings to the glass rod, ② the glass rod clings to the edge of the three layers of filter paper, and ③ the end of the funnel clings to the inner wall of the beaker.
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.
To prevent solids from splashing out due to 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 asbestos 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) Water-insoluble alkali, basic oxide and carbonate are attached to the glass instrument: they are first dissolved with dilute hydrochloric acid 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
atmospheric composition
oxygen
N2
carbon dioxide
rare gas
Other gases and impurities
Volume fraction
2 1% is about 1/5.
78%, about 4/5
0.03%
0.94%
0.03%
(1) Determination of oxygen content in air
Flammability requirements: sufficient solid products.
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. Can carbon and sulfur replace red phosphorus? No reason: the product is gas, and it can't produce pressure difference.
(2) Main air pollutants: NO2, CO, SO2 and O3 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.
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
phosphorus (P)
Produce a lot of white smoke
iron
Burning violently, sparks are everywhere, and black solid (Fe3O4) is generated.
* 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.
(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: summarized as: inspection, installation, clicking, clicking, receiving, moving and extinguishing harmony: the teahouse collects interest at a fixed point.
Listen
① The mouth of the test tube is slightly inclined downwards: to prevent the test tube from being broken due to the backflow of condensed water; (2) spreading the medicine on the bottom of the test tube: heating evenly; ③ The distance between the iron clip and the test tube mouth is about1/3; ④ The rubber plug should be slightly exposed from the catheter: it is convenient for gas discharge; ⑤ Put a ball of cotton at the mouth of the test tube: prevent potassium permanganate powder from entering the catheter; ⑤ When collecting by drainage method, collect when bubbles emerge uniformly and continuously (when the air in the test tube begins to be exhausted, move the catheter first, and then turn off the alcohol lamp: to prevent the test tube from breaking due to backward irrigation. 8 When collecting gas through exhaust, the conduit extends to the bottom of the gas container. (6) Oxygen inspection: put a piece of wood with sparks at the mouth of the gas container.
Inspection: Stick the wooden strips with sparks in the gas container.
7. Catalyst: A substance that can change the chemical reaction rate of other substances in a chemical reaction, but its own quality and chemical 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: sparks; ② Carbon dioxide: clarified limewater; ③ Hydrogen: ignite the gas and cover it with a dry and cold beaker above the flame;
Alternatively, hot copper oxide is passed first and then anhydrous copper sulfate is passed.
9. Oxidation reaction: the reaction between a substance and oxygen (oxygen element).
Violent oxidation: combustion
Slow oxidation: rust, human breath, food decay, wine making.
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.
The purpose of adding sulfuric acid or sodium hydroxide is to improve the conductivity of water.
Charge