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. 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;
5. 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 of the weighed object and weight is "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, liquid drugs are put in narrow-mouth bottles (a small amount of liquid drugs can be put in drop bottles), metal sodium is put in kerosene, and white phosphorus is put in water.
2. General principles of medication ① Dosage: Take the medicine according to the experimental needs. If the dose is not specified, take the minimum amount, cover the solid with the bottom of the test tube, and the 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 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 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:
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, 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"
"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, keep stirring with a glass rod (function: accelerate evaporation and prevent droplets from splashing due to excessive local temperature).
(2) When the liquid is close to evaporation (or a large number of solids appear), stop heating and use the waste heat to evaporate the remaining moisture to prevent the solids from splashing out due to heating.
(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.