Lecture 1: Entering the Chemical World 1. What is chemistry? 2. How to learn chemistry? ① Methods of learning chemistry: experimental exploration; ② The tools for learning chemistry are: periodic table of elements; The characteristics of chemistry learning are: three concerns (about the composition, nature and changing law of substances) 3 basic skills of chemistry experiment: ① contact with drugs. Powder solid, medicine spoon or paper trough; Block solid, tweezers; A small amount of liquid, dropper; A certain amount of liquid, measuring cylinder or dropper; The amount is not specified in the experiment, and the minimum amount is generally used; Liquid 1-2 ml, and solid covers the bottom of the test tube. (2) heating of substances. The commonly used heating appliance is alcohol lamp (the wick should be cut flat, the wine should not be put on the shoulder, and the temperature of the inner flame is low. When turning off the light, use a cap, and mouth blowing is the most taboo). Heat the solid material (the test tube is fixed with an iron frame, and the iron clip is one-third away from the mouth. The mouth of the heated test tube is inclined downward to avoid cracking of the reflux tube. The solid is laid flat near the bottom of the tube, and the moving flame is heated evenly. After use, cool it and then remove it. Don't worry if it is clean and stable). Heat the liquid substance (the liquid content is less than one third, the outer wall should be dry to prevent burning and cracking, the handle should be supported by a wooden clamp tube, the liquid level and bottom should be heated evenly, and the nozzle should face the air, not the person). ③ Cleaning of instruments (glass instruments). Standard: The inner wall is attached with a uniform water film, which will not agglomerate or flow down in strands. Methods: Use a brush, rinse with detergent and water. Special oil stain: wash with water-insoluble alkali, metal oxide and carbonate, dilute hydrochloric acid, manganese dioxide and potassium permanganate, concentrated hydrochloric acid and hot alkali such as sodium carbonate. ④ Gas collection. Drainage method is suitable for gases that are insoluble in water or insoluble in water and do not react with water. Upward exhaust method is suitable for gases with higher gas density than air. Downward exhaust method is suitable for gases with lower gas density than air. 1. Do you think the following options are beyond the scope of chemical research: (C) A, composition and structure of substances B, changes and properties of substances C, motion state D, uses and preparation of substances 2. The following are the physical changes: (C) A, rice changed into wine B, kitchen knife rusted C, wet clothes dried, food deteriorated 3, drugs left over from the chemistry laboratory, and the correct treatment methods are (B) A, take them home B, pour them into the designated container C, pour them into the sink D at will, and pour them back to the original reagent bottle. 4. When selecting the collection method of gas preparation in the laboratory, the following properties can be ignored: (A) A, color B, density C, solubility D, and whether it reacts with water. 5. There are the following records in the laboratory report. Among them, the experimental data are reasonable: (a) A. Weigh1/kloc-0.7 g copper oxide powder B with a tray balance, measure 5.26 ml sulfuric acid solution C with a 100 ml measuring cylinder, and measure the ph value of the solution with a wide range ph test paper. The temperature displayed on the thermometer is 25.68℃6. NO is a gas that is insoluble at room temperature. To collect a bottle of dead air now, the collection methods that should be adopted are (A) A, drainage only method b, upward ventilation method c, drainage method or upward ventilation method d and downward ventilation method 7. In the following experimental operation, the mistake is (c) a. Before preparing carbon dioxide gas, check the air tightness of the device B. Before igniting oxygen, check the purity of chlorine gas C. Blow out the flame D of alcohol lamp with your mouth. Before burning iron wire in oxygen, add a small amount of fine sand to the bottom of the gas container. 8. Clean the following glassware, which is correct. (ad) A. Clean the oil stain in the test tube with hot soda solution first, and then rinse it with clear water. B, first pour the waste liquid in the test tube into the sewer, then rinse the test tube with clear water and dissolve it with caustic soda solution first. Rinse with clean water. Wash the beaker containing lime water with dilute hydrochloric acid first, and then rinse it with clear water. 9. The following instruments can be used for dissolving solids, preparing solutions and heating more reagents: (B) A, conical flask B, beaker C, measuring cylinder D, test tube 10. Dropping copper sulfate solution into a test tube filled with sodium hydroxide solution, a blue solid was observed. 1 1. Through experimental research, the content of exhaled gas has changed obviously compared with inhaled gas, mainly in three substances: oxygen, carbon dioxide and water vapor. 12. Put the beaker forward, cover it with a glass sheet, and collect colorless and nontoxic gas in the beaker. The knowledge learned is used to explore and determine what gas may be. A: It is known that the specific gravity of this gas is greater than that of air, and it is colorless and nontoxic. From the hypothesis, verification methods, possible phenomena and conclusions to explore. It may be carbon dioxide gas. Pour in clarified lime water for verification. If limewater becomes turbid, then the gas is carbon dioxide. It may also be oxygen, and the wooden strips with mars verify this. If the wood is rekindled, then the gas is oxygen. 13. Burning candles in the air will produce water and carbon dioxide, which will be introduced into a flask with candles and then into clear lime water. The phenomenon seen in the above experiment is that the candle goes out and the clarified lime water becomes turbid. Therefore, the chemical nature of carbon dioxide is that carbon dioxide can neither burn nor support combustion, and carbon dioxide can react with clear limewater. 14. Invert a large test tube filled with sulfur dioxide in the sink, and the water level in the test tube rises above the water level in the sink. What nature can you draw from it? A: Sulfur dioxide is soluble in water (or can react with water). (1) Design experiment to prove the acidity and alkalinity of the liquid in the test tube? (block the nozzle with your thumb, remove it from the water surface, drop the purple litmus test solution into the test tube or measure the pH value with pH test paper. From this experiment, can you think of which gas sulfur dioxide is similar to what we have learned? Try to write a similar chemical equation. (Carbon dioxide reacts with water or sodium hydroxide, H2O+SO2 = H2SO4)