"Vaporization and Liquefaction" PPT courseware on changes in the state of matter (Lesson 2: Liquefaction)

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"Vaporization and Liquefaction" PPT courseware on changes in the state of matter (Lesson 2: Liquefaction)

Part One Content: Basic Knowledge Key Points

Knowledge Points Liquefaction

1. In winter, students who wear glasses always have a problem when eating noodles, that is, they can no longer see the noodles while eating. This is because the water vapor in the noodles liquefies when it meets the spectacle lenses (fill in the name of the change of state of matter) and becomes Small droplets of water cling to the spectacle lenses.

2. When the rocket is launched, there is a large pool under the launch pad, allowing high-temperature flames to be sprayed into the water. The moment the rocket takes off, the white "air mass" that appears is formed by the liquefaction of water vapor (fill in the name of the state change of matter). This process requires Release heat (select "endotherm" or "release heat").

3. In order to facilitate the transportation of oxygen, the oxygen should be liquefied. The generally used method is (A)

A. Compress volume B. Increase temperature

C. Lower the temperature D. Increase the volume

4. In summer, when eating popsicles, Xiao Ming found that the popsicles were emitting "white gas". He observed and thought carefully and came to the following conclusions, the correct one of which is (C)

A. “White gas” is formed when ice first melts and then vaporizes. B. “White gas” floats upward.

C. "White gas" is formed by the liquefaction of water vapor in the air. D. The formation process of "white gas" requires heat absorption

Vaporization and liquefaction PPT, Part 2: Comprehensive Capability Improvement

5. In the arid desert, the beetle (shown in the picture) has mastered a unique method of obtaining water. A few hours after sunset, the beetles' body temperature will drop below the surrounding temperature. They will bury their heads in the sand and then turn their backs to the direction of the evening breeze, and the water vapor in the air will liquefy on the beetles' backs (filler) State change name) to form water droplets. The more water droplets gather, they will roll along the arched back and fall into the beetle's mouth.

6. Xiaoxin opened the refrigerator door and found a lot of white mist coming out of the freezer. The white mist was caused by the liquefaction of water vapor outside the refrigerator (optional "inside" or "outside"). When he picked up the wet rag to wipe it, the rag stuck to the side wall. This was because of the phenomenon of "solidification" (the name of the change in the state of matter).

7. The picture shows the working principle diagram of the refrigerator. The working principle of the refrigerator is to use a substance called Freon as a heat "porter" to transport the "heat" in the freezer of the refrigerator to the outside of the refrigerator. Freon is a substance that is easy to both vaporize (liquefy) and liquefy (vaporize) (fill in the names of physical state changes). When working, the electric compressor compresses the Freon vapor and forces it into the condenser of the refrigerator, where the Freon vapor turns into a liquid and releases heat (optional "endothermic" or "exothermic"). This heat is absorbed by the surrounding air. take away. The liquid Freon in the condenser enters the tube in the freezer compartment of the refrigerator through a very thin capillary tube, where it quickly vaporizes and absorbs heat (optional "endothermic" or "exothermic"), causing the temperature in the refrigerator to drop, forming The Freon vapor is pumped away by the compressor, pressed into the condenser, liquefied again and releases the heat brought out from the refrigerator. Freon circulates in this way, and the temperature in the freezer compartment of the refrigerator can be maintained at a very low temperature.

Vaporization and liquefaction PPT, Part 3: Expanding exploration and breakthroughs

10. Please design a small experiment: prove "there is water vapor in the air". Requirements: write down the experimental equipment, experimental process and phenomenon, and briefly explain the phenomenon.

(1) Experimental equipment;

(2) Experimental process and phenomena;

(3)Explanation of phenomenon.

Solution: (1) Experimental equipment: an ice-cold beverage bottle taken out of the refrigerator.

(2) Experimental process and phenomenon: When placed in the air, small water droplets appear on the outer surface of the beverage bottle.

(3) Explanation of the phenomenon: Water vapor in the air liquefies into small water droplets when encountering cold beverage bottles.

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For more information about the PPT courseware "Changes in the State of Matter, Vaporization and Liquification", please click on the "Changes in the State of Matter ppt, Vaporization and Liquefaction ppt, Liquification ppt" tab.

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Update Time: 2024-11-23

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