"Melting and Solidification" PPT teaching courseware on changes in states of matter

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"Melting and Solidification" PPT teaching courseware on changes in states of matter

Part One Content: Basic Knowledge Key Points

Knowledge point 1: Changes in physical state

1. Solid, liquid and gas are the three common states of matter. The process of matter changing from one state to another is called change of state of matter.

Knowledge point 2 Melting and solidification

2. Among the following physical state changes, the one that belongs to melting is (A)

A. Iron blocks turn into molten iron

B. The water on the plate has dried.

C. The lake surface freezes

D. When water boils, "white gas" appears on the water surface

3. Nanhu Park in Changchun City has pleasant scenery all year round. Which of the following scenery will have solidification during its formation (D)

A. In spring, the snow melts B. In summer, fog surrounds the jungle

C. Autumn, frost hits the branches D. Winter, frozen lake surface

Knowledge point 3: Melting point and freezing point

4. As shown in the figure, the temperature changes with time when two substances melt. Among them, substance B is a crystal and its melting point is 70°C.

5. When a student was exploring changes in the state of matter in the laboratory, he correctly drew four images as shown in the figure based on experimental data. Among them, the one belonging to the amorphous solidification image is (D)

Knowledge point 4: Melting absorbs heat and solidification releases heat

6. Use ice and water of equal mass and temperature of 0 ℃ to cool food. Ice (optional "ice" or "water") is more effective because it takes heat to turn 0 ℃ ice into 0 ℃ water. .

7. Orange farmers learned from the weather forecast that there was going to be a frost. They started spraying water on the orange trees in the evening. As the temperature dropped, the water turned into ice, but the oranges were not frozen. This is because water releases heat during solidification, so that the temperature of the oranges does not drop too low.

Melting and Solidification PPT, Part 2: Comprehensive Ability Improvement

8. The method of making candied haws is to put washed hawthorns on bamboo skewers, then put a certain amount of white sugar into a pot and heat it. After the white sugar melts into syrup, dip the hawthorns in the syrup and wait for the syrup on the hawthorns to release. The heat solidifies (please fill in the names of physical state changes) into a solid state, and the mouth-watering candied haws is ready.

9. You cannot use solder to repair a broken iron pot for cooking because the temperature of the pot will be higher than the melting point of the solder when cooking. You can use solder to repair a broken iron kettle for boiling water because the temperature of the iron kettle will increase when boiling water. Lower than (please fill in "above", "equal to" or "lower") the melting point of solder.

10. When Xiao Ming was watching a news program, he saw a reporter reporting the news: A group of people were seriously injured by an ice skate on the eaves of the building. Xiao Ming analyzed the reasons for the formation of ice skates. It turns out that a layer of snow accumulates on the roof after snow. During the day, under the sunlight, part of the snow melts (please fill in the name of the change of physical state) into water due to heat absorption (please fill in "endotherm" or "endotherm"), and the water changes from When the eaves of the building flow down, they encounter cold and solidify (fill in the name of the change in physical state) into ice. At this time, they need to release heat (select "endotherm" or "exotherm"). Over time, large ice skates formed, posing safety risks.

11. Heating the sea wave, when the temperature reaches 48 ℃, its state (D)

A. It must be a liquid

B. It must be solid

C. Solid and liquid must coexist

D. All three situations are possible

12. In the experiment of "Exploring the laws of melting and solidification of substances", the image drawn is as shown in the figure. The substance (C)

A. It is amorphous crystal

B. It is a solid-liquid mixed state in the CDE section

C. The melting process is stage BC

D. The solidification process lasted 6 minutes

13. (Hezhou High School Entrance Examination) Insert a test tube filled with crushed ice into the middle of a beaker filled with ice particles, and then heat the beaker with an alcohol lamp. When half of the ice in the beaker melts, the ice in the test tube (A)

A. Not melted B. Half melted C. Less than half melted D. More than half melted

14. Picture A is an experimental device for “exploring the laws of material melting”. During the experiment, first put the solid substance and the thermometer into the test tube respectively, then put the test tube into the water in the large beaker, heat it with an alcohol lamp, and observe the melting process of the solid.

(1) Put the solid substance and the thermometer into the test tube respectively, and then put the test tube into the water in the large beaker for heating. The advantage of heating the solid in this way is that the solid is heated evenly;

(2) The image of the solid melting is shown in Figure B. From the image, it can be seen that the substance is a crystal (optional "crystal" or "amorphous"). The melting process of this substance took 8 minutes, and at the 10th minute the substance was in a solid-liquid coexistence state.

Melting and Solidification PPT, Part 3: Expanding Research and Breakthroughs

16. The heavy snow before the Spring Festival in 2019 brought some difficulties to the people's life and production. Xiaolan saw the rescue team spreading a lot of salt on the snow-covered road, so he guessed that adding other substances to the water might affect the freezing point of the water. To this end, he conducted the following exploration process: He put some salt into water, put the brine in a container and put it in the refrigerator to explore the solidification process of the brine. At certain intervals, Xiaolan observes the state of the salt water, measures the temperature, and creates a solidification image from the temperature data recorded during the solidification process, as shown in Figure A.

(1) It can be seen from the image that the salt water starts to solidify at the 10th minute, and the solidification process takes 10 minutes;

(2) It can be concluded from the image that the temperature of the liquid substance of the crystal will not change when it solidifies (select "get bigger", "get smaller" or "unchange");

(3) The freezing point of salt water is -2℃. The results of the experiment verified Xiao Lan’s conjecture, because compared with water, the freezing point of salt water became lower (select “high” or “low”);

(4) If a test tube containing a mixture of ice and water is placed into a melting salt-ice-water mixture, as shown in Figure B, the ice in the ice-water mixture in the test tube will become more (optional "increase") less” or “no change”).

Keywords: Free download of PPT courseware for eighth-grade physics volume 1 of the People's Education Press, download of melting and solidification PPT, download of PPT on changes in state of matter, .PPT format;

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

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Update Time: 2024-09-11

This template belongs to Physics courseware People's Education Edition Physics for Grade 8, Volume 1 industry PPT template

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