"Sublimation and Sublimation" Material Form and Its Changes PPT Courseware 3

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"Sublimation and Sublimation" Material Form and Its Changes PPT Courseware 3

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1. What are the conversion processes between solid and liquid called? Is it endothermic or exothermic?

The change of a substance from solid to liquid is called melting, which is an endothermic process;

The change of a substance from liquid to solid is called solidification, which is an exothermic process.

2. What are the transition processes between liquid and gaseous states called? Is it endothermic or exothermic?

The change of a substance from a liquid state to a gaseous state is called vaporization, which is an endothermic process;

The change of a substance from a gaseous state to a liquid state is called liquefaction, which is an exothermic process.

1. Sublimation and sublimation

Iodine sublimation and desublimation experiments

Put a small amount of iodine in the test tube and close the stopper tightly. Add hot water to the beaker and place the test tube in the beaker to heat. When the test tube is filled with a certain gas, take the test tube out and place it in cold water.

Observe carefully:

1. What state is iodine in before heating?

2. What changes occur during the heating process?

3． What did you see when you stopped heating and cooled down?

The process of a substance changing directly from a solid state to a gaseous state is called sublimation.

During the sublimation process, substances need to absorb heat.

The process of matter changing directly from gaseous state to solid state is called sublimation.

Substances need to release heat during the sublimation process.

2. Sublimation and sublimation phenomena in life

The "ice flowers" on windows in winter are formed by the condensation of water vapor in the air

Think about it: Do you have any questions when you see this light bulb?

1. Why does the light bulb turn black?

2. How is black material formed? …

3. Water cycle in nature

Thinking: How are clouds, rain, snow, fog, dew, and frost formed?

Dew occurs when the water vapor in the air encounters cooler leaves, flowers and plants before early morning when the weather is hot, and liquefies into small water droplets that adhere to their surfaces. This is a liquefaction phenomenon.

The situation of fog and clouds is the same. Both water vapor liquefies into small water droplets when it is cooled in the air. These small water droplets are suspended in the air and are called fog near the ground. They are called clouds at high altitudes. Therefore, fog and clouds They are all phenomena of water vapor liquefaction.

Snow occurs when the weather is cold and the temperature in the air is below zero degrees Celsius. Water vapor condenses into a solid state in the air and becomes hexagonal ice crystals (called snowflakes), which combine with each other to form snow flakes or snow clumps as they fall.

Frost occurs when water vapor on the ground surface condenses directly into a solid state when it encounters temperatures below zero degrees Celsius.

practice

1. Indicate which of the following physical phenomena is a way of changing the state of matter.

(1) The naphthalene balls will become smaller after a period of time. ______

(2) Frozen wet clothes will also dry below 0℃. ______

(3) Asphalt roads melt under the sun. ______

(4) The water sprinkled on the ground dried quickly. ______

(5) When a person wearing glasses goes from a cold outdoor to a warm indoor, a layer of small water droplets will appear on the lenses. ______

(6) On a cold morning, ice flowers condensed on the window glass. ______

2. Regarding the relationship between rain, dew, frost, fog and changes in physical states, which of the following statements is correct: ( )

A. Rainwater is formed by the liquefaction of water

B. Dew is formed by the vaporization of water

C. Frost is formed by the condensation of water vapor

D. Fog is formed by the condensation of water vapor

3． During the change of physical state, heat is released ( )

A. Sublimation, solidification, vaporization B. Melting, sublimation, liquefaction

C. Liquefaction, solidification, sublimation D. Vaporization, sublimation, melting

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"Sublimation and Sublimation" PPT teaching courseware on changes in physical states:

"Sublimation and Sublimation" PPT teaching courseware on changes in the state of matter Part 1 content: Knowledge points Basic knowledge point 1 Sublimation 1. Xiaojie designed a fire-extinguishing bomb with dry ice inside, and dropped the fire-extinguishing bomb into the fire scene. The shell broke and the dry ice sublimated rapidly (filler) State change name) into dioxygen..

"Sublimation and Sublimation" PPT download of changes in physical states:

"Sublimation and Sublimation" PPT Download of Changes in State of Matter Part One: New Knowledge Summary 1. Sublimation and Sublimation 1. Sublimation: The process of matter changing directly from ______ state to ______ state is called sublimation. Sublimation ______ heat. 2. Sublimation: Matter changes directly from ______ state to ____..

"Sublimation and Sublimation" Changes in Physical State PPT:

"Sublimation and Sublimation" PPT on Changes in State of Matter Part One: Preview of Perception 1. Sublimation 1. Concept. The process by which matter is produced by _______________. 2. Features. ________ calories. 3. Application. Sublimation is commonly used in production to obtain ________ to refrigerate food..

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Update Time: 2024-08-01

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