13.1 thermal motion of molecules
First, the material composition
1. The material is generally made _____ composition, it is composed of
2. The small molecule, observed by ______________ be observed.
Molecular diameter of approximately 10 -10 m
Exercise 1: the molecule as a sphere, a close next tile to a layer (like each grid Go put a pawn), consisting of a single molecule of a square side length of l cm. How many molecules of the square that about? What is the approximate number of molecules in these times the number of the world's population?
The answer: about 1X10 8 Ge approximately 0.08 times
Second, the diffusion phenomenon
(A) diffusion of the gas
Watch the gas diffusion video: https://www.bilibili.com/video/av57929251/
Experiments Notes: reddish-brown nitrogen dioxide gas in the lower
3. diffusion : ___
4. diffusion phenomena explain :( 1) _______
（2）________
(B) liquid diffusion
Watch the liquid diffused video: https://www.bilibili.com/video/av57898313/
(C) solid diffusion
Watch solid diffusion video: https://www.bilibili.com/video/av57898532/
3. diffusion phenomena, for example: (beneficial) ___________
(harmful)___________
Example 1: The following is not part of the diffusion phenomenon ()
A. Next to the flowers smell the flowers B. Sprinkler water spilled on the ground
C. A few days salted with salt fish, salty fish have a D. Put sugar into the water, while all the water made sweet
Third, the thermal motion of molecules
According to the above study: students know molecule is in unceasing random motion, since motion, motion speed with what's on it?
Watch diffusion and temperature dependence Video: https://www.bilibili.com/video/av57929600/
The experiment shows: the temperature _____, the diffusion ______ _____ the molecular motion (thermal motion of molecules )
For example:
Fourth, the intermolecular forces
( A ). Attraction between molecules
Example one:
Watch compression column Lead Video: https://www.bilibili.com/video/av57928664/
Example 2: Tensile difficult ballpoint
(B). Repulsion between molecules
Example:
6. There are interactions between the molecules and . And _______ present ;
_______ ______ and increase with increasing distance from _______ molecules, molecules with reduced distance and _______ (similar magnet)
7. If showing the distance r between the molecules, r 0 equilibrium position indicated molecule :
(Gravity = repulsive force when the distance between molecules is called the equilibrium position R & lt 0 )
When the distance between the two molecules of R & lt <R & lt 0 , the attraction ______ repulsion force performance as ;
When the distance between the two molecules of R & lt R & lt = 0 , the attraction ______ repulsion
When the distance between the two molecules of R & lt> R & lt 0 , the attraction ______ repulsion force performance as ;
When the distance between the two molecules r> 10 -fold molecular diameter , ___; (such as gas)
Example 2: As shown, a very thin line to a clean glass plate measuring spring hanging under the force gauge, note the dynamometer readings; horizontal contact surface and then the glass plate, the glass plate is slightly pulled up, the glass before leaving the surface plate, the spring dynamometer readings ______ (fill "large", "small" or "unchanged"), this phenomenon is described ______.
Five microscopic model, the three states of matter
|
Physical state |
Microscopic properties |
Macroscopic properties |
|||
| Intermolecular distance |
Intermolecular forces |
The presence of fixed shape |
Have a fixed volume |
Whether the liquidity |
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| Solid State |
|
Great |
|
|
|
| Liquid |
Larger |
Larger |
|
|
|
| Gaseous state |
Great |
|
|
|
|
Fives. Exercise
1. The following phenomena belonging diffusion is (B)
A. Spring catkins flying. B . Xia Tianhuai flower fragrance. C. Autumn autumn rain. D. Winter snowflakes
Ideas: Molecular invisible to the human eye, the human eye to see things but certainly not molecular motion of the object does not belong proliferation, proliferation must be molecular motion
2. Zhang students are not careful around the house in a cup was broken in half, he thought physics class the teacher talked about the composition of the existence of gravitational pull between the molecules of matter, so he rushed to the cup gracefully in accordance with the original look , and fasten them with a rope. The reason few days later, when he untied the rope, it is a two and a half cups (not broken mirror ends it), this phenomenon is (D)
A. No attraction between the molecules of this cup
B. When the cup is broken, the attraction between molecules consumed done
C. Local contact with each other far apart, repulsion played a major role.
D. Where contact with each other by a distance larger than the diameter very weak, molecular interaction forces
Long emperor arrogance