Matter

CHAPTER 7

I just finished reading chapter 7 and I discovered that Chem and Physics is kind of connected, especially in the arrangement of particles in the 3 defferent states. We just learnt the exact same thing a few months ago. The first part of this chapter is really a revisit of lower secondary work, about the properties of solid, liquids and gases.This is a solid wall and if you see the way the molecules are arranged in this wall, its kind of interesting.

Okay just look at the liquid inside the glass.

The last one now, gas and their molecules (look at the smoke)

The pictures of the molecules above are called the kinetic model of matter. To break it up a bit,

Solid:

-Molecules are packed together in an orderly and fixed fashion

-high density

-vibrate only about their fixed positions

-hence they have fixed volumes and shapes

Liquid:

-Molecules are packed together (not as much as solid) in a random arrangement

-relatively high densities

-free to move about the liquid

-hence they have fixed volumes but NOT fixed shapes

Gas:

-Molecules are very far apart and randomly arranged

-very low densities

-molecules move about randomly at high speeds

-easily compressed

Brownian motion

It is the random or irregular motion of smoke particles in air that only occurs in fluids (gas or liquids).

You can go to this website it has a short clip on how the particles move.

http://www.aip.org/history/einstein/brownian.htm

How does temperature affect it?

Air molecules have greater speeds at higher temperatures. When the temperature increases, a larger amount of thermal energy is converted to kinetic energy of the air molecules, causing them to move faster.

END OF CHAPTER 7!!!