Chapter 8 Review

Three States of Matter

Summary of types of matterState Properties Particle Description Examples

Solid Definite Shape and volume

Closely packed; do not easily change position

Ice, sugar

Liquid Definite volume; takes shape of container.

Closely packed; able to move past one another

Milk, Mercury in thermometer

Gas Occupies shape and volume of container

Spread apart; free to move in all directions

Oxygen, steam

Plasma Occupies shape and volume of container

Gas like mix of negatively and positively charged particles

Mercury vapor in fluorescent tube, sun and stars

Phase Triangle – Changes between states of matter

Simple Phase Change Diagram

Pressure The total amount of force exerted by a gas

depends on the size of its container. Pressure is the amount of force exerted per unit of area. P = F / A

The pascal (Pa) is the SI unit of pressure. Most pressures are measured in kPa (kilopascals)

Earth’s atmosphere exerts a pressure on everything within it. At sea level, atmospheric pressure is 101.3kPa.

Boyle’s Law

The pressure of a gas depends on how often its particles strike the walls of the container. If you squeeze some gas into a smaller space, its particles will strike the walls more often, giving it increased pressure.

According to Boyle’s law, if you decrease the volume of a container of gas, the pressure of the gas will increase, provided the temp. does not change.

Increasing the volume would cause the pressure to drop.

Charles’s Law According to Charles’s Law, the

volume of a gas increases with increasing temperature, provided that the pressure doesn’t change.

A gas shrinks with decreasing temperature.

As a gas is heated, its particles move faster and faster, and its temp. increases. Because the gas particles move faster, they begin to strike the walls of their container more often and with more force. If the walls are free to move, the gas pushes the walls out and expands.

Pascal’s Principle The ideal press consists of two

pistons of areas ( a , A ) enclosed between them incompressible liquid as in figure When a small force ( f ) acts on the small piston ( a ) , it exerts a pressure ( p = f/a ).  

The increase in pressure P is equally transmitted to every part of the liquid & to the walls of the container according to Pascal's Principle till it acts on the large piston ( A ) to produce very large force ( F = P x A ) causes the load to rise .

To keep the large piston (A) at equilibrium with the small one (a) a load = F is placed on the large piston .

P = f/a = F/A

Archimedes’ Principle

According to Archimedes’ Principle, the buoyant force on an object in a fluid is equal to the weight of the fluid displaced by the object.

Bernoulli’s Principle As the velocity of the fluid

increases, the pressure exerted by the fluid decreases

Fluids flow faster when they are forced to flow through narrow spaces. The reduction in pressure

in these spaces is an example of Bernoulli’s principle called the Venturi effect.