Chapter 8 Review

Three States of Matter

Summary of types of matter StatePropertiesParticle DescriptionExamples SolidDefinite Shape and volume Closely packed; do not easily change position Ice, sugar LiquidDefinite volume; takes shape of container. Closely packed; able to move past one another Milk, Mercury in thermometer GasOccupies shape and volume of container Spread apart; free to move in all directions Oxygen, steam PlasmaOccupies 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.