Chap 4

Extra help and Study Guide

 

Review of Main Ideas

 

Section 1

All matter is composed of tiny particles (molecules) that are in constant motion

In the solid state an attractive force (a pull (from inside the molecule) that makes them want to stay with each other) between these particles holds them in place to vibrate

o  They have a defined volume & shape

Particles in the liquid state have defined volumes but are free to move about in the liquid

o  they have no defined shape

 

Section 2

Thermal energy is the total energy of the particles in a sample of matter

Temperature is the average kinetic energy of the particles in a sample

An object gains thermal energy when it changes from:

o  a solid to a liquid = melting

o  a liquid to a gas = vaporization

An object loses thermal energy when it changes from:

o  a gas to a liquid = condensation

o  a liquid to a solid = freezing (only called that with water really) but the action is the same

 

Section 3

Pressure is force divided by area

Fluids exert a buoyant force the upward direction on object immersed in them

An object will float in a fluid that is more dense than itself