1. States of Matter Fluids and Density
Chapter 7 Overview
States of Matter
Fluids and Density

2. What is Matter?
Matter – anything that has mass and volume, measured in grams or kilograms
Volume – amount of space
taken up by a substance,
measured in ml, L, cm3

3. Kinetic Molecular Theory
Kinetic – movement
Molecular – molecules - made of atoms
Theory – idea of how things work
Particles in solids, liquids
and gasses are always in
motion – but all move
differently

4. States of Matter Solid – definite shape and volume
Particles only vibrate
Liquid – definite volume but shape is of container it is in
Particles slide past each other
Gas – both volume and shape are determined by surroundings
Particles are far apart, move
quickly but do collide

6. Kinetic Molecular Theory
1. All matter made of very small particles –atoms
2. There are spaces between the particles
3. Particles are always moving
4. Energy makes particles move – more energy the faster they move

7. What Happens When We Add Heat?
Particles move faster
More collisions
More energy
= Thermal Expansion
Example – telephone wires

8. What Happens When We Cool Things?
Particles move slower
Less collisions
Less energy
= Thermal Contraction
Example – thermometer

9. Difference Between Heat and Temperature
When two substances with different thermal energy contact each other energy flows from high to low
Heat – the energy transferred form
one material to another
Temperature – reading of a substance’s average kinetic energy

10. Changes of State Melting – solid to liquid Evaporation – liquid to gas
Condensation – gas to liquid
Solidification – liquid to solid
Sublimation – solid directly to gas (dry ice)
Deposition – gas directly to solid (frost)

11. Unique Features of a Substance
Melting Point – temp. when a solid goes to a liquid
Boiling Point – temp. when a liquid goes to a gas

12. Fluids and Density Fluid – matter that can flow – liquids and gasses
Density – the mass of a given volume
The more densely packed together the particles the more dense the substance is
Can be altered by temp.
Solids more dense then liquids – except water

13. Measuring Density
To find density we need to know the mass and volume of a substance
Mass – use a scale
Volume - # of cm cubes to fill the object or use displacement
Fluids measured in g/ml - Solids in g/cm3
Density = Mass
Volume