1. All the materials you can hold or touch are matter.
Chapter 2 Matter
All the materials you can hold or touch are matter.

2. What Is Matter? You are made of matter
Your textbook is made of matter.
The air you breathe is matter.
Anything that has mass and occupies space is matter.
Light, Sound, and Electricity are NOT matter because they have no mass or volume!

3. Matter All matter is made up of atoms.
Element – a substance that cannot be broken down into simpler substances.
Atom – the smallest particle that has the properties of an element
Compound – a substance made of atoms of more than one element bound together.

4. Earth

5. Human Body

6. Matter
Molecule – the smallest unit of a substance that exhibits all of the properties characteristic of that substance
H2O
CO2
Chemical formula – the chemical symbols and numbers indicating the atoms contained in the basic unit of a substance
C16H10N2O2

7. Matter
Pure substance – any matter that has a fixed composition and definite properties.
CO2 - C3H8O
H2O
Mixture – a combination of more than one pure substance.
Milk
Grape juice
Windex

8. Mixtures
Homogeneous – mixing occurs between the individual units and is the same throughout
Salt dissolved in water
Heterogeneous – not uniformly mixed
Flour suspended in water

9. Mixtures
Miscible – describes two or more liquids that are able to dissolve into each other in various proportions
Rubbing (denatured) alcohol
Immiscible – describes two or more liquids that do not mix into each other.
Oil and vinegar salad dressing

10. Matter and Energy

11. Kinetic Theory
All matter is made of atoms and molecules that act like tiny particles.
These tiny particles are always in motion. The higher the temperature, the faster the particles move.
At the same temperature, more massive (heavier) particles move slower than less massive (lighter) particles.

12. Kinetic Theory
The kinetic theory is a useful tool for visualizing the differences between the three common states of matter: solids, liquids, and gases
Solids – have a rigid structure
Liquids – have a less rigid structure than solids and can move about, or flow.
Liquids have a definite volume that can be measured.

13. Kinetic Theory
The kinetic theory is a useful tool for visualizing the differences between the three common states of matter: solids, liquids, and gases
Gases – gases are in a constant state of motion and rarely stick together
Gases will fill any container
Due to their rapid movement, a gas exerts pressure on its container

14. Change of state for water
Gaseous steam
Relative energy
540 Calories per gm / C
Liquid water
80 Calories per gm / C
Solid ice
100 C
0 C

15. Change of state for water
Gaseous steam
Relative energy
540 Calories per gm / C
Melting (energy absorbed)
Freezing (energy released)
Evaporation (energy absorbed)
Condensation (energy released
Liquid water
80 Calories per gm / C
Solid ice
100 C
0 C

16. Energy’s Role Energy must be added to cause melting or evaporation
Energy is transferred in all changes of matter
Changing state does not change composition or mass
Evaporation – the change of a substance from a liquid to a gas

17. Energy’s Role
Sublimation – the change of a substance from a solid to a gas
Dry ice (solid CO2)
Ice and snow at very high altitudes will sublime
Ice in your freezer at home will sublime
Whether it is ice, water, or steam, water in any form is always made of H2O molecules.

18. Energy’s Role
Law of Conservation of Mass – Matter can neither be created nor destroyed.
Law of Conservation of Energy –
Energy can neither be created nor destroyed.
[See figure 2-17 on page 51 of text.]
Mass A (wood + air) = Mass B (carbon +
carbon dioxide + water)

19. Properties of Matter

20. Chemical and Physical Properties
Chemical property – the way a substance reacts with others to form new substances with different properties.
Involve the reactivity of elements or compounds
Flammable
Able to rust or oxidize
Reactivity – the ability of a substance to combine chemically with another substance.

21. Chemical and Physical Properties
Physical property – a characteristic of a substance that can be observed or measured without changing the composition of the substance.
Physical Properties
Shape, color, odor, texture
Melting point, boiling point, density, strength, hardness, conductivity, etc.

22. Chemical and Physical Properties
Melting point – the temperature at which a solid becomes a liquid
Boiling point - the temperature at which a liquid becomes a gas (below the surface)

23. Chemical and Physical Properties
Density – is calculated by dividing the object’s mass by its volume. D = m/V
Buoyancy – the force with which a more dense fluid pushes a less dense substance upward

24. Density of some items Item Chem Formula Density g/cm3 Air Mixture
Gasoline
0.7
Water
H2O
1.00
Lead Pb
11.3
Iron Fe
7.86
Helium He
Ice
0.92

25. Chemical and Physical Properties
Properties help determine uses –
Copper is used in electrical power lines, telephone lines, and electrical motors because of its good electrical conductivity.
Ethylene glycol remains a liquid at temperatures that would normally boil or freeze in a car radiator. (Antifreeze)

26. Chemical and Physical Changes
Materials that stay in the same state under normal conditions
Surgical steel
Concrete
Glass
Materials that change and combine
Gasoline
Car batteries
Human metabolism (oxidation)
Digestion, etc.

27. Chemical and Physical Properties
Chemical changes are changes in composition

28. Chemical and Physical Properties
Electrolysis – the process by which water can be broken down into hydrogen and oxygen.
The atoms of oxygen and hydrogen are not destroyed, but rearrange themselves to form hydrogen and oxygen gas. [See figure 2-22 in text.]
Burning of gasoline into C, CO2, & H2O
A change in odor or color is a good clue that a substance is changing chemically
i.e. food burning, paint fading, etc.

29. Chemical and Physical Properties
Physical changes do not change composition
Physical change – a change in the physical form or properties of a substance without a change in composition.
Grinding Quartz crystals into sand
Grinding peanuts into peanut butter
Making gold jewelry