1. Properties of Matter
Chapter 2

2. 2-1: Classifying Matter

3. Pure Substances
Pure substance – matter that always has exactly the same composition
Table salt and table sugar are two examples of pure substances.
Substances can be classified into two categories—elements and compounds.

4. Elements
Element – a substance that cannot be broken down into simpler substances
An element has a fixed composition because it contains only one type of atom
Examples: The elements oxygen and nitrogen are the main gases in the air you breathe.

5. Elements
Chemists use symbols of one or two letters to represent elements. The first letter is always capitalized. If there is a second letter, it is not capitalized.
C represents carbon.
Al represents aluminum.
Au represents gold.

6. Compounds
Compound – a substance that is made from two or more simpler substances and can be broken down into those simpler substances
Ex. – Water is composed of the elements hydrogen and oxygen. Oxygen and hydrogen are gases at room temperature, but water is a liquid.

7. Mixtures
Heterogeneous mixture – the parts of the mixture are noticeably different from one another
The sand is a heterogeneous mixture of different kinds of grains.

8. Mixtures
Homogeneous mixture – the substances are so evenly distributed that it is difficult to distinguish one substance in the mixture from another
The spoon is stainless steel, a homogeneous mixture of iron, chromium, and nickel.

9. Solutions
Solution – The mixture that forms when substances dissolve and form a homogeneous mixture

10. 2-2: General Properties of Matter

11. Matter – anything that has mass and volume
Properties – characteristics of matter
Ex. – Color, odor, shape, texture, and hardness

12. Mass – The amount of matter in an object
The mass of an object does not change unless some matter is either added to or removed from an object

13. Weight – response of mass to the pull of gravity
Gravity – force of attraction between all objects in the universe

14. Volume – the amount of space an object takes up
Measured in liters (L), milliliters (mL), and cubic centimeters (cm3)
1 L = 1000 mL or 1000 cm3
______ mL = 3.5 L
3500 mL = 3.5 L

15. Densities of Some Common Substances
Density – the mass per unit volume of an object
Densities of Some Common Substances
Substances
Density (g/cm3)
Air
0.0013
Gasoline
0.7
Wood (oak)
0.85
Water (ice)
0.92
Water (liquid)
1.0
Aluminum
2.7
Steel
7.8
Silver
10.5
Lead
11.3
Mercury
13.5
Gold
19.3

16. 2-3: Phases of Matter

17. Phase – state in which matter can exist: solid, liquid, gas or plasma

18. Sodium Chloride (Table Salt)
Solid – matter with a definite shape and a definite volume
Crystal – solid in which the particles are arranged in a regular, repeating pattern
Quartz
Sodium Chloride (Table Salt)

19. Amorphous solid – solid that loses its shape under certain conditions
Sealing Wax

20. Liquid – matter with no definite shape but with a definite volume
Viscosity – the resistance of a liquid to flow
Honey has a higher viscosity than water

21. Gas – matter with no definite shape or volume
Plasma – high-energy phase of matter
Plasma is one of the most common phases of matter in the universe

22. 2-4: Phase Changes

23. Solid-Liquid Phase Changes
Melting – the change of a solid to a liquid
Melting point – the temperature at which a solid changes to a liquid

24. Solid-Liquid Phase Changes
Freezing – the change of a liquid to a solid
Freezing point – the temperature at which a liquid changes to a solid
The freezing point of a substance is equal to its melting point

25. Liquid-Gas Phase Changes
Vaporization – the change of a substance from a liquid to a gas
Evaporation – vaporization at the surface of a liquid

26. Liquid-Gas Phase Changes
Boiling – the process in which particles inside a liquid as well as those on the surface change to a gas

27. Liquid-Gas Phase Changes
Boiling point – temperature at which a substance changes from the liquid phase to the gas phase
Boiling point of water – 100 degrees Celsius
Boling point of a diamond – 4200 degrees Celsius

28. Liquid-Gas Phase Changes
At high altitudes, air pressure is lower, so the boiling point is reduced.
Water will boil at a temperature lower than 100 degrees Celsius at high altitudes

29. Liquid-Gas Phase Changes
Condensation – the change of a gas to a liquid
Water vapor in the surrounding air loses heat energy when it comes in contact with the cold glass
Water vapor condenses and becomes liquid

30. Solid-Gas Phase Changes
Sublimation – the surface particles of a solid escape directly into the gas phase
Ex. – snow turns to water vapor
Ex. – dry ice

31. Heat, Temperature, and Phase Changes
Heat is energy that causes the particles of matter to move faster and farther apart. As the particles move faster, they leave one phase and pass into another.

32. 2-5: Chemical Changes

33. Observing Chemical Properties
Chemical property – any ability to produce a change in the composition of matter

34. Observing Chemical Properties
Two chemical properties:
Flammability – a material’s ability to burn in the presence of oxygen
Reactivity – The property that describes how readily a substance combines chemically with other substances
Iron + Oxygen = Rust

35. Chemical Changes
Chemical changes – the changes that substances undergo when they change into new and different substances

36. Chemical Changes
A change in color is a clue that a chemical change has produced at least one new substance (most of the time)
As a match burns, it shrivels up and turns black.

37. Physical Property
Physical property can be observed with senses and can be determined without destroying matter

38. Physical Changes
Physical change – a change in size, shape, or state of a substance but no new substance is formed