1. Classification of Matter
Stuff of which all materials are made: anything that has mass and takes up space.

2. Matter All matter is composed of atoms
Atoms are extremely small building blocks of matter
Atoms cannot be broken down into smaller pieces by chemical means
Atoms are the smallest distinct units in a sample of matter

3. Physical Classification

4. Let’s look at Pure Substances

5. Pure Substances - Elements
Pure substance composed of one type of atom
cannot be decomposed into other substances.
Represented by one or two letter symbol
EX: copper wire (Cu), aluminum foil (Al)

6. Pure Substances - Molecules
Molecule – a combination of 2 or more same atom that are covalently bonded.
A molecule is the smallest particle of a substance which exhibits the physical and chemical characteristics of the substance.
Diatomic molecules of elements :
H2 O2 N2 Cl2 F2 I2 Br2

7. How are ELEMENTs represented?
Molecule

8. Pure Substances - Compounds
composed of two or more elements chemically combined in a fixed ratio
properties differ from those of individual elements
Represented by a chemical formula
EX: water (H2O) table salt (NaCl)

9. Pure Substances - Compounds
For example…
Two different compounds, each has a definite composition.

10. Pure Substances - Compounds
Compounds a compound of 2 or more different elements bonded together in a fixed proportion.
H2O CO2 CaSO4 HBR
Na2O KOH H2 CO3

11. How are COMPOUNDs represented?

12. Laws for Compounds Law of Definite Composition
A given compound always contains the same, fixed ratio of elements.
Law of Multiple Proportions
Elements can combine in different ratios to form different compounds.

13. Pure Substances - Compounds
Slight differences in combinations of atoms can have large difference in properties H2O - water H2O2 – hydrogen peroxide C2 H6O – ethanol, drinkable C2 H6O2 – ethylene glycol, poisonous

14. Pure Substances Same kind of particles throughout Compounds
Can be decomposed into simpler substances by chemical changes, always in a definite ration
Elements Cannot be decomposed into simpler substances by chemical changes

15. Let’s Look at Mixtures

16. Mixtures
Mixtures are two or more substances that are physically combined.
Mixtures do not have a fixed composition
Mixtures do not have constant boiling points or melting points
Variable composition
Components retain their characteristic properties

17. Mixture May be separated into pure substances by physical methods
Mixtures of different compositions may have widely different properties.

19. Mixtures Mixtures can be described by how uniform they are throughout.
Heterogeneous
Homogeneous

21. Mixtures - Heterogeneous
Heterogeneous mixture
Two or more phases (with same or different physical states)
Each phase has different properties
Not uniform throughout
Examples: oil and water, sand and water, milk, fresh squeezed lemonade

22. Mixtures – Homogenous solution
Homogenous mixture
One phase – must always be the same
Uniform throughout
Same composition in a sample
Examples: sugar, salt water, rubbing alcohol

23. Mixtures - Homogenous Alloys – combination of two or more metals
Examples: brass and steel

24. How do we represent a MIXTURE?
Two or more substances that are mixed together but are NOT chemically bonded.

25. Element, Compound or Mixture?
Check for understanding
Element, Compound or Mixture?

26. Element, Compound or Mixture?

27. Element, Compound or Mixture?

28. Element, Compound or Mixture?

29. Check for Understanding
Number your papers from 1 to 15. Classify the following as an element, compound, or mixture (heterogeneous or homogeneous).
Penny 6. Oxygen 11. Sea water
Air 7. Sugar 12. Water
Al foil 8. Chlorine gas 13. Graphite
Windex 9. Salad dressing 14. Pepper
Steel 10. Table salt 15. Paint

30. How did you do? 6. Oxygen – Element
Penny – Mixture Homogenous (zinc and copper solids)
Air - Mixture Homogenous (gases)
Aluminum foil - Element
Windex – Mixture Homogenous
Steel – Mixture Homogenous (iron and carbon solids)
6. Oxygen – Element
7. Sugar – Compound (C6H12O6)
8. Chlorine Gas – Element

31. How did you do? 9. Salad Dressing - Mixture Heterogenous
10. Table salt – Compound (NaCl)
11. Sea water – Mixture Homogenous
12. Water – Compound
13. Graphite – Element (Carbon)
14. Pepper – Mixture - heterogeneous
15. Paint – Mixture - heterogeneous

32. Classifying Matter

33. Can it be physically separated?
Matter Flowchart
MATTER
yes no
Can it be physically separated?
MIXTURE
PURE SUBSTANCE
Is the composition uniform? no
yes
Can it be chemically decomposed? no
yes
Homogeneous Mixture
(solution)
Heterogeneous Mixture
Compound
Element
Colloids
Suspensions