1. A1.2
Properties and
Classification
of Matter

2. Science Science is a way to look at the world. LSL-Science 10
Unit A - 1.2

3. LSL-Science 10
Scientific Models
A model is a representation that serves to explain a scientific phenomenon.
Models are supported by the scientific method which test hypotheses by making predictions about the outcome of an experiment before the experiment is performed. The results provide support or refutation of the hypothesis.
Watch the history of scientific philosophy and the steps of the scientific method
Unit A - 1.2

4. Types of Knowledge Interpretation
Empirical – observable knowledge (operational)
Theoretical – explains or describes scientific observations, not observable. (conceptual)
Interpretation
Indirect form of knowledge that builds on a concept to further describe or explain an observation.

5. Classifying Knowledge
Qualitative Observation
describes qualities of matter or changes in matter.
changes in color, odor, state.
Example:
Mg is an odorless, silver-gray solid that burns with bright white light.

8. Classifying Knowledge
Quantitative observation
Involves a quantity of matter that can be measured.
mass
volume
number of moles
Example
A 5 cm strip of Mg ribbon burned for 3 s leaving 2 mm of ribbon in the tongs.

9. Chemistry
The study of substances, their structure, their properties, and the changes that can occur to substances.

10. Physical Properties
Physical properties – describe the physical appearance and composition of a substance.
E.g., color, hardness, texture, phases, density, ability to conduct heat, electricity.
Physical Change – a change in size, shape or state. It still retains all the same physical properties.
E.g., Melting Ice
Heat

11. Physical Properties Description Boiling Point
Temperature at boiling Point
Melting point
Temperature at melting Point
Malleability
Ability to beat or roll a material
Ductility
Ability to be drawn into a wire.
Color
State
Solid, liquid or gas
Solubility
Ability to dissolve
Crystal formation
Crystalline appearance
Conductivity
Ability to transmit heat or electricity
Magnetism
Magnetic attraction

12. Ca O S2 Ca S O2 Chemical Properties
Chemical Properties - describes the reactivity of a substance
E.g., ability to burn, flash point, reactions with water, air, acids, heat and litmus paper
Chemical Change – a substance changes from one type of matter to another.
Ca O S2
Ca S O2

13. Chemical Property Description Ability to burn
Combustion (flame, heat light)
Flash point
Temperature required to ignite flame
Behavior in air
Degrade, react or tarnish
Reaction in water
Tendency to corrode or dissolve
Reaction in acids
Corrosion, bubble formation
Reaction to heat
Tendency to melt or decompose
Reaction to blue or red litmus
Red-acid, blue-base
Note: in both Physical and Chemical changes there is Conservation of Mass.

14. Matter anything that has mass and occupies space.
STUDYING THE CHANGES TO MATTER IS THE ESSENSE OF CHEMISTRY!
A chemist is most interested in the structure and properties of matter and the changes that occur in matter.
EXAMPLES:
1. Digestion – biochemistry
2. Oil or Gas  plastics – petrochemical engineering
3. Corrosion – chemical engineer
4. Pollution - environmental biologist

15. MATTER MIXTURES PURE SUBSTANCES ELEMENTS COMPOUNDS PROPERTIES ARE
Contains two or more substances
Contains one kind of matter
Heterogeneous
Homogeneous
ELEMENTS
COMPOUNDS
Mixtures where 2 or more components are dissolved and appear as one
Mixture where components are intact and visible
-contains two or more elements in a definite fixed proportion
-cannot be separated by physical means
Only one type of atom that cannot be broken down
Solutions
Colloid
APPEAR AS ONE
SUBSTANCE
Suspension
Mechanical
Mixtures
PROPERTIES ARE
VARIABLE
PROPERTIES ARE
SAME

16. Pure Substances
All particles of the same substance are the same (all particles have the same chemical and physical properties)
2 types of Pure substance
Element – all of these are found on the periodic table. (e.g., sulfur)
Compound – 2 or more chemically combined elements (e.g.,. CO2, MgCl2)
**Note the 2 different types of chemical bonding.

17. Mixtures Combination of pure substances (not chemically combined)
4 types
1. Solutions – homogenous mixture (same parts)
Looks similar throughout
Soft drinks (sugar is dissolved)

18. 2. Mechanical Mixture – (heterogeneous)
You can see all parts clearly
E.g.. soil
*Note the different parts

19. The parts are in different states
3. Suspension – (heterogeneous)
The parts are in different states
E.g., Mud – soil (solid) & water (liquid)

20. 4. Colloid -(heterogeneous)
Similar to suspension but not easy to separate.
Colloids look a lot like solutions.
If you filter both (solution and colloid) a solution will pass through but a colloid will leave behind chunks if one of the phases was a solid.
E.g., Milk, paint, ink…

21. Methods of
Separation

22. Filtration separates a liquid from a solid (mechanical mixture).

23. Distillation separates a solution (homogeneous mixture).

24. Electrolysis breaks a compound apart.
(element)
(element)
Electrolysis breaks a compound apart.

25. Chemical Reactions Characteristics of a chemical reaction include:
The production of a new substance with UNIQUE physical and chemical properties.
A gain or release of energy
And sometimes: A phase change such as the formation of a gas (bubbles) or of a solid (precipitate).

26. Recognizing Chemical Reactions
All reactions produce a new substance with new physical and chemical properties.
All involve the release or absorption of energy.
Heat (thermal energy moving) exits the system – Exothermic
Heat enters the system - Endothermic

27. Some chemical reactions have phase changes:
Bubbles (gas forming)
Precipitates (solid forming)
Cloudiness (solid forming just not falling)

28. Homework:
Questions #1-9 & 11 (pg. 17 textbook)
Read Lab A-3.