1. Matter & Change

2. Matter classification

3. Try to Answer the Following Questions
1. A compound is formed by…
A single element
Two or more atoms
Two or more nuclei
Electrons and neutrons
Which statement best describes atoms and molecules in a liquid?
They vibrate rapidly
They form a definite structure
They slide past each other
They cannot be rearranged
What is the process of a liquid changing to a gas called?
Ice melting into water is a physical or chemical change?
Which state of matter has neither a definite shape nor definite volume?

4. How did you do? “B”: two or more atoms
“C”: atoms and molecules in a liquid slide past each other
Evaporation
Physical
Gas

5. Hypothesis vs. Theory vs. Scientific Law
A HYPOTHESIS is a proposed reason for what is observed and it needs to be tested by means of an experiment
A THEORY is a thoroughly tested explanation of why experiments give certain results.
A theory tends to explain WHY things happen. You cannot prove a theory.
Scientific Law is a concise statement that summarizes the results of a broad spectrum of observations and experiments.
Scientific Law tends to explain WHAT things happen. You can prove a scientific law.

6. Why does it “matter”? What is matter?
“Everything that takes up space and has mass”
“Stuff”
What is mass?
Amount of matter an object contains
“How much stuff an object has”
**This is NOT the same as weight

7. Substances vs Mixtures
Matter is broken into categories. Matter can be either a substance or a mixture.
A substance has a uniform (constant) composition. This means that no matter the sample it will always have the same physical properties (looks the same).

8. Two Types of Substances
Compounds
Made up of two or more types of atoms.
A given compound always contains the same, fixed ratio of elements.
Elements can combine in different ratios to form different compounds.
Ex: Table Salt, NaCl
Glucose, C6H12O6
Elements
Made up of only one type of atom.
Look at the periodic table!
Ex: Ca, K, Cl

9. Pure Substances Element composed of identical atoms
EX: copper wire, aluminum foil

10. Pure Substances Compound
composed of 2 or more elements in a fixed ratio
properties differ from those of individual elements
EX: table salt (NaCl)

11. Two different compounds, each has a definite composition.
Pure Substances
For example…
Two different compounds, each has a definite composition.

12. Mixtures A mixture is a physical blend of two or more substances.
Mixtures are ALWAYS physical changes

13. Types of mixtures Heterogeneous mixtures -not uniform in composition
-more than one phase (a phase is a part of a system that is uniform in composition and physical state)
-Can be physically separated
-Can visibly see differences
-examples: tossed salad, gravel mix, rock, river water

14. Types of Mixtures Homogeneous mixtures -uniform in composition
-one phase
-also called a solution
-easily confused with substances
-examples: salt water, kool-aid

15. Solutions Another name for a homogenous mixture
Can be either a liquid or gas
Phase is used to describe any part of a sample with uniform composition and properties
Single phase
3 phases

16. A good question to ask yourself when trying to decide if something is a substance or a homogeneous mixture is to ask yourself if there is more than one kind of this material.
What is gasoline?
What is milk?
Are there different concentrations of salt?
if so then it is a mixture!

18. Examples: element graphite hetero. mixture pepper compound
solution
graphite
pepper
sugar (sucrose)
paint
soda

19. Separating a Mixture
There are several ways to separate a mixture. A good way to figure out if matter is a substance or a solution is to see if you can separate it into parts by doing one of the following:
Physical separation
Filter (particle size, uses gravity)
Magnet (magnetism)
Decanting-pouring off a liquid (density)
Distillation (boiling point)
Centrifuging (density)
Chromatography (separates based on solubility)
Crystallization

21. Properties of Matter
Matter contains both physical and chemical properties.
A physical property is a quality of a substance that is observed without changing the substance’s original composition.
Examples: Color, mass, density, hardness, odor, boiling point, solubility

22. Chemical Properties
Chemical properties are a little more difficult to determine. A chemical property is the ability of a substance to undergo chemical reactions.
Examples: Rot, rust, decompose, decay, grow ferment

23. Chemical vs. Physical Changes
Chemical Change
A change in the composition of a substance OR
Changing a substance to form a new substance
Examples: fermenting, rotting, burning, color change, gas given off, heat
Physical Change
A change in a substance without a change in its composition
Examples: mixing, cutting, changing from a solid to a liquid, dissolving, boiling

24. Clues that a Chemical Reaction has taken place
Five possible clues that a chemical change has taken place. 1) A transfer of energy. Energy given off as heat or light 2) A color change 3) The formation of a precipitate Precipitate: A solid that forms and settles out of a liquid mixture. 4) Formation of a gas 5) Cannot be changed back to original reactants. Observing a clue does NOT necessarily mean a chemical change has taken place The only way to be sure is to test the composition of the substance before and after.

25. Figure it out- Chemical or Physical?
Metals are shiny
Milk gets sour when left out
Metals can be made into wires
Bread rises when cooked
Nonmetals are not able to conduct electricity
P, C, P, C, P

26. States of Matter There are four states of matter: solid, liquid, gas
Plasma –gas like
What is compressibility?
Ability to squash something into a smaller volume

27. Solid, Liquid, Gas
(a) Particles in solid (b) Particles in liquid (c) Particles in gas

28. Solids Has a definite shape and volume
The particles are packed close together
Are almost incompressible, difficult to squeeze to a smaller volume
Very low kinetic energy

29. Liquids Indefinite shape—takes on the shape of the container its in
Definite volume
Flows, particles are arranged randomly and are close, but not as close as solids
Almost incompressible
Low to moderate kinetic energy

30. Gas Indefinite shape Indefinite volume
The particles are usually much farther apart
Gases are easily compressed into a smaller volume
High kinetic energy

31. Fourth State of Matter Plasma
very high KE - particles collide with enough energy to break into charged particles (+/-)
gas-like, variable shape & volume
stars

32. Kinetic Molecular Theory
KMT
Particles of matter are always in motion.