1. UNIT 1 Introduction to Chemistry

2. CLASSIFICATION OF MATTER

3. Matter
Chemistry involves the study of the structure, composition, properties, and the behavior of matter.
Matter is the physical material of the world
It has mass, volume, and inertia
> 100 elements constitute all matter
Scientists use Kinetic Molecular Theory (KMT) as a way to model the structure of matter
All matter can be classified according to its phase and its composition

4. Kinetic Molecular Theory
KMT states the following:
All matter is composed of tiny particles.
These particles are in constant motion.
The amount of motion is proportional to temperature. Increased temperature means increased motion.
Solids, liquids and gases differ in the freedom of motion of their particles and the extent to which the particles interact.

5. Phases of Matter
All matter can be classified into 4 phases (physical states)
Solid – definite volume and shape; particles packed in fixed positions
Liquid – definite volume but indefinite shape; particles close together but not in fixed positions
Gas – neither definite volume nor definite shape; particles are at great distances from one another
Plasma – high temperature, ionized phase of matter as found on the sun.
The amount of internal thermal energy (heat) determines the state of matter.

6. Composition of Matter
Matter
Pure Substance
Element
Compound
Mixture
Homogeneous Mixture
Heterogeneous
All matter can be divided up into four main categories.

7. PHYSICAL / CHEMICAL PROPERTIES & CHANGES

8. Properties of Matter
Property – any characteristic that allows us to recognize a particular type of matter and to distinguish it from other types of matter
Each substance has a unique set of physical and chemical properties.
Physical Properties are measured without changing the substance.
e.g., color, density, odor, melting point
Chemical Properties describe how substances react or
change to form different substances
e.g., rusting of an iron nail at room temperature, sodium reacts violently with water, radioactive decay, lack of reactivity

9. Properties of Matter-Practice
DIRECTIONS: Classify each of the following properties
as either physical or chemical.
Blue color
Density
Flammability
Solubility
Reacts with acid to form hydrogen gas
Supports combustion
Sour taste
Melting point
Reacts with water to form a gas
Hardness

10. Using Properties of Matter
Separation techniques exploit the differences in
properties of matter
Filtration - remove solid from liquid
Distillation - boil off one or more components of a mixture
Chromatography - exploit the solubility of components

11. accompanied by a transfer of energy***
Changes of Matter
***Both physical and chemical changes are ALWAYS
accompanied by a transfer of energy***
PHYSICAL CHANGE - changes in the physical properties of matter
Properties of a material change but the composition
remains the same

12. Changes of Matter 3 basic categories
Phase change (e.g. melting, freezing, condensing, sublimation, etc.)
Mechanical change (e.g., ripping, chopping, breaking, cutting, etc.)
Dissolving a solute into a solvent (e.g., forming a solution from CuSO4)
Can be classified as reversible and irreversible
Which of the above would be reversible/irreversible?

13. Changes of Matter
CHEMICAL CHANGE-one or more substances transforms into one or more chemically different substances
Composition of matter ALWAYS changes (i.e., change in identity)
Created by chemical reactions

14. Changes of Matter Indicators of a chemical reaction: Color change
Formation of a gas
Formation of a solid
Formation of an odor
Heat/light released/absorbed
Change in pH

15. Changes of Matter DIRECTIONS: Classify each of the following examples
as a physical or chemical change.
Sodium hydroxide dissolves in water.
Hydrochloric acid reacts with sodium hydroxide to produce a salt, water, and heat.
A pellet of sodium is sliced in two.
Water is heated and turned to steam.
Potassium chlorate decomposes to potassium chloride and oxygen gas.
Iron rusts.
Ice melts.
Acid on limestone produces carbon dioxide gas.
Milk sours.
Wood rots.

16. PHASE CHANGES & PHASE DIAGRAMS

17. Phase Changes
Phase Change - transition when a solid, liquid or gas changes from one phase to another due to the increased/decreased motion of molecules
Phase changes often occur due to the absorption or release of heat energy
Phase changes come from the competition between temperature and attractive intermolecular forces
Intermolecular forces tend to attract molecules together into rigid structures
As the amount of thermal energy increases in a substance, this rigid structure is disrupted

18. Phase Changes SOLID - LIQUID
melting - (solid to liquid) - increased molecular motion due to absorbed heat
freezing - (liquid to solid) decreased molecular motion due to released heat
Both occur at the same temperature called the melting point or the freezing point

19. Phase Changes LIQUID - GAS
vaporization (boiling/evaporating) - (liquid to gas) - increased molecular motion due to absorbed heat
condensation – (gas to liquid) decreased molecular motion due to released heat
Both occur at the same temperature called the boiling point or the condensation point

20. Phase Changes SOLID - GAS
sublimation - (solid to gas) - increased molecular motion due to absorbed heat
deposition - (gas to solid) decreased molecular motion due to released heat

21. Phase Diagrams
Phase Diagram (Heating and Cooling Curve) – a common way to represent the various phases of a substance and the conditions under which each phase exists.

22. Warming
(Endothermic)
Energy is absorbed
GAS
LIQUID / GAS
LIQUID
SOLID / LIQUID
Cooling
(Exothermic)
Energy is released
SOLID

23. (Boiling/Evaporating)
Vaporization
(Boiling/Evaporating)
Boiling Point and Condensing Point are at the SAME temp!!!
Condensing Point
Boiling Point
Condensing
Melting
Melting Point and Freezing Point are at the SAME temp!!!
Melting Point
Freezing Point
Freezing