1. Ch. 2 Matter & Change

2. Properties of Matter Matter: anything that has mass and takes up space
Mass: amount of matter the object contains
Physical Property: characteristic that can be observed or measured without changing the sample’s composition
Extensive properties: depends on the quantity of matter (length, mass, volume)
Intensive properties: independent of the quantity present (melting & boiling point, density)

4. Properties of Matter
Chemical Property: ability of a substance to combine with or change into one or more substances
*can only be determined by changing the substance
Ex. Iron combines with oxygen to form iron oxide (rust)
Each substance has a unique set of chemical and physical properties

5. Changes in Matter
Physical Change: alter a substance without changing its composition
Changes state – all transition like melting, freezing, boiling, condensing
Can be classified as reversible or irreversible
Chemical Change: a process that involves one or more substances changing into a new substance
Known as a chemical reaction
New chemical: different composition and properties

6. Evidence of a Chemical Change
Color change
Energy changes – gets cold or hot
Odor change
Precipitate (solid formed from a mixture of solution)
Gas produced – bubbles
Irreversible process
New properties

7. Solid: definite shape and volume
States of Matter
Solid: definite shape and volume
Particles are very tightly packed – incompressible
Difficult to squeeze a solid into a smaller volume
Expands slightly when heated
Most are crystalline – regular, repeating pattern
Other are amorphous – no internal pattern (plastic, glass, gel)

8. Liquid: definite volume, no definite shape
States of Matter
Liquid: definite volume, no definite shape
Particles can move past one another – fluidity
Takes the shape of the container
Expands slightly when heated
Incompressible

9. Gas: no definite volume or shape
States of Matter
Gas: no definite volume or shape
Flows
Expands to fill the volume of the container
Particles are very far apart – compressible
Vapor: used to describe the gaseous state of a substance that is normally a solid or liquid at room temperature (water vapor, mercury vapor)

10. Mixtures of Matter 1. Substance: 2. Mixture:
Substance: matter with uniform – definite composition
Cannot be altered by physical methods
Every sample of a given substance has identical intensive properties because every sample has the same composition
Example: copper
2. Mixture:
Combination of two or more substances in which each retains its individual chemical properties
Heterogeneous and homogeneous

11. Pure Substances Elements: Substance that is composed of
only one type of atom
Building blocks of matter
Cannot be further separated by chemical or physical methods
91 naturally occurring elements
Scientists developed the rest of the elements
Uranium is the largest natural element

12. Elements Origins of name: Periodic Table:
Greek, Latin, or German names based on properties
Location or Scientist of discovery
Commemoration of famous scientist
Periodic Table:
Originally developed by Dmitri Mendeleev in 1869
Altered into current version
Pattern of similar properties repeat

13. Pure Substances Compounds:
Substance that is composed of two or more elements that are combined chemically
Properties of a compound are generally very different from the elements that make it
Chemical Formulas:
Formulas show the symbols on the ratio of the elements in the compound
Subscripts: tell the number of each element in the compound
Ex. C12H22O11

14. Common Compounds Water H2O Glucose C6H12O6 Sucrose C12H22O11
Carbon Dioxide
CO2
Methane
CH4
Ammonia
NH3

15. Heterogeneous Mixture:
Mixtures
Heterogeneous Mixture:
Not uniform in composition
Individual substances remain distinct
Each sample will have parts in different amounts
Ex. Chicken noodle soup, sand in water

16. Mixtures Homogeneous Mixture: Constant, uniform composition
Each sample will have the parts in the same ratio
Ex. Tea, air, saltwater, antifreeze
Solution: another name for homogeneous mixture
Alloy: a solid-solid solution, usually two metals
Ex. Steel and brass

19. Separating Mixtures Filtration:
Mixtures are a physical combination
Separation techniques use differences in physical properties
Filtration:
Used for heterogeneous solid-liquid mixtures
Porous filter paper traps the solid as the liquids pass through
Ex. A colander separates pasta from the water in which it cooked
Distillation:
Used for homogeneous liquid-liquid mixtures
Based on differences in boiling point
Uses condenser
Ex. Alcohol and water

20. Separating Mixtures Crystallization: Chromatography:
Pure solid forms from a solution
Example: rock candy
Chromatography:
Separates components based on relative attraction to two separate phases (mobile and stationary)

21. Law of Conservation of Mass:
Mass is neither created or destroyed in a chemical reaction - it is conserved
Law of Definite Proportions:
Regardless of the amount, a compound is always composed of the same elements in the same proportion by mass
Law of Multiple Proportions:
The same elements can form different compounds by combining in different ratios
CO2 – carbon dioxide
CO – carbon monoxide