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Chapter 2 Notes
1
CHAPTER 2
Matter and Change
2.1 PROPERTIES OF MATTER
• EXTENSIVE PROPERTY:• Depends on the amount of matter
in a sample• Comparing the same substances.• Diamonds to Diamonds
INTENSIVE PROPERTY:
• Depends on the type of matter in a sample, not the amount of matter
• Comparing different substances.• Diamonds to Cubic Zirconium
IDENTIFYING SUBSTANCES• Matter: anything that has mass and takes
up space. (Has atoms...)• Substance: a particular kind of matter that
has a uniform and definite composition• Mass: measures the amount of matter in a
substance• Energy is NOT matter!
THE STATES OF MATTER
• Solid• Liquid• Gas (vapor)
Chapter 2 Notes
2
SOLIDS
• Definite Shape• Definite Volume• Not easily compressed
LIQUIDS
• Indefinite shape > (Takes the shape of it’s container)
• Definite Volume• Not easily compressed
GASES• Indefinite Shape • (Takes shape of it’s container)
• Indefinite volume• Easily compressed• Vapor is a gas that is liquid or solid at room temperature.
Solids Liquids Gases
Definite Shape
Definite Volume
Not easily compressed
Indefinite Shape
Definite Volume
Not Easily Compressed
Indefinite Shape
Indefinite Volume
Easily Compressed
PHYSICAL CHANGES
• Alter substances without changing its composition
• Boil, freeze, dissolve, melt, condense, break, split, crack, crush
Chemical Changes
. Chemical Rxn
Change in Chemical composition
C6H12O6 + 6O2 6H2O + 6CO2
Chapter 2 Notes
3
2.2 MIXTURES
• A physical blend of two or more substances • Heterogeneous: Different throughout
(Pepper Water)• Homogeneous: Same throughout
(Sugar Water)> Solution = dissolved salt or sugar in water
NOT A CHEMICAL CHANGE
Separating MixturesFiltration: Filtering solutions to remove the
solid or undissolved portion.Distillation: Heating a solution to remove
the dissolved portion
* Not a Chemical Reaction!
Filtration Distillation
Distilled Water
What does Physical State mean?• Shape of substance• Fine powder, crystals, coarse, etc.• Color of the substance Record your observations?• There was a color change.• Gas bubbles were produced.• There was a temperature change• Nothing happened.• It exploded...
Recognizing Chemical Changes
• Transfer of Energy (Heat, Light)• Change in color (Rust, ashes)• Gas formation (H2, Water vapor, CO2)• Formation of precipitate
(A solid forms from two liquids)
What is a chemical formula?
Chapter 2 Notes
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• Elements: simplest forms of matter than can exist under normal conditions
• Compounds: can be separated into simpler substances only by a chemical reaction
• Chemical vs. Physical properties
2.3 ELEMENTS AND COMPOUNDS
• Compounds are Pure• Uniform throughout• Atoms must be bonded together• Only separated by chemical means.• 2NaCl + Mg à MgCl2 + 2Na
Pure Substances
Pure Substances
Elements consists of only 1 type of atom
Compounds consists of 2 or
more different atoms bonded together
Pure or ImpureH2O
O2
Mg
CaCl2
NaCl+
H2ONa+Mg
O2+N2
Sand+
H2O
Impure SubstancesMixtures
Salt WaterSugar Water
AirMilkBlood
Alloys
Steel: iron, carbon14K Gold: Gold, Antimony, copperBronze: copper, tinBrass: Copper, zincPewter: tin, copper, antimony
Chapter 2 Notes
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SYMBOLS AND FORMULAS
• Each element is represented by a chemical symbol
2.4 CHEMICAL REACTIONS• One or more substances change
into new substances• Reactants• Products *complete rearrangement of atoms.
N2 + 3H2 à 2NH3
Parts of a Chemical Reaction
Reactants Products
Physcial vs. ChemicalPhysical Properties
ColorOdorMelting PointBoiling PointMalleability (Bending)HardnessTexture
DissolvingChemical Properties
Does it burn?Does it react?Does it rust?
Recognizing Chemical Changes
• Transfer of Energy (Heat, Light)• Change in color (Rust, ashes)• Gas formation (Water vapor, CO2)• Formation of precipitate
(A solid forms from two liquids)
Chapter 2 Notes
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PHYSICAL CHANGES
• Alter substances without changing its composition
• Boil, freeze, dissolve, melt, crush,condense, break, split, crack
• Separated into simpler substances only by a chemical reaction
• Below: The compound, HCl, is separatedby reacting with Mg.
• HCl + Mg à MgCl2 + H2
COMPOUNDS
CONSERVATION OF MASS
• THE LAW OF CONSERVATION OF MASS mass is neither created nor destroyed
CONSERVATION OF MASS• If 16 grams of CH4 reacted with 64 grams of
O2, how many grams of H 2O are released if 44 grams of CO2 are produced?
• CH4 + O2 CO2 + H2O