Chemistry Intro. Notes
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Transcript of Chemistry Intro. Notes
Chemistry Intro. Notes
Chemistry –Matter –Mass –Weight – Volume -Energy – Kinetic – Potential –
Study of matter and energy
All of the “stuff” in the universeA quantity or amount of
matterMass with a force or attraction like gravityA measurement of the space something
occupiesAbility to do work
Energy of motion
Energy of position
Chemistry Intro. Notes cont…
Observation – Quantitative – Qualitative -
Hypothesis -Theory –Law –
Perceiving using the 5 sensesAn observation using numbers AND units (measurement)An observation using the senses
(hard to quantify exa..green)Educated guess made after observationsPossible explanation of a law
A statement about nature to which there are NO known exceptions
Exa…the sun rises in the east and sets in the westScientific Method:
Observation
Hypothesis Experiments
Theory
Chemistry Intro. Notes cont…
MatterMixtures Pure Substances
(Homogeneous)-Separated by physical means
-Separated by chemical means
Heterogeneous
Homogeneous
-unevenly
distributed
-evenly
distributed
(solution)
Element
(symbol)
-every piece is the same type of atom (p.t.)
-Exa… Al foilatom
Protons Neutrons
ElectronsQuark Quark
Compound
(formula)
-2 or more atoms chemically combined
covalentmolecules
(non-metals)
ionic
Ions
(metal ion +
Non-metal
ion)
Physical Properties
Physical Property –
Examples:
Defines the physical nature of the substance
•Color * Volume * Freezing point
•Texture * Taste * Sublimation point
•Size * Boiling point
•Odor * Evaporation point
•Density * Condensation point
•Sound * Melting point
Physical Changes
Physical Changes –
Example: …for water (H2O)
A change without change of identity
Melting Point Boiling Point
Solid LiquidGas
Freezing Point Condensation Point
O °C 1OO °C
Chemical Properties
Chemical Properties –
Examples:* flammable (combustible) –
* oxidizer – * reactive –
* corrosive – * explosive -
Define the chemical nature of the substance
will burn
Will combine with oxygen (exa…rust)Will create bubbles while chemically changing (exa…with acids and bases)Will eat away by chemical action (exa..acids and bases)Will produce a rapid chemical change with a violent burst of energy
Chemical Changes
Chemical change – Evidence of a Chemical change:1.
2. 3. 4. 5. 6. 7. 8.
Change with change of identity
Light
Odor Change
Color change (careful!! This can be physical!)
Precipitate ie “chunky stuff” (filtration)
Reaction, gas given off (NOT dissolving)
Taste Change
Appearance change
Heat Change
Endo/Exo NotesA symbol represents an ___________A formula represents a _____________________ represents a chemical changeexa… A + B C + D
exa… iron + sulfur iron (II) sulfide
Law of Conservation of Matter -
Element
Compound
Equation
Reactants Products
Fe + S FeS
Matter cannot be created nor destroyed.
(It just changes places)
Exo/Endo Notes cont…
There are 2 kinds of Energy Changes in a chemical reaction:
1) Exothermic –
2) Endothermic –
Energy “exits” (goes out)
Exa… X + Y Z+ Energy
Energy “enters” (goes in)
Exa… A + B CEnergy +
Exo/Endo Notes cont…
Chemical Change* Think about
Hot/Cold!1) Exothermic
2) Endothermic
Physical Change* Think about
ENERGY!1) Exothermic
2) Endothermic
HOT
-energy given off
COLD
-energy absorbed
H2O (l) H2O (s) + Energy or
H2O (g) H2O (l) + Energy
Energy + H2O (l) H2O (g) or
Energy + H2O (s) H2O (l)