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)