Observation - What is evidence? Any observation of Natural Phenomena –Qualitative Use your senses Ex. Texture, color, smell, taste, sound –Quantitative Measured values Ex. Weight, volume, length, temperature Measurements, Verifiable observations, etc. This is how we know what we know!

Organization of Matter Continuous –Aristotle Discontinuous –Democritus ( B.C.) –Dalton (1808) –Joseph Gay-Lussac (1805)

Solid, liquid, and gas states States of Matter David Schultz/Getty Images Water can be found in the solid, liquid, and vapor (gaseous) forms simultaneously.

SOLIDS Highly structured - many are crystalline High degree of interparticle forces

LIQUIDS Not structured - particles flow readily Significant degree of interparticle forces

GASES Not structured - particles flow rapidly Very low degree of interparticle forces

The green color of the Statue of Liberty results from the reaction of copper with the components of air. Andy Levin/Photo Researchers Changes of Matter

"Good" versus "Bad" Properties for a Chemical Substance

Changes of Matter Physical - a change which does NOT alter the composition of a substance. Chemical - a change which alters the composition of a substance.

Physical Change EX. Cutting, breaking, tearing etc. EX. Phase changes EX. Water melts at ~ 0˚C and boils at ~ 100˚C. –Therefore, water is a ______ at 85˚C. –The change of a substance from one phase to another involves either a gain or loss of ENERGY from the system.

Physical Changes of Matter The melting of ice cream is a physical change involving a change of state; solid turns to liquid. Phil Degginger/Color-Pic

(a)A magnet and a mixture consisting of potassium dichromate (orange crystals) and iron fillings. (b) The magnet can be used to separate the iron fillings from the potassium dichromate. Physical Changes

Phase Changes Solid to liquid = Melting Liquid to solid = Freezing Liquid to gas = Vaporization Gas to liquid = Condensation Solid to gas = Sublimation Gas to solid = Deposition

As a result of chemical change, bright steel girders become rusty when exposed to moist air. Chemical Changes of Matter The green color of the Statue of Liberty results from the reaction of copper with the components of air.

Properties & Changes of Matter

Organization of Matter

How could the appearance of each type of chemical change? Outward physical appearance of naturally occurring elements Hg As S Bi I 2 Mg

Laws of Matter Law of Conservation of Mass –Amount of matter does not change during a physical or chemical reaction Law of Definite Proportions –In samples of a chemical compound, the masses of the elements are always in the same ratio Ex. H 2 O Law of Multiple Proportions –Two or more elements may form more than one compound. Ex. H 2 O and H 2 O 2

Studying Matter - Chemistry Requires a scientific approach –Scientific method –Nature of science Requires use of a measurement system and tools for measuring Requires displaying and explaining experimental results –Variables (dependent vs. independent) & controls

Metric System Be able to measure/calculate mass, volume, distance, density & temperature

Measuring Length  The scale on a measuring device determines the magnitude of the uncertainty for the recorded measurement. Include all certain digits plus one uncertain digit in your measurement! –significant (figures) digits (sd)

Volume/Space Liter (L) 1 L = 1 dm 3 Milliliter (mL) 1 mL = 1 cm 3 = 1 cc Microliter (  L) 1  L = 1 mm 3

Measuring Volume Note the type of liquid Indicate which kind of meniscus it is (concave or convex) –Concave: read the bottom of the meniscus (WATER) –Convex: read the top of the meniscus (MERCURY) Include all certain digits plus one uncertain digit in your measurement! –sd

Mass/Weight A gram is defined as the mass of 1 ml of water at 4˚C. Therefore, water has a density of 1 g/mL at 4˚ C.

Measuring Mass Check that the scale is TARED prior to placing anything on it. Include all certain digits plus one uncertain digit in your measurement! –sd

Converting between Measurement Units

Conversions graham crackers = 1 pound cake 2000 mockingbirds = 2 kilomockingbirds

Distance Conversion It is experimentally determined that 1 inch equals 2.54 cm, or 1 cm equals inch