Describing Matter
Properties:
1) Extensive – depends on amt of matter in sample
- ex’s. mass, volume, calories, magnetism
2) Intensive – depends on type of matter, not amt.
Hardness, Density, B.P.
All samples of same substance have same intensive prop’s. (same composition)

Identifying Substances


Physical Properties - observed & measured w/o changing composition
◦color, hardness, m.p., b.p.
Chemical Properties - observed by changing comp of material
◦ability to burn, decompose, ferment, react w/, etc.

States of matter
1) Solid - cannot flow (definite shape & volume)
2) Liquid - definite vol - takes shape of container (flows)
3) Gas - w/o definite vol or shape & flows
◦ Vapor - gaseous but normally liquid or solid @ room temp
 water “gas”, or water “vapor”?

Three Main Phases – page 41

Definite
Volume?
Definite
Shape?
Result of a
Temperature
Increase?
Will it
Compress?
Solid YES YES
Small
Expans.
Not easily
Liquid
YES
NO
Small
Expans.
Not easily
Gas
NO
NO
Large
Expans.
YES

4 th state:
formed at hi temps; ionized phase of matter
(Sun)

Freeze
Melt
Sublime
Condense
Evaporate
Solid Liquid Gas

Physical vs. Chemical Change



Physical change changes visible appearance w/o changing comp of material
◦ Boil, melt, cut, bend, split, crack
◦ Is boiled water still water?
Reversible, or irreversible
Chemical change - change where new substance formed
◦ Rust, burn, decompose, ferment

Section 2.2 Mixtures p. 44

Mixture - physical blend of 2+ components
1) Heterogeneous – uniform in comp
• Choc chip cookie, gravel, soil
2) Homogeneous - same comp thruout
(solutions)

• Kool-aid, air, salt water
Every part keeps own prop’s

Solutions - homogeneous mixtures


Mixed molecule by molecule, so too small to see diff pts occurs btwn any state of matter: gas-gas; liquid-gas; gas-liquid; solid-liquid; solid-solid (alloys)
◦ Steel (Fe, Cr & Ni)





“phase” describes any pt of sample w/ uniform comp of properties
A homogeneous mixture consists of a single phase
A heterogeneous mixture consists of two or more phases.
Note Figure 2.6, page 45

Separating Mixtures



Some by physical means: rocks & marbles, iron filings & sulfur (magnet)
Differences in physical props used to separate mixtures
Filtration - separates solid from liquid in hetero mix. (by size) –
Figure 2.7, page 46

Distillation: takes advantage of different boiling pts.
NaCl boils at 1415 o C
H
2
O boils at 100 o C
Mg boils at 1107 o C

Components of dyes such as ink may be separated by
.
Forensic Ink Analysis
Chromatography video

Applications of Chromatography





2 Greek words:
◦ chroma "color" and “graphein "to write"
Biological labs:
◦ ID amino acids
◦ detects drugs in urine
Environmental labs:
◦ ID contaminants in waste oil
◦ pesticides in groundwater
◦ test drinking water & test air quality
Pharmaceutical companies
◦ prepare quantities of extremely pure materials.
Food industry
◦ ID contaminants like aflatoxin
 naturally occurring toxin produced by fungus

Pure
Substances
Element Compound
Simplest matter
1 type of atom
Cannot be broken down
Broken down by different prop’s than chemical elements methods
2+ atoms chemically combined

Compounds v.s. Mixtures
Compounds Mixtures
Made of one kind of material
Made by a chemical change
Definite composition
Made of more than one kind of material
Made by a physical change
Variable composition

Which is it?

A “chemical change” chg producing matter w/ diff. comp than original matter
1+ substances are converted into different substances.
&
often indicate chem chg

Classification of Matter






118 elements
1 - 2 letter symbol
1 st letter CAP; 2 nd letter lowercase
◦ B, Ba, C, Ca
Some names Latin
◦ Table 2.2, page 52 cmpds have formula
◦ H
2
O, NaCl, C
12
H
22
O
11

Sec 2.4 Chemical Rxns p. 53
Chemical Changes


Chemical property - ability of substance to undergo specific chem change
• Fe + O = rust
• rusting - chem prop of Fe
During chem chge comp of matter always changes


Chemical Rxns are…
When 1+ substances changed into new substances

Reactants - start w/



Products - end w/
Products have NEW PROPS diff from reactants
Arrow points from reactants to new products

Recognizing Chemical Changes
1) Energy absorbed/released (temp changes hotter/colder)
2) Color changes
3) Gas production (bubbling, fizzing, or odor change; smoke)
4) precipitate forms - solid separates from solution (won’t dissolve)
5) Irreversibility - not easily reversed
Some ex’s not chem – boiling water bubbles, choc syrup in milk, etc.

Conservation of Mass



During any chem rxn, product mass = reactant mass
All mass accounted for:
◦ Burning wood results in products that appear to have less mass (ashes)….
◦ CO
2
& H
2
O vapor

- Page 55
43.43 g Original mass = 43.43 g Final mass reactants = product