Transcript Chemistry: the study of composition, structure, and properties of

Chemistry: the study of
composition, structure, and
properties of matter* and the
changes it undergoes.
*Matter: composed of mass and takes up space.
Elements and Compounds
•
•
•
All matter is composed of atoms.
– Copper pipe is made of copper atoms.
– Oxygen gas is made of oxygen atoms.
An element is a pure substance made of only one kind of
atom.
– Carbon is an element made of only carbon atoms.
Atoms of two or more elements bond together to make
compounds.
– CO2 (___ carbon atom and ___ oxygen atoms)
– H2O2 (___ hydrogen atoms & ___ oxygen atoms)
Chemical
Formulas
C6H12O6
6 Oxygen atoms
12 Hydrogen atoms
6 Carbon atoms
Classification of
Matter
Mixtures
Pure Substances
Homogeneous Heterogeneous
Compounds
Elements
(air, sugar in water)
(water, salt, sugar)
(gold, oxygen)
“Solutions”
(wood, blood)
Mixtures vs. Pure Substances
MIXTURES
• Blend of two or more
types of matter (each
retains its own identities
and properties.)
• Sugar-Water…is both
sugar and water. Tastes
like sugar and tastes like
water.
• Examples: grape juice
(water and sugar)
PURE SUBSTANCES
• Every sample has
exactly the same
properties and came
composition.
– Pure water is always
11.2% hydrogen and
88.8% oxygen.
Homogeneous vs. Heterogeneous
Mixtures
Homogeneous
• The same throughout…
every part is evenly
distributed.
• Examples:
Heterogeneous
• Not the same
throughout… every part is
not evenly distributed.
• Examples:
– vinegar (water and acetic
acid)
– Salad (tomatoes, lettuce,
olives, carrots, etc.)
“HOMO” : the same
“HETERO” : different
Making a Mixture: “Mixing”
Miscible: able to be mixed (liquids only)
EX. Gasoline is a mixture of about 100 liquids.
Immiscible: not able to be mixed (liquids only)
EX. Oil and water cannot mix.
Gases can mix with liquids also. An example is a
carbonated drink like Pepsi.
CO2 + sugar + water + flavorings + Awesome Pepsi
Separation of Mixtures
DISTILLATION
FILTRATION
1. Boil mixture.
1. Pour mixture onto a mesh,
like filter paper.
2. Liquid boils off, leaving solid
minerals behind.
2. Liquid passes through
paper.
3. Collect the boiled vapor in a
condenser.
3. Solid is left on the paper.
4. Collected liquid is pure(er).
Ex: Coffee filters
Ex: Seawater
Physical Properties
A characteristic that can be observed or measured without
changing the identity of the substance.
Examples: boiling and freezing points
Physical Change: does not involve a change in identity of the
substance…cutting, melting, boiling, freezing, dissolving.
Change of State: physical change from one state to another.
• Solid  Liquid (Melting)
Liquid  Solid (Freezing)
• Solid  Gas (Subliming)
Gas  Solid (Deposition)
• Liquid  Gas (Evap./Boil) Gas  Liquid (Condensing)
SOLID - LIQUID - GAS
- PLASMA
Physical Properties
Other Physical Properties Include:
- strength
- hardness
- magnetism
- reflectivity
- melting point (temp at which it boils)
- melting point (temp at which it melts)
- density
What is Density?
Density: a measurement of
how much matter is
contained in a certain
volume.
Calculate Density
D =
Mass
Volume
M
D
V
***Test: Density of Water: 1.00 g/mL
Density Practice Problems
1.
2.
3.
4.
5.
Mass (g)
2.0
0.6
?
5.0
2.3
Volume (mL)
1.0
2.0
2.5
?
?
Density (g/mL)
?
?
4.5
1.0
5.0
Density Practice Problems
1.
2.
3.
4.
5.
Mass (g)
2.0
0.6
11.3
5.0
2.3
Volume (mL)
1.0
2.0
2.5
5.0
0.5
Density (g/mL)
2.0
0.3
4.5
1.0
5.0
Density Practice Problems
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
Mass (g)
1.00
2.45
5.11
6.02
0.75
?
?
4.00
5.55
35.02
Volume (mL)
2.00
3.10
2.11
1.35
1.75
1.50
0.25
?
?
?
Density (g/mL)
?
?
?
?
?
4.01
0.65
3.00
2.22
6.01
Density Homework Problems
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
Mass (g)
3.00
2.30
1.11
27.25
0.35
?
?
8.02
5.00
31.07
Volume (mL)
3.00
4.11
6.22
11.35
1.25
1.10
0.47
?
?
?
Density (g/mL)
?
?
?
?
?
4.10
0.75
3.02
2.04
7.23
Weight vs. Density
Density: a measurement of
how much matter is
contained in a certain
volume.
Weight: the measurement
of gravity on an object’s
mass…”how heavy”.
Physical States of Matter
• SOLID:
– Definite Shape
– Definite Volume
– Particles move slowly
and are close together
• Examples
– Sodium metal (Na)
– Ice (H2O)
– Gold at room temp. (Au)
Physical States of Matter
• LIQUID:
– No Definite Shape
– Definite Volume
– Particles move a little
faster than solids and
more freely.
• Examples
– Mercury (Hg)
– Water (H2O)
– Gold at high temp. (Au)
Physical States of Matter
• GAS:
– No Definite Shape
– No Definite Volume
– Particles move very quickly and
are far apart.
• Examples
– Neon (Ne)
– Steam (H2O)
– Chlorine gas (Cl2)
Physical States of Matter
• PLASMA:
– High Temperature
– Atoms lose electrons
easily
• Examples
– Sun
– Fluorescent Bulbs
Chemical Properties…
…relate how chemicals undergo change.
Chemical Change (reaction): when substances
are converted into NEW substances.
Reactants REACT. Products are PRODUCED.
reactant + reactant  product
carbon + oxygen  carbon dioxide
C + O2  CO2
Chemical Properties…
…relate how chemicals undergo change.
Other Chemical Properties Include:
- Reactivity (how readily a reaction will occur)
- Flammability (ability to burn)
- Tarnishing
- Reacting with water, oxygen, acids, bases…
Chemical Changes
…can be detected.
Indications of a
Chemical Reaction:
1. Change in odor or color.
(burnt food)
2. Fizzing or Foaming
(Alka-Seltzer)
3. Sound, heat, or light
(TNT)
Review
P. 70-71 (Questions 1 – 21; 24 – 27)
- Do not write the question. Just the answer.
- Vocabulary on p.69 will be on the test.