Unit 1
The Science of Chemistry and Matter
 What is Chemistry?
Energy
Elements
Laboratory
Compounds
 Discuss with the person next to you different ways you
think chemistry is present in your everyday life.
Classification of matter
Objectives:
1.
2.
3.
4.
5.
6.
7.
Relate chemistry to everyday life.
Identify traditional areas of study in chemistry.
Define matter.
Categorize samples of matter as a mixture or a substance.
Distinguish between homogeneous and heterogeneous
mixtures.
Describe ways components of a mixture can be separated
Explain the difference between a compound and an
element.
 Chemistry is the study of the composition of matter
and the changes matter undergoes.
 Matter: anything that has mass and occupies space.
 There are five traditional areas of study for chemistry
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Organic chemistry: study of chemicals containing carbon.
Inorganic chemistry: study of chemicals that do not contain
carbon.
Biochemistry: study of processes that take place in
organisms.
Analytical chemistry: focuses on composition of matter
Physical chemistry: describes behaviors of chemistry.
 Chemistry far and wide:
 Materials: plastic, glass, ceramics, perfumes, food, etc.
 Energy: fossil fuels, food, solar batteries, nuclear
 Medicine: penicillin, aspirin, Vitamin C
 Agriculture: fertilizer, pesticides, growth hormones
 Environment: ozone, carbon dioxide- global warming,
pollution
 Astronomy: composition of planets and stars
 Classification of matter
 Mixtures: a physical blend of two or more components.
Ex. Salad, pizza, milkshake and air
 Heterogeneous mixtures: the composition is not
uniform
 Homogeneous mixtures: composition is uniform
throughout. Also called solutions.
 In a solution we have a solute (substance being
dissolved) and a solvent (substance dissolving solute)

Water is the universal solvent
 Most are liquids
 Some are solids. Example alloys of different metals like
brass, an alloy of copper and zinc.
For tomorrow research what other types of alloys
we use.

 Some are gases like the air
Figure 1.4a
MIXTURES
HOMOGENOUS
HETROGENOUS
 Pure Substances: have fixed composition.
 Elements are the simplest form of matter that has its
unique set of properties.
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Ex. Gold is an element. All atoms of gold have the same
properties.
Elements are shown in the Periodic Table.
There are more than 100 elements, most of them occur
naturally.
Elements are represented by one (a capital letter) or two letter
symbols(a capital letter and a lowercase letter).
Ex. C: carbon
Co: cobalt
 Compounds is a substance that contains two or more
elements chemically combined in a fixed proportion.


Represented by chemical formulas using symbols of elements
present in compound and subscripts indicated how many
atoms of each element is present.
Ex. H2O: water CO: carbon monoxide CO2: carbon dioxide
 Learning Check:
1.
How do elements relate to compounds?
2. How do elements and compounds relate to mixtures?
3. What is the main difference between pure
substances and mixtures?
 Learning Check:
1. How do elements relate to compounds? Compounds are
made from elements chemically combined.
How do elements and compounds relate to mixtures?
Elements and compounds physically combine to form a
mixture.
3. What is the main difference between pure substances and
mixtures?
Pure substances have a fixed composition and the
composition of mixtures may vary.
2.
Classwork: p53 #1-3
HW: Bring tomorrow any sample of
matter and share with the class how
you would classify the sample and why.
Separation of mixtures
• Separate mixtures based on different
physical properties of the components
Different Physical Property
Technique
Boiling Point
Distillation
State of Matter (solid/liquid/gas)
Filtration
Adherence to a Surface
Chromatography
Volatility
Evaporation
Density
Centrifugation &
Decanting
Distillation
Filtration
Breaking down compounds
 Methods used to separate mixtures can not
be used to break compounds into simpler
substances.
 To break down compounds, a chemical
change has to occur which produces matter
with a different composition than the
original matter.
Changes in matter
1.
2.
3.
4.
5.
Identify properties as extensive or intensive.
Define a physical property and a chemical property.
Describe a physical change.
Describe what happens during a chemical change.
Identify clues that a chemical change has taken
place.
 Changes in matter
 Physical change : same substance remains after the
change.
 Ex. Pounding, cutting, dissolving
 Changes of state: melting, boiling, condensing, etc.
 Ex. Evaporating water from sea water to get salt.
 Chemical change: a new substance appears after the change. New
substance has different characteristics. (a chemical reaction)
 Evidence of chemical change
 Production of gas (observed as bubbles or change of odor)
 Release or absorption of energy (change in temperature or giving
off light)
 A color change
 Formation of a precipitate (solid formed when two clear solutions
combine and become cloudy)
 Ex. Burning, digestion, fermentation
 During a chemical reaction, the mass of
products is equal to the mass of the
reactants: law of conservation of mass.
 Physical property: quality of a substance that can be
observed or measured without changing the
substance’s composition. Ex. Length, color,
temperature
 Extensive: depend on the amount of matter present. Ex.
Mass, length, volume
 Intensive: do not depend on the amount of matter
present. Ex. Density, color, malleability (can be
hammered), ductility (can be turned into wires),
conductivity, melting point.
 Chemical property : describes the behavior of a
substance undergoing a chemical change. Describes
how it reacts with other materials like air, water, and
acids.
 Characteristics could be: acidity, flammability, reactivity,
oxidizing ability, explosiveness.
 Ex. iron + oxygen  rust
 Indicating it does not react is also a chemical property.
 Learning check:
1.
Classify the following as a chemical or physical property
a.
b.
c.
d.
e.
2.
Is red
Reacts with water
Boils at 88C
Dissolves in gasoline
Is corrosive
Classify the following as a chemical or physical change
a.
b.
c.
d.
e.
Alcohol evaporating
An explosion
Digesting food
Salt dissolving in water
Grass growing
 Learning check:
1.
Classify the following as a chemical or physical property
a.
b.
c.
d.
e.
2.
Is red
Reacts with water
Boils at 88C
Dissolves in gasoline
Is corrosive
physical
chemical
physical
physical
chemical
Classify the following as a chemical or physical change
a.
b.
c.
d.
e.
Alcohol evaporating physical
An explosion
chemical
Digesting food
chemical
Salt dissolving in water physical
Grass growing
chemical
 Energy and change
 Energy is the capacity to do work. Always involved when there is a
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change in matter.
Endothermic and exothermic processes
 Endothermic: energy is absorbed from the surroundings. (Ex.
Boiling water)
 Exothermic: energy is released to the surroundings. (Ex. fire)
Law of conservation of energy: during a physical or chemical
change, the total quantity of energy remains the same.
Energy can be released or absorbed as heat.
Kinetic energy: energy of motion
Temperature: measurement of average kinetic energy of the random
motion of particles in a substance.
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Units: Celsius(C), Kelvin (K)
Zero in the Kelvin scale is called the absolute zero.
K= C + 273
 Classwork: pg 62 #6-8
Unit 1
The Science of Chemistry and Matter