Transcript Chapter 1 Matter, Energy, and Changex

Matter, Change,
and Energy
Chemistry - The study of composition
of matter and the changes
that matter undergo.
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Matter, Change,
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5 Major Divisons of Chemistry
I.
Organic Chemistry
–
IV. Physical Chemistry
–
V. Biochemistry
–
The study of materials that contain
carbon.
II. Inorganic Chemistry – The study of materials that do not
contain carbon.
III. Analytical Chemistry – Concerned primarily with the
composition of substances.
Specializes in the discovery and
description of chemical substances.
The study of the composition and
changes in composition of living
organisms.
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The Scientific Method
* The scientific method incorporates
observations, hypotheses, experiments,
theories, and laws.
Observations - scientist make observations when
they note and record facts about natural
phenomena.
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Matter, Change,
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The Scientific Method
* The scientific method incorporates
observations, hypotheses, experiments,
theories, and laws.
Hypothesis - a possible explanation or descriptive
model used to explain the observation
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Matter, Change,
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The Scientific Method
* The scientific method incorporates
observations, hypotheses, experiments,
theories, and laws.
Experiments - procedures performed to test a
hypothesis where at least one condition is
controlled.
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Matter, Change,
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The Scientific Method
* The scientific method incorporates
observations, hypotheses, experiments,
theories, and laws.
Theories - thoroughly tested models that explain
why experiments give certain results.
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Matter, Change,
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The Scientific Method
* The scientific method incorporates
observations, hypotheses, experiments,
theories, and laws.
Laws - a fact or concise statement that
summarizes a broad variety of observations.
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Matter, Change,
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Properties ofmelting
Matter
evaporation
* Matter is anything that has mass and
takes up space. The amount of matter that
an object contains is its mass.
freezing
condensation
liquids
gases
have
theaavolume
definiteof
volume
theirand
container
buta take
the
andvolume.
shape
take the
of
Solids ––– fill
have
definite
shape
definite
their
shapecontainer.
of their container.
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Matter, Change,
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sublimation
Vapor – describes a substance that although is in the gasesous
state, it’s generally a solid or liquid at room temperature.
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States of Matter
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Matter, Change,
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Matter is described by “properties”.
Physical Property – a quality or condition of a substance
that can be measured without changing the chemical
composition of the substance.
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Matter is described by “properties”.
Chemical Property – describe the changes that occur in a
material when it becomes a new substance via chemical
reaction..
The rusting of iron to become
iron oxide is an example of a
chemical change.
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Matter is described by “properties”.
When ice melts it still remains the same chemically, H2O
This is an example
of a physical change.
Matter, Change,
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Mixtures
A mixture consist of a physical blend of two or
more substances.
Heterogeneous
Homogeneous
* Does not have
* A tossed salad has
uniform composition so
distinct layers so it’s
distinct layers are
heterogeneous
visible.
• •Toothpaste
has a
Has a uniform
uniform
compositon
composition
is the
and NO
distinct
layers,
same
throughout.
so it’s homogeneous.
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Mixtures
Each distinct layer in a
heterogeneous mixture
Is called a phase.
The boundary between
Each phase is called
an interface.
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Mixtures
Homogeneous mixtures
are uniform
throughout.
They consist of one
phase.
Homogeneous mixtures are called solutions.
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Mixtures
One way to separate a
homogeneous mixture
such salt water into
Its component
substances is through
a process called
distillation.
Diagram of simple distillation set-up without a
fractionating column often used by chemists.
Shown in use.
1. heat source (a Bunsen burner here)
2. distilling flask (a round bottom flask)
3. distilling head
4. thermometer
5. condenser
6. cooling water in
7. cooling water out
8. receiving flask collecting dripping distillate
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Chemical Change
Carbon + Water
Elements
Cane Sugarand Compounds
(compound)
(element)
(compound)
• Every substance is an element or a compound.
Element - The simplest form of matter that can
exist under laboratory conditions.
Compound – Hydrogen
made of two +
or more
elements.
Oxygen
Compounds
separated into
(element) can be(element)
simpler substances ONLY by chemical
reactions.
Matter, Change,
and Energy
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Matter
Substance
definite composition
ELEMENT
COMPOUND
Mixture of substances
variable composition
HOMOGENEOUS
MIXTURE
HETEROGENEOUS
MIXTURE
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Chemical Symbols
Each element is represented by a chemical symbol.
Example: H = Hydrogen ; O = Oxygen
Chemical symbols can be combined to make chemical
formulas.
Example: H2O = water
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Energy
Energy is the ability or “capacity” for doing work.
Nearly all chemical and physical changes in nature involve
the absorption or emission of energy.
Energy can exist in several forms:
Ex: Nuclear ; Chemical ; Radiant ; Thermal ; and Mechanical
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Energy
Green plants survive by storing chemical energy.
Stored chemical energy is called potential energy.
gasoline
Gasoline has stored potential
energy. When it’s “burned”
in a car motor, the chemical
potential energy of the
is converted to
kinetic energy.
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Law of Conservation of Energy
The law of conservation of energy states that energy can
not be created nor can it be destroyed. However it can
change forms.
Just as energy is required to “fuel” a vehicle, energy is
also required to “fuel” chemical reactions. Remember, a
chemical reaction can never create nor destroy energy.
Matter, Change,
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Chemical Reactions
In a chemical reaction, one or more substances are
changed into a new substance.
Heat energy
Iron + Sulfur
Reactants
Products
Iron sulfide