intro chemistry

2. What is Chemistry?
 The study of the composition of
matter and the changes that
matter undergoes.
 Living and nonliving things are
made of matter, chemistry affects
all parts of life and most natural
events.

3. Areas of Study
 Organic Chemistry- The study of all chemicals containing carbon.
 Inorganic Chemistry- Study of chemicals that do not contain
carbon.
 Biochemistry- Focuses on processes that take place in organisms.
 Analytical Chemistry- The study that focuses on the composition of
matter
 Physical Chemistry- Deals with the mechanism, the rate, and the
energy transfer that occurs when matter undergoes a change.

4. Pure and Applied Chemistry
• Pure Chemistry- the pursuit of chemical
knowledge for its own sake.
• Applied Chemistry- research that is
directed toward a practical goal or
application.
Nylon and Aspirin are examples of the two.

5.  Chemists use specific materials to meet
specific needs.
 Macroscopic- describes the world of
objects that are large enough to see with
the unaided eye
 Microscopic- world of objects that can
be seen only under magnification.

6. Scientific Method- a logical, systematic approach to the
solution of a scientific problem. Steps in the
scientific method include making observations,
testing hypotheses, and developing theories.
Hypothesis - is a proposed explanation for an
observation. A hypothesis is useful only if it accounts
for what is actually observed. When experimental
data does not fit a hypothesis, the hypothesis must
be changed.
Experiment - a procedure that is used to test a
hypothesis.
When you design experiments, you deal with variables,
or factors that can change. The variable that you
change during an experiment is the manipulated
variable, or independent variable. The variable
that is observed during the experiment is the
responding variable, or dependent variable

7. Describing Matter
 Properties used to describe matter can be
classified as extensive or intensive.
 Mass of an object- is a measure of the amount of
matter the object contains.
 Volume of an object- is a measure of the space
occupied by the object.
 Extensive property- is a property that depends on
the amount of matter in a sample.
 Intensive property- is a property that depends on
the type of matter in a sample, not the amount of
matter.

8. Identifying Substances
 Substance- Matter that has a uniform and
definite composition.
 Physical property- is a quality or
condition of a substance that can be
observed or measured without changing
the substance’s composition.

9. States of Matter
Three states of matter are solid, liquid, and gas.

10.  Solid- a form of matter that has a definite
shape and volume. The shape of a solid
doesn’t depend on the shape of its container.
The particles in a solid are packed tightly
together, often in an orderly arrangement.
Solids are almost incompressible; that is, it is
difficult to squeeze a solid into a smaller
volume.
 Liquids- take the shape of the container in
which it is placed. Volume of a liquid is fixed
or constant. A form of matter that has an
indefinite shape, flows, yet has a fixed
volume. Liquids are almost incompressible,
but they tend to expand slightly when
heated.

11.  Gas- a form of matter that takes both the
shape and volume of its container.
Particles in a gas are usually much farther
apart than the particles in a liquid.
Because of the space between particles,
gases are easily compressed into a smaller
volume.
 Vapor- describes the gaseous state of a
substance that is generally a liquid or
solid at room temperature, as in water
vapor.

12. Physical changes- some
properties of a material
change, but the
composition of the
material does not change.
Physical changes can be
classified as reversible or
irreversible. Melting is an
example of a reversible
physical change.
Words such as boil, freeze,
melt, and condense are
used to describe physical
changes.

13. Classifying Mixtures
 Mixture - is a physical blend of two or more
components. Mixtures can be classified as
heterogeneous mixtures or as homogeneous
mixtures.
 Heterogeneous mixture - a mixture that is not
uniform in composition, components are not evenly
distributed throughout the mixture.
 Homogeneous mixture - is a mixture in which the
composition is uniform throughout. Another name
for a homogeneous mixture is a solution. Many
solutions a liquids, some are gas and some are
solids.
Phase is used to
describe any part of
a sample with
uniform composition
and properties. By
definition, a
homogeneous
mixture consists of a
single phase. A
heterogeneous
mixture consists of
two or more phases.

14. Separating Mixtures
 The process that separates a solid from
the liquid in a heterogeneous mixture is
called filtration.
 Distillation- a process used to separate
dissolved solids from a liquid, which is
boiled to produce a vapor that is then
condensed into a liquid

15. Distinguishing Elements
and Compounds
 Element- the simplest form of matter that
has a unique set of properties, an element
cannot be broken down into simpler
substances by chemical means.
 Compounds- contain two or more
elements chemically combined.
Compounds can be broken down into
simpler substances elements can not.
Compounds can be broken down into simpler
substances by chemical means, but elements
cannot.

16.  Chemical change is a change that produces
matter with a different composition than the
original matter. Heating is one of the processes used
to break down compounds into simpler substances.

17. Chemical Changes
 Chemical property- The ability of a
substance to undergo a specific chemical
change. During a chemical change, the
composition of matter always changes
 Chemical Reaction- One or more
substances change into one or more new
substances.
 A substance present at the start of the
reaction is a reactant.
 A substance produced in the reaction is a
product.

18. Scientific Measurement
Ch. 3

19.  Measurement: is a quantity that has both a
number and a unit. Everyone makes and uses
measurements.
 scientific notation: a given number is
written as the product of two numbers: a
coefficient and 10 raised to a power. For
example, the number
602,000,000,000,000,000,000,000written in
scientific notation is 6.02 × 1023
 Accuracy: is a measure of how close a
measurement comes to the actual or true
value of whatever is measured.
 Precision: is a measure of how close a series
of measurements are to one another.

20.  The percent error is the absolute value of
the error divided by the accepted value,
multiplied by 100%.
 There is a difference between the
accepted value, which is the correct value
based on reliable references, and the
experimental value, the value measured
in the lab. The difference between the
experimental value and the accepted
value is called the error.