Chemistry Unit 1 PPT 1

Chemistry
Toombs County High School

What Is Chemistry?
 Why is the scope of chemistry so vast?
1.1

 Matter is anything that has mass and
occupies space.
 Chemistry is the study of the composition
and properties of matter and the changes
that matter undergoes.
1.1

Because living and
nonliving things are made
of matter, chemistry
affects all aspects of life
and most natural events.
1.1

Areas of Study
What are five traditional
areas of study in
chemistry?
1.1

Five traditional areas of study are
▪organic chemistry
▪inorganic chemistry
▪biochemistry
▪analytical chemistry
▪physical chemistry
1.1

Organic
chemistry is
defined as
the study of
all chemicals
containing
carbon.

Inorganic chemistry is
the study of chemicals
that, in general, do not
contain carbon.

The study of
processes
that take
place in
organisms is
biochemistry
.

Analytical
chemistry is
the area of
study that
focuses on
the
composition
of matter.

Physical chemistry
is the area that deals
with the mechanism,
the rate, and the
energy transfer that
occurs when matter
undergoes a change.

Pure and Applied Chemistry
How are pure and applied
chemistry related?
1.1

Pure chemistry is the pursuit of
chemical knowledge for its own
sake.
Applied chemistry is research that
is directed toward a practical goal or
application.
1.1

Pure research can lead directly to
an application, but an application
can exist before research is done to
explain how it works.
1.1

 Nylon
 In the early 1930’s,
Wallace Carothers
produced nylon while
researching cotton and
silk.
 A team of scientists and
engineers applied
Carothers’s research to
the commercial
production of nylon.
1.1

 Aspirin
▪ Long before researchers figured out how aspirin
works, people used it to relieve pain, and
doctors prescribed it for patients who were at
risk for a heart attack.
▪ In 1971, it was discovered that aspirin can block
the production of a group of chemicals that
cause pain and lead to the formation of blood
clots. This is an example of pure research.
1.1

Technology is the means by which a
society provides its members with those
things needed and desired.
▪Technology allows humans to do
some things more quickly or with less
effort.
▪There are debates about the risks and
benefits of technology.
1.1

Why Study Chemistry?
What are three general reasons
to study chemistry?
1.1

Chemistry can be useful in
explaining the natural world,
preparing people for career
opportunities, and producing
informed citizens.
1.1

 Explaining the Natural World
Chemistry can help you satisfy
your natural desire to understand
how things work.
1.1

 Preparing For a Career
 Many careers require knowledge of chemistry. A
photographer uses chemical processes to control
the development of photographs in a darkroom.
1.1

Being an Informed Citizen
 Knowledge of chemistry
and other sciences can
help you evaluate the
data presented, arrive at
an informed opinion, and
take appropriate action.
1.1

Materials
What impact do chemists have on
materials, energy, medicine,
agriculture, the environment, and
the study of the universe?
1.2

Chemists design
materials to fit specific
needs.
1.2

 In 1948, George de Mestral took
a close look at the burrs that
stuck to his clothing. He saw
that each burr was covered with
many tiny hooks.
 In 1955, de Mestral patented
the design for the hook-and-
loop tapes. These are used as
fasteners in shoes and gloves.
1.2

This story illustrates two ways of looking
at the world—the macroscopic view and
the microscopic view.
 Burrs belong to the macroscopic world, the
world of objects that are large enough to
see with the unaided eye.
 The hooks belong to the microscopic
world, or the world of objects that can be
seen only under magnification.
1.2

Energy
Chemists play an essential
role in finding ways to
conserve energy, produce
energy, and store energy.
1.2

 Conservation
 One of the easiest ways to conserve
energy is through insulation. Insulation
acts as a barrier to heat flow from the
inside to the outside of a house or from
the outside to the inside of a freezer.
1.2

▪ SEAgel is a modern insulation that is light
enough to float on soap bubbles.
1.2

 Production
▪ The burning of coal, petroleum, and natural gas
is a major source of energy. These materials are
called fossil fuels. Oil from the soybeans is used
to make biodiesel.
1.2

 Storage
▪ Batteries are devices that use chemicals
to store energy that will be released as
electric current.
▪ For some applications, it important to
have batteries that can be recharged
rather than thrown away. Digital cameras,
wireless phones, and laptop computers
use rechargeable batteries.
1.2

 Medicine and Biotechnology
Chemistry supplies the
medicines, materials, and
technology that doctors
use to treat their patients.
1.2

 Medicines
 There are over 2000 prescription
drugs. Many drugs are effective
because they interact in a specific way
with chemicals in cells. Knowledge of
the structure and function of these
target chemicals helps a chemist
design safe and effective drugs.
1.2

 Materials
 Chemistry can supply materials to
repair or replace body parts. Artificial
hips and knees made from metals and
plastics can replace worn-out joints
and allow people to walk again without
pain.
1.2

 Biotechnology
 From 1990 to 2003, scientists
worldwide worked on the
Human Genome Project.
They identified the genes
that comprise human DNA—
about 30,000. The discovery
of the structure of DNA led to
the development of
biotechnology.
1.2

Biotechnology applies science to the
production of biological products or
processes.
1.2

Agriculture
Chemists help to develop more
productive crops and safer, more
effective ways to protect crops.
1.2

 Productivity
 One way to track productivity is to
measure the amount of edible food
that is grown on a given unit of land.
 Chemists test soil to see if it contains
the right chemicals to grow a particular
crop and recommend ways to improve
the soil.
1.2

 Chemists also help
determine when a
crop needs water.
 If the genes from a
jellyfish that glows
are transferred to a
potato plant, the
plant glows when it
needs to be watered.
1.2

 Crop Protection
 Chemists sometimes use chemicals produced by
insects to fight insect pests. The plastic tube
wrapped around the stem of the tomato plant
contains a chemical that a female pinworm moth
emits to attract male moths. It interferes with the
mating process so that fewer pinworms are
produced.
1.2

 The Environment
▪A pollutant is a material found in
air, water, or soil that is harmful
to humans or other organisms.
▪Chemists help to identify
pollutants and prevent pollution.
1.2

 Identify Pollutants
 Until the mid-1900s, lead was used in many
products, including paints and gasoline.
 A study done in 1971 showed that the level of
lead that is harmful to humans is much lower
than had been thought, especially for
children. Even low levels of lead in the blood
can permanently damage the nervous
system of a growing child.
1.2

 Prevent Pollution
 The strategies used to
prevent lead poisoning
include testing
children’s blood for
lead, regulation of
home sales to families
with young children,
and public awareness
campaigns with
posters.
1.2

 The percentage of children with elevated
blood levels has decreased since the 1970s.
1.2

The Universe
To study the universe, chemists
gather data from afar and analyze
matter that is brought back to
Earth.
1.2

 Chemists have analyzed more than 850
pounds of moon rocks that were brought
back to Earth. Some of these rocks are similar
to rocks formed by volcanoes on Earth,
suggesting that vast oceans of molten lava
once covered the moon's surface.
1.2

▪ The robotic vehicle Opportunity was designed to
determine the chemical composition of rocks and soil on
Mars. Data collected at the vehicle’s landing site
indicated that the site was once drenched with water.
1.2

 In 1928, Alexander Fleming
noticed that bacteria he was
studying did not grow in the
presence of a yellow-green
mold. In 1945, Fleming shared a
Nobel Prize for Medicine with
Howard Florey and Ernst Chain,
who led the team that isolated
penicillin.
1.3

Alchemy
 How did alchemy lay the groundwork
for chemistry?
1.3

 Alchemists developed the tools and
techniques for working with chemicals.
1.3

 Alchemists developed
processes for separating
mixtures and purifying
chemicals. They
designed equipment that
is still in use today
including beakers, flasks,
tongs, funnels, and the
mortar and pestle. Mortar and Pestle
1.3

An Experimental
Approach to Science
How did Lavoisier help to
transform chemistry?
1.3

Lavoisier helped to transform
chemistry from a science of
observation to the science of
measurement that it is today.
1.3

 Lavoisier designed a balance that could measure
mass to the nearest 0.0005 gram. He also showed
that oxygen is required for a material to burn.
Reconstruction of Lavoisier’s Laboratory
1.3

The Scientific Method
What are the steps in the
scientific method?
1.3

▪ The scientific method is a logical,
systematic approach to the solution of a
scientific problem.
▪ Steps in the scientific method include making
observations, testing hypotheses, and
developing theories.
1.3

 Making Observations
 When you use your senses
to obtain information, you
make an observation.
 Suppose you try to turn on
a flashlight and it does not
light. An observation can
lead to a question: What’s
wrong with the flashlight?
1.3

 Testing Hypotheses
 A hypothesis is a proposed explanation for
an observation.
 You guess that the flashlight needs new
batteries. You can test your hypothesis by
putting new batteries in the flashlight. If the
flashlight lights, you can be fairly certain
that your hypothesis is true.
1.3

 An experiment is 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.
1.3

Developing Theories
▪ Once a hypothesis meets the test of
repeated experimentation, it may become
a theory.
▪ A theory is a well-tested explanation for a
broad set of observations.
▪ A theory may need to be changed at some
point in the future to explain new observations
or experimental results.
1.3

 Scientific Laws
 A scientific law is a concise statement
that summarizes the results of many
observations and experiments.
 A scientific law doesn’t try to explain
the relationship it describes. That
explanation requires a theory.
1.3

Steps in the Scientific Method
1.3

Collaboration and Communication
 What role do collaboration and
communication play in science?
1.3

No matter how talented the players on a
team, one player cannot ensure victory
for the team. Individuals must
collaborate, or work together, for the
good of the team.
 When scientists collaborate and
communicate, they increase the likelihood
of a successful outcome.
1.3

 Collaboration
 Scientists choose to collaborate for
different reasons.
▪ Some research problems are so complex
that no one person could have all of the
knowledge, skills, and resources to solve the
problem.
▪ Scientists might conduct research for an
industry in exchange for equipment and the
time to do the research.
1.3

 Collaboration isn’t always a smooth process.
You will likely work on a team in the
laboratory. If so, you may face some
challenges. But you can also experience the
benefits of collaboration.
1.3

 Communication
 Scientists communicate
face to face, by e-mail, by
phone, and at international
conferences.
 Scientists publish their
results in scientific journals.
Articles are published only
after being reviewed by
experts in the author’s field.
1.3

 Shape-sorter toys
fascinate young
children. Typically, the
children try placing a
shape in different holes
until they find the right
one. The trial-and-error
approach is one method
of problem solving, but
it is usually not the best
one.
1.4

 Skills Used in Solving Problems
 What is a general approach to solving a problem?
1.4

▪Effective problem solving
always involves developing a
plan and then implementing
that plan.
1.4

Shopping involves problem solving skills.
1.4

 Solving Numeric Problems
 What are the three steps for solving numeric
problems?
1.4

 The steps for solving a numeric word problem
are analyze, calculate, and evaluate.
1.4

 Analyze
 To solve a word problem, you must first
determine where you are starting from
(identify what is known) and where you
are going (identify the unknown).
 After you identify the known and the
unknown, you need to make a plan for
getting from the known to the
unknown.
1.4

 Calculate
 If you make an effective plan, doing the
calculations is usually the easiest part of the
process.
 Evaluate
 Check that your answer is reasonable and
makes sense. Check that it has the correct
unit and the correct number of significant
figures.
1.4

Figure 1.25 Map of Indianapolis

Solving Conceptual Problems
What are the two steps for solving
conceptual problems?
1.4

 The steps for solving a conceptual problem
are analyze and solve.
1.4

Problem Solving 1.29 Solve Problem 29
with the help of an interactive guided
tutorial.

 Bamboo has properties
that make it a good choice
for use in chopsticks. It has
no noticeable odor or
taste. It is hard, yet easy to
split, and it is heat
resistant. You will learn
how properties can be
used to classify and
identify matter.
2.1

Describing Matter
How can properties used to
describe matter be classified?
2.1

Properties used to describe
matter can be classified as
extensive or intensive.
2.1

Extensive Properties
 The mass of an object is a measure of the
amount of matter the object contains.
 The volume of an object is a measure of the
space occupied by the object.
 An extensive property is a property that
depends on the amount of matter in a
sample.
2.1

Intensive Properties
▪ An intensive property is a
property that depends on
the type of matter in a
sample, not the amount of
matter. The hardness of a
bowling ball is an example
of an intensive property.
2.1

Identifying Substances
Why do all samples of a substance
have the same intensive
properties?
2.1

 Matter that has a uniform and definite
composition is called a substance. These
kettles are mainly copper. Copper is an
example of a substance.
2.1

▪ This sculpture of a falcon is
made of gold. Gold is an
example of a substance.
2.1

 Every sample of a given substance has
identical intensive properties because every
sample has the same composition.
▪
2.1

▪A physical property is a quality or
condition of a substance that can be
observed or measured without
changing the substance’s
composition.
▪Hardness, color, conductivity, and
malleability are examples of physical
properties.
2.1

States of Matter
What are three states of matter?
2.1

Three states of matter are solid,
liquid, and gas.
2.1

Solids
▪A solid is a form
of matter that has
a definite shape
and volume.
2.1

 Liquid
▪ A liquid is a form of
matter that has an
indefinite shape,
flows, yet has a fixed
volume.
2.1

Gases
▪A gas is a form of
matter that takes
both the shape and
volume of its
container.
2.1

▪Vapor describes the gaseous
state of a substance that is
generally a liquid or solid at
room temperature, as in
water vapor.
2.1

Physical Changes
How can physical
changes be classified?
2.1

 During a physical change,
some properties of a material
change, but the composition
of the material does not
change.
 As gallium melts in a person’s
hand, the shape of the
sample changes, but the
composition of the material
does not change.
2.1

 Physical changes can be classified as
reversible or irreversible.
▪ All physical changes that involve a
change from one state to another are
reversible.
▪ Cutting hair, filing nails, and cracking an
egg are examples of irreversible physical
changes.
2.1

 Panning is one way to separate
gold from a mixture of gold and
materials such as sand or gravel.
A pan containing the mixture is
place underwater and shaken
vigorously from left to right. You
will learn how to classify and
separate mixtures.
2.2

Classifying Mixtures
How can mixtures be classified?
2.2

▪ A mixture is a physical blend of two or more
components.
▪ A salad bar provides a range of items. Customers
choose how much of each item to use in their salads.
Each salad has a different composition.
2.2

 Based on the distribution of their
components, mixtures can be classified
as heterogeneous mixtures or as
homogeneous mixtures.
2.2

Heterogeneous Mixtures
▪A mixture in which the composition
is not uniform throughout is a
heterogeneous mixture.
2.2

Homogeneous Mixtures
▪A mixture in which the composition is
uniform throughout is a homogeneous
mixture.
▪Another name for a homogeneous
mixture is a solution.
2.2

2.2
▪The term phase is used to
describe any part of a sample
with uniform composition and
properties.
▪A homogenous mixture consists
of a single phase.
▪A heterogeneous mixture consists
of two or more phases.

2.2
▪When oil and vinegar are
mixed they form layers,
or phases. The oil phase
floats on the water
phase.

2.2
Separating Mixtures
 How can mixtures be separated?

Differences in physical properties
can be used to separate mixtures.
2.2

 Filtration
▪ The process that separates a solid from the liquid in a
heterogeneous mixture is called filtration.
▪ A colander is used to separate pasta from the water in
which it was cooked. This process is a type of filtration.
2.2

 Distillation
▪ During a distillation, a liquid is boiled to produce a vapor
that is then condensed into a liquid.
2.2

 Take two pounds of sugar, two
cups of boiling water, and one
quarter teaspoon of cream of
tartar. Add food coloring and you
have the sticky, sweet concoction
known as cotton candy. You will
learn how substances are classified
as elements or compounds.
2.3

Distinguishing Elements
and Compounds
 How are elements and
compounds different?

An element is the simplest form of
matter that has a unique set of
properties.
A compound is a substance that
contains two or more elements
chemically combined in a fixed
proportion.

 Compounds can be broken down into simpler
substances by chemical means, but elements
cannot.

Breaking Down Compounds
 A chemical change is a
change that produces matter
with a different composition
than the original matter.
 When table sugar is heated, it
goes through a series of
chemical changes.

▪ The final products of these chemical changes are solid
carbon and water vapor. The following diagram
summarizes the process.


 Properties of Compounds
▪In general, the properties of compounds
are quite different from those of their
component elements.
▪When the elements sodium and chlorine
combine chemically to form sodium
chloride, there is a change in composition
and a change in properties.

Chlorine is
used to kill
harmful
organisms in
swimming
pools.

 Sodium is stored
under oil to keep it
from reacting with
oxygen or water
vapor in the air.
Sodium vapor
produces the light
in some street
lamps.

Sodium Chloride
(commonly
known as table
salt) is used to
season or
preserve food.

Distinguishing Substances and Mixtures
How can substances and
mixtures be distinguished?

If the composition of a
material is fixed, the
material is a substance. If
the composition of a
material may vary, the
material is a mixture.

▪ This flowchart
summarizes
the process
for classifying
matter.


 Iron is abundant, easy to shape
when heated, and relatively
strong, especially when mixed
with carbon in steel. Over time,
objects made of iron will rust if
they are left exposed to air.
You will learn to recognize
chemical changes and to
distinguish them from physical
changes.

Chemical Changes
 What always happens
during a chemical change?

 The ability of a substance to undergo a
specific chemical change is called a chemical
property.
 Chemical properties can be used to identify a
substance. But chemical properties can be
observed only when a substance undergoes a
chemical change.

During a chemical change, the
composition of matter always changes.
Recall that during a physical change, the
composition of matter never changes.

▪ A magnet separates iron from sulfur. This is an example
of a physical change.

▪ A mixture of iron and sulfur is heated. The iron and sulfur
react and form iron sulfide. This is an example of a
chemical change.

 A chemical change is also called a chemical
reaction.
 One or more substances change into one or
more new substances during a chemical
reaction.
 A substance present at the start of the
reaction is a reactant.
 A substance produced in the reaction is a
product.

Recognizing Chemical Changes
What are four possible clues that a
chemical change has taken place?

Possible clues to chemical change
include:
 a transfer of energy
 a change in color
 the production of a gas
 the formation of a precipitate.

▪ A precipitate is a solid that forms and settles out of a
liquid mixture.
▪ Clues to chemical changes have practical applications.

Conservation of Mass
How are the mass of the
reactants and the mass of
the products of a chemical
reaction related?

During any chemical
reaction, the mass of the
products is always equal to
the mass of the reactants.

 The law of conservation of mass states that in any
physical change or chemical reaction, mass is
conserved.
 The conservation of mass is easily observed when a
change occurs in a closed container.

Chemistry Unit 1 PPT 1

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