Ch. 1--What Is Chemistry?

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Ch. 1--What Is Chemistry?

• 1.1Chemistry is a Physical Science
• 1.2Matter and Its Properties
• 1.3Elements

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1.1- Chemistry is a physical science

• Chemistry is the study of the composition of
  matter and the changes that matter undergoes.
• Matter is anything that has mass and occupies
  space.
• Why is the scope of chemistry so vast?
• Because living and nonliving things are made
  of matter, chemistry affects all aspects of life
  and most natural events.

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Areas of Study
1.1

• There are many areas of study in chemistry.
  Some topics have specific names while others are
  generalizations.
• We will specifically cover organic and nuclear
  chemistry
• Most everything we talk about outside of the
  organic chapter is considered inorganic chemistry
• When we look at the components and composition of
  materials it is considered analytical chemistry
• Thermochemistry is a large part of the broad
  category of physical chemistry

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Why Study Chemistry?
1.1

Chemistry can help you satisfy your natural
desire to understand how things work. Chemistry
can be useful in explaining the natural world,
preparing people for career opportunities, and
producing informed citizens. Pure research can
lead directly to an application, but an
application can exist before research is done to
explain how it works.
Pure chemistry is the pursuit of chemical
knowledge for its own sake (basic
research). Applied chemistry is research that is
directed toward a practical goal or application
(applied research).
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Pure and Applied Chemistry
1.1

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

• 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. (ex. Hippocrates (400
  B.C.) left historical records of pain relief
  treatments, including the use of powder made from
  the bark and leaves of the willow tree to help
  heal headaches, pains and fevers.)
• 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.

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Pure and Applied Chemistry
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.

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Alchemy before Chemistry
1.3

• Early chemistry is called alchemy. Alchemists
  developed the tools and techniques for working
  with chemicals. Chemistry is a systematic method
  of study of matter.

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.
Antoine-Laurent Lavoisier (late 1700s) Lavoisier
helped to transform chemistry from a science of
observation to the science of measurement that it
is today. He 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.
Mortar and Pestle
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1.2- Matter and its properties

• Mass is a measure of the amount of matter
• Basic Building Block of Matter
• The fundamental building blocks of matter are
  atoms and molecules.
• An atom is the smallest unit of matter that has
  the properties of that matter.
• An element is a pure substance made of only one
  kind of atom. Ex. hydrogen, oxygen.
• A compound is a substance that is made from the
  atoms of two or more elements that are
  chemically bonded.

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Properties of Matter

• Properties can help reveal the identity of an
  unknown substance. Usually one needs to determine
  more than one property of the substance to
  identify it.. There are two types of properties
  extensive and intensive.
• Extensive properties depend on the amount of
  matter present such as mass or volume.
• Intensive properties are independent of the
  amount of substance such as melting point,
  boiling point, or density.

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States of Matter
2.1
Three states of matter are solid, liquid, and
gas.
A solid is a form of matter that has a definite
shape and volume.
A liquid is a form of matter that has an
indefinite shape, flows, yet has a fixed volume.
A gas is a form of matter that takes both the
shape and volume of its container.
Vapor describes the gaseous state of a substance
that is generally a liquid or solid at room
temperature, as in water vapor.
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Matter exists in three states.

• Solid A solid is rigid and has
• fixed volume and shape.
• Ex. ice, book, pencil, etc.
• Liquid  A liquid has a definite
• volume but no definite shape.
• It takes the shape of its container.
• Ex. water, oil, wine, etc.
• Gas A gas has no definite
• volume or shape. It takes on the
• shape and volume of its container.
• Ex. steam, air, hydrogen, etc.

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physical and chemical properties

• Physical Property
• The physical properties of matter include what we
  see when we look at an object such as the color
  or state of the object (solid, liquid, gas). A
  physical property is a characteristic that can be
  observed without changing the identity of the
  substance.
• A change in the substance that does not involve
  the change in the identity of the substance is
  called a physical change. Common physical changes
  are the changes of state (such as water freezing
  from liquid to solid, or boiling where the water
  changes from liquid to gas state), hardness,
  color, conductivity, and malleability.
•  
•  

As gallium melts in a persons hand, the shape of
the sample changes, but the composition of the
material does not change.
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physical and chemical properties

• Chemical Property
• The chemical properties of matter are what we see
  or what we get when matter interacts with other
  matter, such as when we mix 2 liquids. We can
  only observe chemical properties, or changes in
  chemical properties by interacting substances
  with each other. The chemical property is a
  substances ability to undergo changes that will
  transform it into a new substance. A change in
  which one or substances are converted into
  different substances is called a chemical change.
  The chemical changes are generally referred to as
  chemical reactions in which the beginning
  substances are called reactants and the ending
  substances are called products.
•  
• Ex. of chemical reactions are rusting of iron,
  burning of wood, etc.

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Chemical Changes
2.4

• 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.
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Recognizing Chemical Changes
2.4

• Possible clues to chemical change include
• a. a transfer of energyb. a change in colorc.
  the production of a gasd. the formation of a
  precipitate

c cheese (milk curds and liquid whey)
A precipitate is a solid that forms and settles
out of a liquid mixture. Clues to chemical
changes have practical applications.
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Classifying Mixtures
2.2

• A mixture has a variable composition.
• Ex. wood, wine, air. Mixtures can be of two
  types
•  
• A pure substance will always have the same
• composition. Pure substances are either
• elements or compounds.
• Elements Elements are substances that
• cannot decomposed into simpler substances
• by chemical or physical means. Ex. carbon,
  oxygen.
• Compounds A compound can be broken down into
  elements by chemical means. Ex. water, ozone,
  carbon dioxide.
•  
• When physical or chemical changes occur, energy
  is almost always involved. The energy can take
  several different forms such as heat or light.
  Energy can be absorbed or released

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Classifying Mixtures
2.2

• Based on the distribution of their components,
  mixtures can be classified as heterogeneous
  mixtures or as homogeneous mixtures.
• A mixture in which the composition is not
  uniform throughout is a heterogeneous mixture.
• A mixture in which the composition is uniform
  throughout is a homogeneous mixture.
• Another name for a homogeneous mixture is a
  solution.

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Classifying Mixtures
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.

When oil and vinegar are mixed they form layers,
or phases. The oil phase floats on the water
phase.
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Separation of Mixtures (Physical Methods of
Separation)

• All mixtures can be separated by exploiting some
  physical property. No chemical changes need to be
  involved, so the substances retain their chemical
  identity through the separation process.
  Chemists use various processes for separating
  different kinds of mixtures such as hand
  separation, filtration, using a separating
  funnel, distillation, centrifugation, or
  chromatography.
•  

During a distillation, a liquid is boiled to
produce a vapor that is then condensed into a
liquid.
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.
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Separation of Compounds (Chemical Separation)

• Chemical separation is used to break down a
  compound in its elements. Chemical means of
  separation are pretty harsh. One commonly
  employed method for chemical separation is
  electrolysis.

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Distinguishing Substances and Mixtures
2.3
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. Sodium chloride (table salt) is one atom
of sodium for every one atom of chlorine
(chloride) and, therefore, a substance
(compound). Steel, however, is an alloy often
made primarily of carbon and iron. There may be
a different amount of iron atoms per carbon atom
depending on the purpose of the steel and is,
therefore, a mixture.
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Distinguishing Substances and Mixtures
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Conservation of Mass and Energy
2.4

• The law of conservation of mass states that in
  any physical change or chemical reaction, mass is
  conserved.
• During any chemical reaction, the mass of the
  products is always equal to the mass of the
  reactants.
• The conservation of mass is easily observed when
  a change occurs in a closed container.

The law of conservation of energy states that in
a physical or chemical reaction, energy is
conserved. Energy may be released or absorbed in
a reaction, but the amount of energy in the
entire system (ex. Universe) remains the same.
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1.3- Elements

• Periodic Table of Elements
• Each small square in the periodic table contains
  one element. The horizontal rows are called as
  the periods. The vertical columns are called as
  groups, or families.

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1.3- Elements
4.3

• A periodic table is an arrangement of elements in
  which the elements are separated into groups
  based on a set of repeating properties.
• A periodic table allows you to easily compare the
  properties of one element (or a group of
  elements) to another element (or group of
  elements).
• Each horizontal row of the periodic table is
  called a period. Within a given period, the
  properties of the elements vary as you move
  across it from element to element.
• Each vertical column of the periodic table is
  called a group, or family. Elements within a
  group have similar chemical and physical
  properties.

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Metals, Nonmetals, and Metalloids
6.1

• Metals, Metalloids, and Nonmetals in the Periodic
  Table