Introduction to Chemistry

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Introduction to Chemistry

• Chapter 1

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Chemistry and Matter

• Chemistry is the study of matter and the changes
  that it undergoes.

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Matter and its Characteristics

• Matter anything that has mass and takes up
  space.

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Matter and its Characteristics

• Mass and Weight
• Mass the amount of matter that makes up an
  object.
• Weight the amount of matter in an object AND
  the effect of Earths gravitational pull on that
  matter.
• The mass of an object DOES NOT change with
  location
• The weight of an object DOES change if the force
  of gravity changes. (Things weigh less on the
  moon because the moons gravity is lower than
  earths.)

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Scientific Method

• The Scientific Method is an organized plan used
  to gather, organize and share information.

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Scientific Method
Make an Observation (Ask a Question) Uses the
senses (sight, hearing, taste, touch, smell)
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Scientific Method

• Develop a Hypothesis
• A Prediction
• An educated guess
• Developed in an attempt to answer a question.
• Must be testable.

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Scientific Method

• Test the Hypothesis
• Perform an Experiment, gather data.
• Qualitative Data information that describes
  color, odor, shape, or some other physical
  characteristic.
• Quantitative Data numerical information telling
  how much, how little, how fast, etc.

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Scientific Method
Analyze Data
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Scientific Method
Draw Conclusions
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Scientific Method
If the data does not support the hypothesis,
revise (change) the hypothesis.
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Scientific Method
Develop a Theory
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Scientific Method

• Theory
• Developed after MANY, MANY experiments have
  supported the hypothesis
• Explains the question or observation.

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Scientific Method
Whats the difference between a Scientific
Theory and a Scientific Law?
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Scientific Method
Theory Explains the question or observation
weve made.
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Scientific Method

• Scientific Law
• Summarizes a pattern found in nature
• Does NOT explain the observation or question.

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Experimentation
Controlled Experiment In a controlled
experiment, there are two groups
Control Group a group or material that all
conditions (except the independent variable) are
identical to the experimental group.
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Experimentation
Controlled Experiment In a controlled
experiment, there are two groups
Experimental Group the group or material
with which you are deliberately changing the
independent variable.
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Experimentation
In an experiment, there are two variables

• Independent Variable the condition that is
  controlled (and changed) by the scientist
  Manipulated Variable. Graphed on the X-Axis of a
  graph.
• Dependent Variable the result of the change in
  the independent variable. Graphed on the Y-Axis
  of a graph.
• Remember In a controlled experiment, Only ONE
  independent variable is changed at a time.

• Independent Variable

• Dependent Variable

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Types of Research

• Pure Research Research that seeks only to gain
  knowledge.

• Applied Research Research that seeks to solve a
  problem.

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Technology

• Technology is the practical use of scientific
  information. It is used to make improvements in
  human life and the world around us.

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Data Analysis

• Chapter 2

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Units of Measurement

• Scientists are able to communicate
  internationally because they all use the same
  units the International System of Units (SI).

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Metric (SI) Prefixes
After you learn the base units, you need to
understand the prefixes.
Example 1 kilogram means 1000 grams.
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Volume

• Volume is how much space an object takes up.
• The metric unit for volume we normally use in
  chemistry is the Liter. A liter is approximately
  equal to one quart.
• 1 L 1 dm3
• 1 ml 1 cm3

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Density

• Density is mass divided by volume.

Units g/cm3

• Density of water is 1 g/cm3

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Density Lab
Required Materials
Triple-beam balance Graduated Cylinder cm
Ruler water Objects to be measured
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Temperature

• In science we use two Temperature Scales

• Celsius Scale uses the freezing point and
  boiling point of water.
• Freezing point of water 0C
• Boiling point of water 100C

• Kelvin Scale uses absolute zero
• K C 273
• Freezing point of water 273 K
• Boiling point of water 373 K

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Scientific Notation
In science, we sometimes use very large or very
small numbers. These numbers are hard to write
so
We use Scientific Notation to make writing these
numbers easier.
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Scientific Notation

• Multiplying Exponents
• (1 x 103) x (2 x 104)

You multiply the first numbers (1 x 2)
and add the exponents (3 4).
(1 x 2) x 10(34)
2 x 107
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Scientific Notation

• Dividing Exponents
• (1 x 103) (2 x 104) first, lets rewrite it

1 x 103
2 x 104
You divide the first numbers (1/2) and subtract
the exponents (3 - 4).
1 X 10 (3-4)
2 X 10 (3-4)
.5 x 10-1
5 x 10-2
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Significant Figures

• The precision of the instruments used determines
  how exact your data is and determines the number
  of significant figures in your calculations.
• Significant figures include all known digits plus
  one estimated digit.

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Significant Figures

• Rules for Significant Figures
• Non-Zero numbers are always significant.
  72.3 g has 3
• Zeros between non-zero numbers are significant.
  60.5 g has 3
• All final zeros to the right of the decimal place
  6.20 g has 3are significant.
• Zeros that are placeholders are NOT significant.
  0.0253 has 3
  4320
  has 3

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Tables and Graphs

• Data is also presented in graphs.

Types of graphs Bar graphs Line graphs Circle
graphs
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Tables and Graphs

• Bar Graphs are often used to compare sets of data.

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Tables and Graphs

• Circle Graphs are often used to show how one part
  compares to the whole.

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Tables and Graphs

• Line Graphs are often used to show how one
  variable changes in response to another.

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Tables and Graphs

• The slope on line graphs can also give us
  information.

The slope of a line is rise over run.
Slope 3 g/ml
The slope of this line tells us density!
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Tables and Graphs

• Graphs need to have the following labels
• Dependent Variable on Y-Axis
• Y-Axis Title
• Y-Axis Units
• Independent Variable on X-Axis
• X-Axis Title
• X-Axis Units
• Graph Title
• Reasonable graph

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Matter Properties and Changes

• Chapter 3

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Properties of Matter

• Substance (also known as a Pure Substance)
  matter that has a uniform and unchanging
  composition.
• Water is a substance H2O each atom of water is
  always made up of two Hydrogen atoms and one
  Oxygen atom.
• Seawater is NOT a substance samples taken at
  different locations will have different
  compositions.

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Properties of Matter

• Physical Property can be tested without
  changing the composition of the substance.
• Water can be frozen but it is still H2O.
• Ice can be melted but it is still H2O.
• Water can be boiled to form vapor but it is
  still H2O.

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Properties of Matter

• Chemical Property the way a substance combines
  with (reacts with) another substance to form a
  new substance.
• Sodium an unstable metallic element reacts with
  Chlorine an unstable gaseous element to form
  Sodium Chloride Table Salt.2 Na Cl2 ? 2 NaCl
• Iron reacts with Oxygen to form rust.4 Fe 3 O2
  ? 2 Fe2O3

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Properties of Matter

• States of Matter

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Properties of Matter

• States of Matter
• Solid
• Liquid
• Gas

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Properties of Matter
Solid

• Has a definite shape and volume
• Atoms are packed closely together and have an
  orderly arrangement of atoms

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Properties of Matter
Solid

• Solids have a definite volume and shape because
  the particles of a solid vibrate around fixed
  locations.

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Properties of Matter
Solid

• Solids are only very slightly compressible.

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Properties of Matter
Liquid

• Has a definite volume, but not a definite shape
• Atoms are close together but the arrangement of
  atoms is more random

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Properties of Matter
Liquid

• Takes on the shape of its container because
  particles can flow to new locations
• The volume is constant because forces of
  attraction keep the particles close together.

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Properties of Matter
Liquid

• Liquids are slightly compressible.

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Properties of Matter
Gas

• Has no definite shape nor definite volume
• Atoms are loosely spaced and are not arranged in
  a regular pattern

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Properties of Matter
Gas

• The constant motion of particles in a gas allows
  a gas to fill a container of any shape or size.

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Properties of Matter
Gas

• Gases are highly compressible.

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Properties of Matter
States of Matter

• Solid
• Liquid
• Gas

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Properties of Matter
Phase Changes
When enough kinetic energy is added to a solid,
it can become a liquid.
When enough kinetic energy is added to a liquid,
it can become a gas.
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Properties of Matter
Phase Changes
Melting, freezing, vaporization, condensation,
sublimation and deposition are six common phase
changes.
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Properties of Matter
Freezing

• Often, farmers spray water (that freezes) onto
  tender blossoms and fruit to protect them from
  freeze damage.

When water freezes, temperature decreases so
the water is giving up energy.

• So, freezing is an exothermic change (releases
  heat)!

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Properties of Matter
Phase Changes
Liquid Gas
Boiling Point
Liquid
Solid / Solid Liquid
Melting Point
Note Temperature does not change during a phase
change.
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Properties of Matter

• Endothermic - describes a process or reaction
  that absorbs energy in the form of heat
  Sublimation, melting and vaporization are
  endothermic processes (heat is absorbed).
• Exothermic - describes a process or reaction that
  releases heat Deposition, freezing and
  condensation are exothermic processes (heat is
  released).

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Properties of Matter
Chemical Changes

• Chemical Changes are usually referred to as a
  chemical reaction.

• Law of Conservation of Mass states that mass is
  neither created nor destroyed during a chemical
  reaction.
• So, the mass of the reactants must equal the mass
  of the products.

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Properties of Matter
Mixtures

• A Mixture is a combination of two or more pure
  substances where each substance keeps its
  individual chemical properties.
• Heterogeneous Mixture is not blended smoothly
  individual substances remain distinct. Examples
  Sand, Tossed Salad.
• Homogeneous Mixture SOLUTION there is a
  constant composition throughout. Examples Sugar
  water, Air, Alloy (solution of metals).

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Properties of Matter
Mixtures Separation Techniques

• Remember A Mixture is a combination of two or
  more pure substances where each substance keeps
  its individual chemical properties. So, we should
  be able to separate them!

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Properties of Matter
Mixtures Separation Techniques

• Methods for Separation
• Filtration
• Distillation
• Crystallization
• Chromatography

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Properties of Matter
Mixtures Separation Techniques

• Filtration a method to separate liquids from
  solids.

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Properties of Matter
Mixtures Separation Techniques

• Crystallization a method to recover substances
  in a solution.

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Properties of Matter
Mixtures Separation Techniques

• Distillation a method to separate mixtures
  based on boiling points.

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Properties of Matter
Mixtures Separation Techniques

• Chromatography a method that separates a
  mixture by its tendency to move across a surface
  of another material.

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Properties of Matter
Mixtures Separation Techniques
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Properties of Matter
Elements and Compounds
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Properties of Matter
Elements and Compounds
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Properties of Matter
Elements and Compounds
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Properties of Matter
Elements and Compounds
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Properties of Matter
Elements and Compounds
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Properties of Matter
Elements and Compounds
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Properties of Matter
Elements and Compounds
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Properties of Matter
Elements and Compounds
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Elements and Compounds

• Element a pure substance that cannot be
  separated into simpler sub stances by physical or
  chemical means.
• Compound a combination of two or more different
  elements that are combined chemically.
• The properties of a compound are different from
  the properties of the elements it is made of.

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Elements and Compounds

• Compounds can be broken down into simpler
  substances by chemical means.Example Water can
  be broken down into Hydrogen and Oxygen2 H2O ?
  2 H2 O2

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Law of Definite Proportions
Elements and Compounds

• This law states that regardless of amount, a
  compound is always composed of the same elements
  in the same proportion by mass.

• When water is broken down, two parts of hydrogen
  and one part of oxygen are always produced. Also,
  the ratio of weight of Oxygen to Hydrogen is
  always 8 1.

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Law of Multiple Proportions
Elements and Compounds

• This law states that the same elements can
  combine in different ratios to form different
  compounds.

• Shown here are two compounds containing Copper
  and Chlorine. Compound 1 is CuCl. Compound 2 is
  CuCl2.

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Phase Diagrams
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Phase Diagrams
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Phase Diagrams
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SolubilityCurve