Chapter 1 Chemistry: The Science of Matter

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Chapter 1 Chemistry The Science of Matter

• Section 1.1 The Puzzle of Matter
• Section 1.2 Properties and Changes of Matter

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Section 1.1 Objectives

• Classify matter according to its composition.
• Distinguish among elements, compounds,
  homogeneous mixtures, and heterogeneous mixtures.
• Relate the properties of matter to its structure.

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Composition, Structure and Behavior

• Chemistry- the science that investigates and
  explains the structure and properties of matter.
• Matter- anything that takes up space and has mass
• Mass- the measure of the amount of matter that
  an object contains

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Matter

• Matter is all around you.
• Phone
• Your neighbor
• The desk
• The metal of your chair
• The air you are breathing
• What isnt matter
• Heat
• Light
• Thoughts
• Ideas
• Radio waves
• Magnetic fields

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Mass

• On earth we equate mass with weight.
• A bowling ball has a larger mass than a tennis
  ball.
• I have more mass than the text book.

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Matter

• The structure of matter refers to its
  composition-what is it made of and how is it
  organized
• The properties of matter describe the
  characteristics and behavior of matter.
• Changes matter undergoes

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Comparing Composition and Behavior (Figure 1.2
page 5)

• Salt and Water
• Salt is Na and Cl
• Water is H and O
• You can wash you hair in water, but not in salt.
  And you sprinkle water over popcorn.
• Aspirin and Sucrose
• Both are composed of C, H, and O
• You wouldnt use aspirin to sweeten cereal or use
  sucrose for a headache

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Properties

• You can determine some of the properties of a
  particular chunk of matter by examination and
  manipulation.
• What is its color?
• Is it a solid, liquid or gas?
• Is it soft or hard?
• Does it dissolve in water?

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Properties of Iron

• Strong, but can be flattened and stretched
• Does not dissolve in water
• Turns to a liquid at high temperatures
• Is a gray, shiny solid
• Is attracted to a magnet
• Conduct electricity

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Properties and Composition

• You may be able to determine many properties of a
  piece of matter by examining it and doing some
  simple tests.
• However, you can not determine what it is
  composed of just by looking at it.

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Examining Matter The Macroscopic View of Matter

• The macroscopic view of matter is one in which
  you touch, smell, taste and see.

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The Submicroscopic View of Matter

• Gives you a glimpse into the world of atoms
• You cannot see this world even with the most
  powerful microscopic.
• Matter is made up of atoms
• Atoms are so small that a period at the end of a
  sentence is made up of 100,000,000,000,000,000,000
  (100 quintillion) carbon atoms.
• If you could count all 100 quintillion atoms at a
  rate of three per second it would take you a
  trillion years to finish counting.

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Macro, micro, submicro

• Macroscopic I can see with my naked eye
• Microscopic I need a microscope to see
• Submicroscopic I cant see even with the most
  powerful microscope

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Scanning Tunneling Microscope (STM)

• Although you cannot see atoms the STM can produce
  images on a computer screen that show the
  location of individual atoms.
• Platinum

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Using Models in Chemistry

• In chemistry you will use macroscopic and
  sub-microscopic models to understand certain
  concepts.
• Scientific model- a thinking device, built on
  experimentation, that helps us to understand and
  explain macroscopic observations.

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Models

• A model for the atom was discussed in Greece
  about 2,500 years ago. However, this was not a
  scientific model.
• The scientific model of the atom was not proposed
  until the 1800s and it has with stood much
  experimentation with little changes.

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Classifying Matter

• Matter can be classified by its composition
• There are two main types of classifications
• Qualitative- an observation made without
  measurement.
• Quantitative- an observation made with measurement

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Qualitative vs. Quantitative

• Qualitative
• There are students in this room
• Sucrose contains carbon, oxygen and hydrogen
• Quantitative
• There are 24 students in this room
• Sucrose contains 42.1 g of carbon, 51.4 g of
  oxygen and 6.5 g of hydrogen.

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Pure vs. Mixture

• Matter can be classified by its purity.
• Is the matter pure or is it a mixture?
• Pure in chemistry means it contains only the same
  substance.
• Substance- matter with the same fixed composition
  and properties.
• Can be an element or a compound
• Any sample of pure matter is a substance

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Substances

• The bag of sugar you buy at the store is pure
  sucrose. It all has the same properties and a
  fixed composition. Therefore, it is a substance.

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Mixed Matter

• Mixed matter is referred to as a mixture.
• Mixture- combination of two or more substances in
  which the basic identity of the substances are
  not changed.
• Mixtures do not have a specific composition.
• Mixtures can be separated into its components by
  physical means.

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Separating Mixtures

• One way is by physical changes.
• Physical change- a change in matter that does not
  involve a change in the identity of individual
  substances.
• Boiling
• Freezing
• Melting
• Evaporation
• Dissolving
• Crystallization

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Physical Properties

• Separation by physical changes takes advantage of
  the physical properties of the mixture.
• Physical properties- characteristics that a
  sample of matter exhibits without any changes in
  its identity
• Solubility
• Melting and boiling point
• Color
• Density
• Electrical conductivity
• Physical state (solid, liquid or gas)

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Types of Mixture

• There are two types of mixtures
• Heterogeneous
• Hetero means different
• Homogeneous
• Homo means the same

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Heterogeneous Mixture

• Heterogeneous Mixture- a mixture that does not
  have a uniform composition.
• You can see the different composition.
• Examples
• Granite
• Chef Salad
• Lucky Charms Cereal
• Orange Juice with pulp

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Homogeneous Mixture

• Homogeneous Mixture- a mixture with a uniform
  composition.
• You cannot tell that it is composed of more than
  one substance
• Another name is a solution
• Examples
• Salt water
• Tea
• Sugar water

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Solutions

• Homogeneous mixture
• Examples
• Salt water
• Gasoline
• Air
• Steel

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Alloys

• Alloys- solid solutions that contain different
  metals and sometimes nonmetallic substance
• Table 1.1 page 23

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Table 1.1 Some Common Alloys
Name of Alloy Composition
Stainless Steel 73-79 iron (Fe) 14-18 chromium (Cr) 7-9 nickel (Ni)
Bronze 70-95 copper (Cu) 1-25 zinc (Zn) 1-18 tin (Sn)
Brass 50-80 copper (Cu) 20-50 zinc (Zn)
Sterling Silver 92.5 silver (Ag) 7.5 copper (Cu)
14-karat gold 58 gold (Au) 14-28 silver (Ag) 14-28 copper (Cu)
18-karat white gold 75 gold (Au) 12.5 silver (Ag) 12.5 copper (Cu)
Solder (electronic) 63 tin (Sn) 37 lead (Pb)
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Solutions

• When you are dissolving a substance into another
  substance there are two important terms
• Solute the substance being dissolved
• Solvent the dissolving agent
• Salt Water
• Solute NaCl
• Solvent H2O

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Aqueous Solution

• Aqueous Solution- a solution in which the solvent
  is water.
• Examples
• Soda
• Tea
• Contact-lens cleaner
• Clear cleaning liquids
• Most processes of life take place in aqueous
  solutions.

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Substance Pure Matter

• You and everything around you is made up of
  chemicals.

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Elements The Building Blocks

• If you classify an unknown piece of matter as
  pure it means that it is made up of one
  substance
• There are two types of substances
• Compounds
• Elements

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Elements

• Elements- a substance that cannot be broken down
  into simpler substances.
• Simplest form of matter
• Building blocks for other types of matter
• All substance in the universe are
• Elements
• Compounds formed from elements
• Or mixtures of elements and compound

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Elements

• 118 elements
• Examples
• Gold
• Carbon
• Lead
• Elements combine to form millions of compounds.
• Chemical elements are often referred to as the
  building blocks of matter

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Elements

• 118 elements
• 90 occur naturally
• Less than half of these are abundant
• The remainder are synthesized

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Organizing the Elements

• Elements are organized in the Periodic Table
• The periodic table tells you
• Name
• Symbol
• Atomic mass

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Symbols

• The symbols of the elements are extremely
  important to know.
• You will only have to know the most common ones.
• The symbols are a one to two letter
  representation of the elements.
• Not all the symbols are the first or second
  letter of the elements name

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Symbols

• Oxygen
• O
• Hydrogen
• H
• Bromine
• Br
• Chlorine
• Cl

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Table 1.2 Some Historic Chemical Symbols
Element Symbol Origin Language
Antimony Sb Stibium Latin
Copper Cu Cuprum Latin
Gold Au Aurum Latin
Iron Fe Ferrum Latin
Lead Pb Plumbum Latin
Potassium K Kalium Latin
Silver Ag Argentum Latin
Sodium Na Natrium Latin
Tin Sn Stannum Latin
Tungsten W Wolfram german
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Compounds Are More Than One Element

• Compound a chemical combination of two or more
  different elements joined together in a fixed
  proportion.
• Every compound has its own fixed composition
• Therefore, every compound has unique chemical and
  physical properties.
• The properties of a compound are different from
  the properties of the elements that make them up.

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Compounds

• More than 10 million are known (still growing)
• New natural compounds are being isolated from
  plants and colonies of bacteria.
• New compounds are also being synthesized in labs.
• Examples
• Sucrose
• Salt
• Water

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Formulas of Compounds

• Formula a combination of the chemical symbols
  that show what elements make up a compound and
  the number of atoms of each element.
• Sucrose Aspartame

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Table 1.3 Some Common Compounds
Compound Name Formula
Acetaminophen C8H9NO2
Acetic Acid C2H4O2
Ammonia NH3
Aspartame C14H18N2O5
Propane C3H8
Salt NaCl
Sodium Hydroxide NaOH
Sucrose C12H22O11
Water H2O
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Review

• What is the difference between an element and a
  compound?
• What is the difference between a homogeneous
  mixture and a heterogeneous mixture?
• What is the difference between a mixture and a
  compound?