Chapter 2 Classification of Matter

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Chapter 2Classification of Matter

• Objectives
• Define and give examples of 3 states of matter
• Distinguish between substances and mixtures
• Understand what elements are
• Distinguish between metals, nonmetals and
• metalloids
• Define compounds and diatomic molecules

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What is Matter?

• Anything that has mass and occupies space
  (volume)
• Composed of atoms
• Exists in three states on earth
• Solid
• Liquid
• Gas
• Exists in fourth state in space
• Plasma (An electrically neutral,
• highly ionized gas state)

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Solids

• Definite shape and volume
• Particles tightly packed in a lattice pattern
• Crystalline salt, sugar, quartz
• Amorphous solids no regular, geometric pattern
  eg. Glass, plastic, gel

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Liquids

• Definite volume
• Not a definite shape (Takes shape of container)
• Particles have more energy
• Particles can move freely

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Gases

• Indefinite volume
• No definite shape
• Particles have high energy level
• Particles move independently of one another

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Classfication Flowchart
MATTER
yes
no
Can it be physically separated?
Compound
Heterogeneous Mixture (mechanical)
Homogenous Mixture (solutions)
Element
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Substances and Mixtures

• Pure Substance a particular kind of matter with
  a definite, fixed composition
• Elements (copper, gold, oxygen)
• Compounds (sugar, salt, water)
• Mixture a blend of two or more pure substances
• NOT chemically combined

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Types of Mixtures

• Heterogeneous mixtures
• Visibly different parts
• Eg. Chocolate chip cookies granite
• Two or more phases (usually)
• Homogeneous mixtures
• Different parts not visible (uniform throughout)
• One phase
• Eg. Sea water, air

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Homogeneous Mixtures

• Also known as solutions
• very small particles (0.2 2.0 nm)
• no Tyndall effect (particles dont scatter light)
• particles dont settle
• Eg rubbing alcohol, air,
• brass alloy

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Colloids

• Homogeneous or heterogenous? Difficult to
  say
• medium-sized particles
• (2.0 1000 nm)
• Tyndall effect
• particles dont settle
• Eg milk

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Suspensions

• large particles (gt1000 nm)
• Tyndall effect
• particles settle
• Eg fresh-squeezed lemonade

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Heterogeneous Mixtures

• Mechanical
• Several components mixed and visible
• Eg Raisin Bran

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Pure Substances

• Elements
• A substance that cannot be separated into simpler
  substances
• Compound
• Two or more elements combined through a chemical
  reaction
• Different properties than elements which compose
  it

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Elements

• Classificiation
• Metal
• Nonmetal
• Metalloid

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Elements

• Metals
• Usually solid at room temp
• Good conductors of heat and electricity
• High luster (shiny)
• Ductile easily pulled into wires
• Malleable easily beaten into thin sheets
• High melting point high density
• Usually dont combine with each other
• Readily combine with nonmetals

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Elements

• Nonmetals
• Solids (C, P, S, Se, I2) Liquid (Br2) Gases
  (all others)
• Poor conductors of heat and electricity no
  luster
• Low melting point low density
• Will combine with each other (CO2)
• Will combine with metals or metalloids
• Some found uncombined in nature (noble gases)

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Elements

• Metalloids
• Have properties of both metals and nonmetals
• Some used for semiconductors in electronics
• Eg Silicon, Germanium

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Compounds

• Two or more elements chemically combined
• New properties
• Definite proportions
• Can be chemically separated
• Molecular (covalent) or Ionic

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Compounds

• Molecular
• Held together with covalent bonds
• Molecule smallest uncharged individual unit of
  a compound
• Eg. Water, carbon dioxide

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Compounds

• Ionic
• Ion positively or negatively charged atom or
  group of atoms
• Cation positive
• Anion negative
• Held together by ionic bond attraction between
  positive and negative charges

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Diatomic Molecules

• Always exist as 2 atoms
• 7 naturally occurring
• Hydrogen, oxygen, fluorine,
• bromine, iodine, nitrogen,
• chlorine
• H2, O2, F2, Br2, I2, N2, Cl2
• Memory tool HOFBrINCl pronounced
  Hoffbrinkle

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Chemical Formulas

• Subscript indicates of atoms present
• H2O has 2 Hydrogen atoms and 1 Oxygen atom
• H2SO4 has
• NaOH has
• C6H12O6 has

2 hydrogen atoms, 1 sulfur atom, 4 oxygen atoms
1 sodium atom, 1 oxygen atom, 1 hydrogen atom
6 carbon atoms, 12 hydrogen atoms, and
6 oxygen atoms
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Separating Mixtures

• Do NOT cause chemical changes
• Heterogeneous Mixtures
• Filtration

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Separating Mixtures

• Homogeneous Mixtures
• Distillation

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Separating Mixtures

• Homogeneous Mixtures
• Chromatography

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Separating Mixtures

• Homogeneous Mixtures
• Crystallization