Properties of Matter

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Properties of Matter

• Chapter 2

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2.1 Classifying MatterOBJECTIVES

• Classify pure substances as elements or
  compounds.
• Describe the characteristics of an element the
  symbols used to identify elements.
• Describe the characteristics of a compound
• Distinguish pure substances from mixtures
• Classify mixtures as heterogeneous or
  homogeneous.

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Classifying Matter

• Pure Substances are matter that always has
  exactly the same composition.
• Every sample of a given substance has the same
  properties because a substance has a fixed
  uniform composition.

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Classifying Matter

• Elements
• Approximately 115 elements known to exist
• Are substances that cannot be broken down into
  simpler substances.
• Atoms are the smallest particle of an element
• An element has a fixed composition because it
  contains only one type of atom.
• At room temp most elements are solid.
• Chemical symbols
• C represent carbon O oxygen Fe? Mg?

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Classifying Matter

• Compounds
• A substance made from two or more simpler
  substances.
• Properties of a compound can greatly differ from
  the elements that it is made up of.
• Ex. O H are gases at room temp can fuel fire
  when combined chemically you get water.
• A compound always contains two or more elements
  joined in a fixed proportion.

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Classifying Matter

• Mixtures
• The properties of a mixture can vary because the
  composition of a mixture is not fixed.
• 2 Types
• Heterogeneous Homogenous

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Classifying Matter

• Heterogenous
• Particles are noticeably different from each
  other.
• Cheesburger
• Salsa
• Pizza

• Homogeneous
• Particles are evenly distributed difficult to
  tell them apart.
• Iced tea

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Classifying Matter

• Solution, Suspension, Colliods
• Based on size of its largest particles, how a
  mixture can be classified.

Solution A homogenous mixture where substances
completely dissolve.
Suspension A heterogeneous mixture that separates
into layers
Colloid Contains particles that are intermediate
in size between smaller larger particles in a
suspension.
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2.2 Physical PropertiesOBJECTIVES

• Describe physical properties of matter.
• Identify substances based on their physical
  properties.
• Describe methods used to separate mixtures.
• Describe evidence that indicates a physical
  change is taking place.

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2.2 Physical Properties

• Physical Properties
• Any characteristic of a material that can be
  observed or measured without changing the
  composition of the substances in the material.
• Viscosity, conductivity, malleability, hardness,
  melting point, boiling point, density.

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2.2 Physical Properties

• Viscosity
• A liquids tendency to keep from flowing.
• Conductivity
• Ability of a material to conduct heat /or
  electrical charge.

• Malleability
• The ability of a solid to be hammered into thin
  sheets.
• Hardness
• Measure of a materials ability to scratch
  another.

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2.2 Physical Properties

• Melting points
• Boiling points
• Freezing points

• Density
• Ratio of mass volume.
• Can be used to test the purity of a substance.

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2.2 Physical Properties

• Physical properties are used to identify a
  material, to choose a material for a specific
  purpose, or to separate the substances in a
  mixture.

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2.2 Physical Properties

• Separating Mixtures
• 2 common methods
• Filtration distillation

Filtration Process that separates material based
on the size of their particles. Brewing coffee
Distillation Process that separates the
substances in a solution based on their boiling
points. Desalinization alcohol production
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2.3 Chemical PropertiesOBJECTIVES

• Describe chemical properties of matter.
• Describe clues that indicate that a chemical
  change is taking place.
• Distinguish chemical from physical changes.

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2.3 Chemical Properties

• Chemical Properties
• Is any ability to produce a change in the
  composition of matter.
• Chemical properties can be observed only when
  the substance in a sample of matter are changing
  into different substances.
• Ex. FLAMMABILITY REACTIVITY

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2.3 Chemical Properties

• FLAMMABILITY
• A materials ability to burn in the presence of
  oxygen.
• Sometimes good
• Sometimes bad

• REACTIVITY
• Describes how readily a substance combines
  chemically with other substances.

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2.3 Chemical Properties

• Chemical Changes
• Occurs when a substance reacts forms one or
  more new substances
• Three common types of evidence that a chemical
  change is taking place
• Change in color
• Production of a gas
• Formation of a precipitate

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2.3 Chemical Properties

• Change in color
• Silver jewelry tarnishing
• Production of gas
• Baking soda used in cakes
• Formation of a precipitate
• Precipitate is any solid that forms separates
  from a liquid mixture.
• Curdled milk, rain, snow, sleet

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2.3 Chemical Properties

• Chemical or Physical Change
• Before deciding if a change is chem/physical ask
  the question Are different substances present
  after the change takes place?
• If YES it is CHEMICAL
• If NO it is PHYSICAL
• WHEN MATTER UNDERGOES A CHEMICAL CHANGE THE
  COMPOSITION OF MATTER CHANGES WHEN MATTER
  UNDERGOES A PHYSICAL CHANGE THE COMPOSITION OF
  MATTER STAYS THE SAME.

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MATTER
UNIFORM DISTRIBUTION
NO
YES
HETEROGENEOUS
HOMOGENEOUS
FIXED COMPOSITON
YES
NO
PURE SUBSTANCE
SOLUTION
CAN IT BE BROKEN DOWN
NO
YES
COMPOUND
ELEMENT