Chapter 3: Matter

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Chapter 3 Matter
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Chapter Outline

• Describing matter
• Physical states of matter
• Physical and chemical properties
• Composition
• Pure substances - Elements and compounds
• Mixtures - Homogeneous and heterogeneous
• Separating matter based upon differences in
  physical properties
• Filtration and distillation

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Physical States of Matter

• States of matter
• Solid
• Liquid
• Gas
• Plasma (not covered)

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Physical States of Matter

• A substances state of matter is related to the
  strength of the attractive forces among the
  matters particles
• E.g. solids have very strong attractive forces
  between particles and gases very weak forces

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Solids

• Shape
• fixed/definite
• Volume
• fixed
• Varies slightly with temperature
• Particles are closely packed, rigidly arranged,
  and strongly attracted to each other

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Liquids

• Shape
• A liquid takes the shape of the bottom of the
  container up to the volume it fills
• Volume
• fixed/definite
• Varies slightly with temperature
• Particles are sliding over each other and
  moderately attracted to each other

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Gases

• Shape and Volume
• A gas takes the shape and volume of a closed
  container
• Gases expand or compress to fill a closed
  container
• Gas particles are far apart, moving very rapidly
  as they bounce off each other and the walls of
  the container
• Gas particles are very weakly attracted to each
  other

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Change of State

• Increasing the temperature of a substance
  increases the kinetic energy of its particles
• Kinetic energy energy of motion
• A change of state occurs when the energy of the
  particles is greater than the forces that hold
  the particles together at a given state

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Properties of Matter

• Physical property characteristic of a substance
  that can be determined without changing the
  chemical composition of the substance
• Examples

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Properties of Matter

• Chemical property ability of a substance to
  form new substances
• Always involves a change in chemical composition
  of the substance
• Examples

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Related Terms

• Physical change
• Change in a substances physical properties
  without a change in chemical composition
• Examples

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Related Terms

• Chemical change
• Change in a substances chemical composition
• Also called a chemical reaction

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Composition of Matter

• Pure Substance - matter with definite composition
• Elements and compounds are pure substances
• Mixture matter with variable composition

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Pure Substances

• Elements substance that cannot be broken down
  into other substances by chemical means
• Examples see periodic table

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Pure Substances

• Compounds 2 or more (different) elements joined
  in a definite ratio
• Compounds can be broken down into elements by
  chemical means
• Examples

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Pure Substances

• The properties of compounds are different from
  those of the elements it contains.
• Example

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Mixtures

• Mixture matter with variable composition
• 2 or more pure substances mixed together
• The components of a mixture are not joined to
  each other in any fixed ratio
• example

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Mixtures

• Homogeneous mixture
• Mixture with the same properties throughout
• Also called a solution
• Examples
• Heterogeneous mixture
• Mixture with regions that have different
  properties
• Examples

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Separating Mixtures

• Most matter in the world is a mixture
• To separate the components of a mixture, chemists
  take advantage of differences in the physical
  properties of the mixtures components.
• Not always easy!

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Separating Mixtures

• Filtration
• Used to separate a solid from a liquid in a
  heterogeneous mixture
• Page 60
• Can filtration be used to separate sugar from
  water in sugar water?
• Why or why not?

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Separating Mixtures

• Distillation
• Separates mixtures based upon differences in
  volatility
• Volatility
• Volatility is related to a substances boiling
  point
• A highly volatile substance will have a _______
  boiling points.

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Distillation

• Distillation works best when there is at least a
  100 C difference in boiling points.
• Consider a mixture of water and ethanol.
• Boiling point water ____________
• Boiling point ethanol ______________

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Distillation Apparatus
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Distillation

• Heat the mixture to the b.p. of the substance
  with the lower b.p.
• Change of state occurs
• Ethanol becomes a gas
• Ethanol vapors expand to fill the distillation
  apparatus

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Distillation

• Ethanol gas enters the water cooled condensing
  tube
• Change of state occurs as the ethanol is cooled
  below __________
• Ethanol gas condenses and forms a liquid
• Ethanol liquid drips into the collecting container

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Distillation

• Temperature shoots up to the bp of water
• Change of state occurs
• Water becomes a gas
• Water vapors expand to fill the distillation
  apparatus
• Water vapors enter the condensing tube
• Water condenses to form a liquid

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Summary

• See Board.
• Compare to diagram on page 61