Pure Substances and Mixtures

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Pure Substances and Mixtures

• Review Notes for Quiz

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THE PARTICLE THEORY

• Everything is made of particles with spaces
  between them, particles are always moving and
  particles are attracted to each other.
• SOLIDS Particles are close together, very
  attracted to each other, locked in a pattern and
  vibrate in place.
• LIQUIDS Particles are slightly farther apart,
  less attracted to each other and are able to
  slide past each other.
• GAS Particles are far apart and can move in any
  direction because the attractive forces are weak.

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PURE SUBSTANCES AND MIXTURES

• A pure substance contains only 1 type of particle
  throughout (Diamonds, distilled water). Pure
  substances rarely occur naturally and most are
  separated from raw material by people.
• A mixture contains 2 or more types of particles
  (2 or more pure substances) throughout (air, salt
  water, salad). Most substances are mixtures.

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TYPES OF MIXTURES

• Heterogeneous mixtures (mechanical mixtures) are
  made up of 2 or more types of particles and you
  can see or feel the different types of particles
  (ex. strawberry jam, salad)
• Homogeneous mixtures (solutions) are made up of 2
  or more types of particles but look and feel like
  only 1 type of particle (ex. apple juice, sugar
  and water).

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• Solutions are made up of at least one solute and
  one solvent.
• The solute is the substance that gets dissolved
  (kool-aid powder).
• The solvent is the substance that does the
  dissolving (water).
• Solutions can be made up of any combination of
  solid, liquid or gas (eg Pop is made up of liquid
  water, solid sugar and gaseous carbon dioxide).

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HOW DO SOLUTIONS FORM?

• When particles of one substance are more
  attracted to particles of another substance than
  they are to themselves, they will form a
  solution.
• In this situation, particles on the surface of
  the solute will break away and begin to fill the
  spaces between the solvent particles until all
  the solute particles are evenly mixed between the
  solvent particles.

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THE RATE OF DISSOLVING

• The rate of dissolving refers to how fast a
  solute dissolves (mixes) in a solvent.
• We discovered 3 factors that increase the rate of
  dissolving movement (stirring), increasing the
  solvent temperature and crushing the solute.

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Dilute/Concentrated

• The concentration of a substance is how much
  solute there is compared to solvent.
• A solution with a low concentration is dilute.
• A solution with a high concentration is
  concentrated.
• Concentration can be calculated using the
  formula Amount of Solute x100
• Amount of Solvent
• Concentration is measured in percent

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Saturated/Unsaturated

• Saturated When there are no more spaces between
  the solvent particles for solute particles to
  dissolve. No more solute can dissolve in the
  solvent
• Unsaturated When there are still spaces between
  the solvent particles for more solute particles
  to dissolve into the solvent.

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• Supersaturated A solution that contains more of
  the solute than would normally be found in a
  saturated solution at that temperature. This is
  created by heating a solvent and saturating it,
  and then slowly cooling it without disturbing the
  solution so that the solute stays dissolved at
  the cooler temperature.
• Solubility The amount of solute that will
  dissolve in a particular solvent at a certain
  temperature. Sugar has a higher solubility than
  salt because more sugar can dissolve in 100mL of
  water than salt at the same temperature. This is
  because sugar particles are smaller than salt
  particles.

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Household Hazardous Waste Symbolssee page 55

• Red/Danger
• Orange/Warning
• Yellow/Caution

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WHMIS Symbolssee page 55

• WHMIS stands for Workplace Hazardous Materials
  Information System.