Unit 4
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Two or more substances together
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Mixture of two solids
◦ Spoonful of salt mixed together with a spoonful of
baking soda.
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Mixture of two liquids
◦ Cup of olive oil and a cub of vinegar
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Mixture of a solid and a liquid
◦ Sand in an aquarium full of water
Salt
Baking
Soda
Salt and Baking
Soda Mixture
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Simplest kind of interaction
Pieces of the two substances are randomly
interspersed and they come to rest against
one another
Two kinds of particles coexist and are
completely unaffected by being close with
one another
Two substances are still identifiably distinct
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When mixed and shaken, the two liquids are
distributed throughout one another in tiny
droplets
When mixing stops, the two substances rejoin
other droplets of their own kind and
reassemble themselves into two individual
substances
Two substances are still identifiably distinct
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Water still a pure continuous mass, but now
infused with sand chunks
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When mixing stops, gravity pulls on sand to
settle at the bottom
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Every surface of the sand is in contact with
the water
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Substances still coexist independent of one
another
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To incorporate one substance uniformly into
another substance at the particle level
Example
◦ Sugar and water
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A mixture formed when one substance
dissolves in another
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What dissolves is known as the solute
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What the solute dissolves into is the solvent
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Between the sugar and the water, which is the
solute and which is the solvent?
Solute?
Sugar
Solvent?
Water
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The Air
◦ Solvent Nitrogen gas
◦ Solute Oxygen gas
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Brass
◦ Solvent Copper
◦ Solute Zinc
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Copper (Solvent) + Zinc (Solute) = Brass
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The amount of solute dissolved in a measure
of solvent
Imagine two beakers with 100 mL of water in
each. One has 5g of sugar, the other 10g of
sugar
5g Sugar
10 g Sugar
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How are the two solutions the same?
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Answer
◦ Both contain water and sugar
◦ Both are clear
◦ Same amount of Water
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How are the two solutions different?
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Answer
◦ Amount of solute (sugar)
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1st – Mass Ratio
◦ Ten grams of sugar in 90 g of water produces a
10% sugar solution
 Total mass = 10g + 90g = 100g
 10g sugar divided by 100g = 10%
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2nd – Parts per thousand or Parts per million
◦ Every liter (1000mL) of seawater contains 19 g of
chlorine particles.
◦ So there are 19 parts per thousand of chlorine in
seawater
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Saturated – a solution with the maximum
amount of dissolved solute
A fixed amount of water will dissolve a
certain amount of sugar.
If more sugar is added, it will not dissolve,
but fall to the bottom of the container.