Water & It’s Properties
The Molecule
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Water is a polar molecule
because it has a “positive”
and a “negative” side
Oxygen is greedy and hogs
the electrons, leaving the
hydrogens to be a little
positive
Slightly Negative
Slightly Positive
Hydrogen Bonds
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The positive and negative ends of the molecule
attract each other (up to 4 bonds – 2 to H’s 2 to
O’s)
Not as strong as ionic or
covalent
Causes cohesion
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Cohesion - attraction
between molecules of the
same substance
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Reason why water forms
beads on flat surfaces
Adhesion - attraction
between molecules of
different substances
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Reason why water forms
a meniscus in a graduated
cylinder
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Surface Tension:
combined effect of
adhesion and
cohesion
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(ex. Insect floating on
water)
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Hydrophilic – liking water; will dissolve in water
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Ex. Sugar, salt
Hydrophobic – fearing water; won’t dissolve in water
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Ex. oil
Mixtures
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Mixture – composed of 2 or more elements or
compounds that are physically combined but
NOT chemically combined. They can be
separated
Ex. Salt with pepper, sand with iron fillings
2 types of mixtures are solutions &
suspensions
1.
Solution – when particles are evenly
distributed throughout the mixture
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Has 2 parts:
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Solute – substance that is being dissolved
Solvent – substance doing the dissolving
Ex: Kool-aid, Chocolate Milk, Tea, Salt water
2 types of mixtures are solutions &
suspensions
2. Suspension – has water and undissolved
materials
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Ex. Blood, Italian Dressing, Muddy water