Hydrogen(+) Positive

H

Hydrogen(+) Positive

H

Oxygen(-) Negative

O

Water is a Polar MoleculeWater is a polar molecule. It has a (+) positive and

a (-) negative end.

As a result, each water molecule is like a little magnet.

This property causes water molecules to be very attracted to each other.

It also causes water molecules to be attracted to many other different polar molecules.

Water’s polarity is responsible for its unique properties that make it essential for life.

Water: The Universal SolventCapable of dissolving a variety of substances

Dissolves more substances than any other liquid

Wherever water goes, either through the ground or through our bodies, it takes along valuable chemicals, minerals, and nutrients.

Dissolving SaltWater can become so heavily attracted to

other polar molecules, like salt (NaCl), that it can disrupt the attractive forces that hold the sodium and chloride in the salt molecule together and, thus, dissolve it

Specific Heat Capacity The quantity of heat required to raise the

temperature of a unit mass of substance by one degree Celsius.

Water has a high specific heat meaning it takes a lot of heat to make it hot.Substance  Specific Heat (J/g oC)

 Air  1.01

Vegetable Oil 1.67

Rubbing Alcohol

2.60

Milk 3.93

 Water  4.18

How does that benefit life?

Water changes temperature very slowly

Helps us maintain our body temperature

Regulates the temperature in the atmosphere

Fish do not die because the temperature of water is able to stay somewhat the same from day to night

Why is the high specific heat capacity of water important?

Hydrogen Bonding in WaterHydrogen bonds hold water molecules

together (Animation). In water, a hydrogen bond is a relatively weak

attraction between the positively charged H atom in one molecule and the negatively charged O atom from another molecule.

• Hydrogen bonds are responsible for two types of attractive forces in water:

Cohesion and Adhesion

CohesionAttraction between like molecules

Water’s cohesiveness causes it to ball up into a sphere and stick together.

Surface TensionProperty caused by water’s cohesive

nature

Allows small objects to “float” on the surface as long as they do not break the surface

AdhesionAttraction between different molecules

Water’s adhesive properties cause it to spread out across and stick to the surface of an unwaxed car. Water adheres well to a painted surface but not to wax.

Capillary ActionTendency for a liquid to rise in

narrow tubes

Occurs as a result of adhesion and cohesion

Capillary action causes water to move high into trees

Properties of water in spacehttp://youtu.be/KFPvdNbftOY