Water's Polarity

Polarity of water, and all the resulting properties.

1. The Properties of Water
primarily due to polarity

2. Terms to Know
• polarity
• hydrogen bond
• cohesion
• adhesion
• surface tension
• capillary action

3. Water
•Most abundant naturally occurring liquid
•Liquid at most Earth temperatures
•Unlike most liquids – it expands when
frozen
•The lower density of ice allows it to float
(4°C most dense)

4. Water  H
2
O
•As we know - water is neutral
•But because the O atom is
larger than the H atoms –
electrons spend more of their
time nearer the oxygen
•This gives water a slight overall
charge
•That charge is called polarity

5. Polar Bonding
•Polarity really does allow bonding
•They are hydrogen bonds and they
are very weak
•They last for fractions of a second
•Continuously break and reform

•Polarity really does allow bonding
•They are hydrogen bonds and they
are very weak
•They last for fractions of a second
•Continuously break and reform

6. Forces due to polarity
1.Cohesion
2.Adhesion

7. •The natural attraction of a water molecule
to other water molecules
is called cohesion

8. Cohesion
•Can be seen as water droplets form

9. •The attraction of a water molecule to
another polar molecule is adhesion
•Molecules such as soil and clay (dust)
•Surfaces like glass or paper straws
•Certain clothing fibers and … animal hair

10. Adhesion
•Can be seen as water droplets form on the
spider web (another polar surface)

11. •Two simple properties associated

with polarity are
Capillary Action
Surface Tension

12. Capillary Action
1.We know that gravity is ALWAYS pulling on
objects with mass
2.Yet water can move up a paper towel with
relative ease - How can this happen?
3.Because the positive and negative charges in
the paper attract the polar water molecules
(adhesion)
4.This property of adhesion is called capillary
action

14. Surface Tension
2.Inside a drop of water polar water molecules attract to
each other in a random fashion
3.At the surface of the drop, water does not attract to the
air
4.A unified layer of molecules at the surface creates
surface tension
5.There the water behaves like an flexible sheet allowing
denser objects to “sit” on the surface

15. Surface Tension

16. Review
Polarity  hydrogen bonding

cohesion adhesion
surface tension capillary action
Forces
PropertiesProperties
Forces

17. The End

polarity