Beyond the EU: DORA and NIS 2 Directive's Global Impact
Properties of water lesson
1.
2.
3.
4. 1. Cohesion & adhesion
2. Low density solid
3. Solubility: a good solvent
4. High specific heat capacity
5. High heat of vaporization & fusion
6. Ionization: determines pH
5. Cohesion:
the clinging of a substance to itself
hydrogen bonds between water molecules
holding water together
Adhesion:
the clinging of one substance to another
E.g. Meniscus: hydrogen bonds between
water molecules and the glass of a test tube
6.
7. A measure of how difficult it is to break the
surface of a liquid
Surface tension is one of the results of
cohesion in water
Video:
A National Geographic video showing how a lizard employs the
8. Water is most dense at 4oC
Ice is less dense than water
Water is the only type of
matter which becomes less
dense when a solid
9.
10. Aquatic life
When the temperature
of the atmosphere falls
below 0oC, the water at
the surface gradually
freezes to ice
The water under the ice
remains at 4oC
11. Amount of heat energy needed to increase
the temperature of a substance by 1oC
Water has a high specific heat capacity:
Water is capable of absorbing a lot of heat
without increasing in temperature
Demonstration: water balloon
12.
13. Help organisms maintain constant body
temperature
Large bodies of water have moderating
effect on nearby land temperature
14.
15. Heat of vaporization: amount of heat a
liquid must absorb to be converted to a gas
Heat of fusion: amount of heat a solid must
absorb to be converted to a liquid
Water has high heat of both vaporization and
fusion
Relevance: sweat
16. Hydration shell
Some biologically significant solutes
include salts, sugars, proteins, vitamins
19. Many molecules are able
to dissolve in water.
Organic matter may be
hydrophilic or
hydrophobic.
20. H2O H+ + OH-
Reversible
pH = -log[H+]
Relevance: Organisms are very sensitive to
pH changes
21. Is water an acid or a base?
H 2O + H 2O H3O+ + OH-
22. Is water an acid or a base?
conjugate
base acid
H 2O + H 2O H3O+ + OH-
acid conjugate
base
23. Acid
compounds that will donate a proton in solution
results in a negative charge
Base
compounds that will receive a proton in solution
results in a positive charge