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physical and chemical properties of water.
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Properties of water
Polar molecule
cohesion
adhesion
high specific heat capacity
high latent heat for vaporisation
ice is less dense
universal solvent for life
Polar molecule
It has uneven number of charges
the O atom is slightly negative
the H atom is slightly positive
The number of hydrogen bonds a water molecule can form…
…upto four neighbours
Hydrogen bonds form, break and reform…
…at great frequency
Numerous hydrogen bonds makes it a…
…very stable structure
Cohesion
Water molecules are attracted to each other and form hydrogen bonds
they move together as a chain
Adhesion
Water molecules stick to surfaces
due to the polarity it gets attracted to other charged or polar substances
Surface tension
a measure of the force necessary to stretch or break the surface of a liquid
Water behaves as if…
…it is covered by invisible film
High specific heat capacity
The amount of heat that may be absorbed or lost for 1 kg of a substance to change its temperature by 1’C
Water has a specific heat capacity of…
…4200J/kg’C
Water doesnt change temperature drastically so…
…this can be used to maintain a suitable temperature
Water can absorb/release relatively large amounts of heat…
…with only a slight change in its temperature
High latent heat of vaporisation
the thermal energy required to convert a specific amount of a substance from a liquid to a gas at a constant temperature and pressure
This is responsible for…
moderating earths climate
stabalising temperature in aquatic ecosystems
preventing organisms from overheating
Density
The mass of a substance per unit volume
most dense at 4’C
expands from 4’C to 0’C
Ice forms from…
…top to bottom
Solution
solute and solvent
Aqueous solution
solution in which water is the solvent
Hydrophylic
form hydrogen bonds with water
Hydrophobic
cant from bonds with water
hydrocarbons