Water Flashcards
What is water made up of ?
2 Hydrogen atoms and one oxygen
What is the charge of a water molecule ?
No over all charge, but the oxygen has a slight negative charge and the hydrogen a slight positive charge
Why is water a dipolar molecule ?
The oxygen atom has a slight negative charge, while the hydrogen atoms are slightly positive charge. Therefore water has both negative and positive poles
What is the meaning of diplomar?
Has both negative and positive poles
What is the attractive force between opposite charges called ?
A hydrogen bond
Describe what is a hydrogen bond is
The attractive force between opposite charges
How strong is a hydrogen bond?
Relatively weak being about a tenth of the strength of a covalent bond
How are water molecules stuck together ?
Hydrogen bonds
Why does water have a higher boiling Point than predicted ?
There are huge numbers of hydrogen bonds, so it takes a lot of energy to separate them.
What is the specific heat capacity of a substance ?
The amount of energy needed to change the temperature of 1 kg of the substance by 1°.
What is the specific heat capacity of water ?
4190jkgC
What is latent heat of vaporisation ?
The amount of energy required to evaporate 1 kg of water.
What must happen for a substance to change from a liquid to a gas.?
The potential energy stored in the forces between molecules needs to be overcome by the kinetic energy of the motion of particles
What is cohesion ?
The tendency of molecules of the same substance to stick together.
Why does water have large cohesive forces?
Hydrogen bonding
What is surface tension?
When water meets Aircon the water molecules tend to be pulled back into the body of water, rather than escaping it. This force is know as surface tension
What does surface tension mean?
The water acts like a skin and a strong enough for a small organisms such as pond skaters to be supported on the water surface
Name the reactions where water is used or made
hydrolysis- water us used
condensation- water is made
What property of water allows substances to dissolve and move freely for metabolic reactions to take place?
water as a solvent
Name the substances water readily dissolves
- respiratory gases
- excretory products
- inorganic ions
- small hydrophilic molecules
Explain what property of water keeps the pond skater floating?
Cohesion and surface tension
when water meets air the water tends to be pulled back into the body of water
water acts as a skin
How do plants rely on cohesion and surface tension?
Water must be pulled up the xylem tissues
