2.2 water Flashcards
Hydrogen bond
A weak intermolecular force between two polar molecules. The oxygen in one water molecule hydrogen bonds with the hydrogen of another water molecule
Intermolecular force
An attraction between two molecules
Energy (Joules)
Allows for work (ex: heat and kinetic energy)
Boiling point
The temperature at which liquid becomes a gas (100 degrees C in water)
Melting point
The temperature a solid becomes a liquid (0 degrees C in water)
Specific heat capacity
The amount of energy required to raise the temperature of 1g of a substance by 1 degree Celsius
Latent heat of vaporization
The amount of energy needed to evaporate a substance at its boiling point
Evaporation
Liquid to gas
Solvent
A substance that dissolves another substance
Solubility
Having the ability to dissolve
Cohesion
Attraction between two molecules of the same kind
Adhesion
Attraction between two different molecules or surfaces
Covalent bonds
When they share electrons (ex: oxygen and hydrogen share electrons)
What is electron-greedy? (Electronegative)
When an element has a high affinity for electrons so it tends to pull electrons towards its nucleus (like oxygen)
Is hyrdogen electron-greedy?
No, it only has one proton in its nucleus so it doesn’t hold electrons very well
What symbol represents being negatively or positively charged?
Delta
What is polar molecule called?
A dipole
Up to how many h-bonds can a water molecule form?
4
What can a positively charged hydrogen atom form an h-bond with?
A negatively charged fluorine, oxygen, or nitrogen atom of another molecule
Why does water have high surface tension?
Bc it sticks to itself (it’s cohesive)
Why does water have a high heat capacity?
Bc it takes a lot of energy to break a hydrogen bond and cause the water molecules to start evaporating
What must happen before a change if state can occur?
Hydrogen bonds must be broken
Why is water an excellent medium for living organisms?
It is slow to change temperature and thus supports the maintenance of constant conditions
Water vs Methane
- Water is polar
- can form intermolecular hydrogen bonds
- hydrogen bonds b/w molecules absorb heat energy, reducing kinetic energy