Unit 1: Water Flashcards
Hydrophilic
Water loving: molecules that are polar, charged or ionic.
Hydrophobic
Water fearing: molecules that are nonpolar compounds
Properties of water (3)
ice is less dense than water, high specific heat capacity, high heat of vaporization
Reactant
the starting materials in a chemical reaction (to the left of the arrow)
Products
the materials produced in a chemical reaction (to the right of the arrow)
Arrows might show two things:
React to make or form
Water generates charges because
oxygen is more electronegative than hydrogen
Solvant
something that is capable of dissolving another (polar) substance
Dissociation
atoms or groups of atoms break off from molecules and form ions
Water molecules sticking to each other is
Cohesion (because of hydrogen bonding)
Surface tension
the capacity of a substance to withstand rupturing when placed under tension or stress
Adhesion
attraction to other charged, polar molecules
What force allows plants to transport water from their roots to their leaves
Adhesion
What happens when the heat rises as water boils
the water molecules’ higher kinetic energy causes the hydrogen bonds to break completely and allows water molecules to escape into the air as gas
What happens when water freezes?
the water molecules form a crystalline structure maintained by hydrogen bonding (there is not enough energy to break the hydrogen bonds)
What has the highest specific heat capacity of any liquids
Water
high heat of vaporization
the amount of energy required to change one gram of a liquid substance to a gas
Evaporation
Individual water molecules acquire enough energy from other water molecules such that some surface water molecules can escape and vaporize
Equation to calculate pH
pH = -log[H+]
[H+]
molar concentration of hydrogen ions
Non-neutral pH readings result from
dissolving acids or bases in water
Low concentrations of hydroxide ions OH- yields
a low pH number, high acidity
Low levels of hydrogen -[H] ions result in
high pH, low acidity
The pH scale ranges from
0 (high pH) to 14 (low pH). Anything above 7 is alkaline/basic.
Buffers and bases are both
substances that resists a change in pH by readily donating OH– or taking up [H+]. Resisting change doesn’t mean neutral but just regulated.
a substance with many polar covalent bonds will be
hydrophilic
C-C,
C-H
non polar covalent bonds, hydrophobic
O-H,
O-C
polar covalent bonds, hydrophillic
[ ] brackets tell us
it is a concentration
What kind of compounds dissolve well in water?
Charged, ionic, polar
What type of bonds will maintain proteins shape and structure? (2)
Hydrogen and ionic
Hydrogen bonds play a role in water molecules through
adhesion, cohesion and solvent properties
