Water Flashcards
high specific heat
the amount of heat that must be absorbed/lost for one gram of the substance to change temperature by 1°C.
water: 1 cal/g/°C
when heat is absorbed, hydrogen bonds are broken, when hydrogen bonds form, heat is released
-moderation of temperature in coastal areas - absorption and storage of heat from the sun in the daytime with minimal temperature change and release of heat due to gradually cooling water
-stabilize ocean temperatures, creating a favorable environment for marine life
-regulate temperature fluctuations on land and in water within limits that permit life
heat of vaporization
the quantity of heat a liquid must absorb for one gram of the liquid to be converted from liquid to gaseous state
hydrogen bonds must be broken before the molecules can make an exodus from liquid
-moderate Earth’s climate - solar heat absorbed by tropical seas is consumed by evaporation of surface water. As moist tropical air circulates poleward, it releases heat as it condenses to form rain
evaporative cooling
the surface becomes cooler during evaporation due to the loss of the molecules with the greatest kinetic energy to the gaseous state
-stabilizes the temperature of lakes and ponds and prevents terrestrial organisms from overheating (sweat, evaporation in leaves)
solute
a substance that is dissolved
solvent
the dissolving agent of a solution
aqueous solution
a solution in which water is the solvent
hydration shell
sphere of water molecules around each dissolved ion
molarity
number of moles of solute per liter of solution
molecular mass
the sum of the masses of all the atoms in a molecule
mole
6.02 x 10^23 of an object (Avogadro’s #)
one mole of a substance has the same number of ________ as a mole of a second substance
molecules
molecular mass is ________ to one mole
equal
i.e. molecular mass of surcrose is 342 daltons, so one mole of sucrose is 342 grams
acidification
release of carbon dioxide into the air that has changed the chemical composision of water found on Earth
-ocean acidification and acid precipitation
pH
calculated as the -log base 10 times [H+]
negative log of hydrogen ion concentration
a scale that compresses the range of H+ and OH- concentrations using logarithms
dissociation of water
creates acidic and basic conditions
-two water molecules connected by a hydrogen bond: a
hydrogen atom will move from one molecule to join the
other while leaving behind its electron. This creates a
hydrogen ion (H+) and a hydroxide ion (OH-)
