1what are the 7 steps to solving equilibrium problems?
reactions and conc of initial species, species at equilibrium, equilibrium relationships, mass balance, charge balance, proton condition, express all species as a function of [H+]
2buffers ____ a change in pH
resist
3most buffers are mixtures of _____ & their ______
weak acids, conjugate bases
4buffers are most effective when pH is _______
closest to their pKa because there is equal ability to give/take proton
5weak acids ______ dissociate at typical pH values
partially
6what are ionization fractions used to determine?
concentration distribution of acidase species
7what is an acid?
a compound that donates/yields protons upon addition to water
8what is a base?
a compound that accepts protons or yields hydroxide upon addition to water
9is h2o an acid or base?
h2o can react as both - it's ampoteric
10what is titration?
a method used to determine concentration of a particular substance in a water sample
11in titration, what does an equivalence point represent?
the equivalents of acid added is equal to the equivalents of base in original solution
12what is the importance of phosphorous in water?
essential for growth of organisms, it is usually the limiting nutrient in freshwater ecosystems, increase in P increases algae growth
13what can excessive phosphorous levels lead to?
eutrophication - algal growth
14what are the 3 sources of phosphorous in wastewater?
urine, detergent, fertilizer
15what are the 4 forms of phosphorous found in wastewater?
orthophosphates (reactive phosphorous), polyphosphates (2 or more orthophosphates linked together), metaphosphates (cyclic - not linear), organic phosphorous
16how is phosphorous measured in water?
colorimetric method with a reagent and spectrophotometer
17what is hard water?
water that contains high conentration of multi-valent metallic cations
18what does hardness reflect?
the geological formations the water has been in contact with
19what cations cause hardness?
calcium and magnesium - other divalent cations like iron and manganese which are usually negligible at pH of natural waters
20what are the problems associated with hard water?
scaling, soap demand, soap scum build up
21how is hard water fixed?
ion exchange
22what is the bromcresol green end point pH?
4.5
23what is the phenolphthalein end point pH?
8.3
24if total alk < total hardness, carbonate hardness =
total talk
25what does the subscript of alpha represent?
number of protons lost