Lab Final Study Guide 1-5

pH

indicates the intensity of acidic or basic character. the negative log of the hydrogen concentration.

turbidity

an expression of the optical property that causes light to be scattered and absorbed rather than transmitted.

causes of turbidity

clay, silt, fine organic and inorganic matter, plankton and other microorganisms

unit of measurement of turbidity

Nephelometric Turbidity Unit

ranges of acidic pH values

0-6

ranges of basic pH values

8-14

Two controls in pH standardization

intercept and slope

intercept control

sets the isopotential point by shifting the response curve laterally with no change in slope

slope control

rotates the response curve around the isopotential point without disturbing the intercept

axis definitions of pH curve

x-axis: pH, y-axis: slope

hardness

the total concentration of alkaline earth ions. cause by presence of dissolved polyvalent metal cations.

chelating agent

when a molecule has more than one "free" electron pair to be shared with metal ion

chelating agent used in Lab 2

EDTA

the sample solution is buffered to a ph of ---- as a compromise between chelate stability and precipitation prevention of Ca and Mg

10 +- 0.1

precipitates before pH of 10

CaCO3

precipitates at pH of 10

Mg(OH)2

chelating agent used to detect endpoint in Lab 2

EBT

temporary hardness

due to soluble salts: Ca2+ and Mg2+ as hydrogen carbonates

permanent hardness

due to chlorides and sulfates: Ca2+, Mg2+, Fe3+

hard water

makes soap less lather-able, can cause build up in pipes and residue on surfaces

EDTA titration color change

red to blue

alkalinity

measure of water's ability to neutralize acids/ maintain constant pH

the three species that cause alkalinity in water are

OH- , CO3 2- , HCO3 -

in Lab 3, if pH is larger than 8.3 add --- indicator

phenolphthalein

in Lab 3, phenolphthalein titration changes from --- color to ---color

pink to colorless

in Lab 3, if pH is smaller than 8.3, larger than 4.3 add --- indicator

methyl orange

in Lab 3, methyl orange titration changes from --- color to ---color

yellow to orange

equivalence point of acid mL vs pH graph

7

objective of coagulation-flocculation

turns small particles of color, turbidity, and bacteria into larger flocs

coagulation applies to the removal of ---

colloidal particles

colloids are stable because

they possess a negative charge that repels other colloids so they don't collide

collide movement is categorized as

Brownian Movement

what happens during coagulation

a positive ion is added into the water to reduce the surface charge to the point that colloids don't repel each other

two common coagulants

Al3+ and Fe3+

three properties of coagulants

trivalent cation, non-toxic, insoluble in neutral pH range

optimal pH range for coagulation

6.8-7.2

adequate pH range for coagulation

5-8

the final graph of Lab 4 plots

turbidity vs dosage

final coagulant dosages

0, 5, 7, 10, 15, 20 mg/L

rapid mixing speed of coagulants

250 rpm

slow mixing speed of coagulants

30 rpm

main objective of Lab 4

finding the optimum coagulant dosage

effect of too much nitrogen and phosphorus in water

causes algae to grow faster than ecosystems can handle (algae blooms)

algal blooms

large growths of algae that severely reduce or eliminate oxygen in water

algal blooms can make people sick if they

come into contact with polluted water, consume tainted fish or shellfish, drink contaminated water

nitrogen in polluted water is present in the form of

organic nitrogen and ammonia

total nitrogen (TN)

the sum of nitrate (NO3), nitrite (NO2), ammonia, and organic nitrogen

phosphorous occurs in wastewater bound to oxygen as

phosphates

which sources can produce phosphorus waste

agricultural fertilizers, domestic wastewater, detergents, industrial process wastes and geological formations

three types of phosphate classifications

orthophosphates, polyphosphates, and organic phosphates

to find Total Phosphorus

convert "combined" phosphate to ortho form for analysis

eutrophication

excessive plant and algal growth due to higher nutrients in the water.

what were the measurements that needed to be found in Lab 5

Total Nitrogen, Total Phosphorous, orthophosphates

how can agal blooms produce sickness in humans

if they come in contact with polluted water, eat polluted fish and shellfish, and drink contaminated water