Chem 112 Lab Final Experiment 9

Front 1

the ______ of the water in the _____ was modeled

Back 1

salinity profile

San Antonio Bay

Front 2

samples were collected in

Back 2

march, a wet month, and april

Front 3

the salinity was calculated from an experimentally determined

Back 3

chloride ion concentration

Front 4

what was the titrant used

Back 4

silver nitrate

Front 5

what factors are important in determining the biological health of the ecosystem (4)

Back 5

temp, pH, salinity, turbidity

Front 6

the san antonio bay is fed by

Back 6

the guadalupe river

Front 7

salinity

Back 7

the amount of salt dissolved in a samples of water

Front 8

salinity is typically reported in

Back 8

grams salt per liter samples or parts per thousand (ppt)

Front 9

the most abundant dissolved salt in seawater is

Back 9

sodium chloride, NaCl

Front 10

equation for ppt NaCl concentration

Back 10

g NaCl/g salt water x 1000

Front 11

on average the salinity of oceanic waters is

Back 11

35 ppt

Front 12

river have an average salinity of

Back 12

1.6 ppt

Front 13

the salinity profiles of bays and estuaries show

Back 13

a large variance in salinity according to location, time of day, and time of year

Front 14

the weight of NaCl in a saline solution can be calculated if

Back 14

the chloride ion concentration in molarity is known [Cl-]

Front 15

silver nitrate symbol

Back 15

AgNO3

Front 16

solubility rules tell us that silver ions (Ag+) will

Back 16

form an insoluble solid when reacted with chloride ions (Cl-)

Front 17

what is AgCl

Back 17

a white silver chloride precipitate

Front 18

before the equivalence point there is an excess of

Back 18

the chloride ion

Front 19

at the equivalence point,

Back 19

all the chloride ion has reacted and the precipitate ceases to form

Front 20

after the equivalence point,

Back 20

the excess silver ion concentration increases

Front 21

titrations using silver nitrate can be called 2 things

Back 21

argentometric titrations

precipitation titrations

Front 22

argentometric methods have been used in the determination of (6)

Back 22

halides, thiocyanate, cyanide, mercaptans, inorganic anions, fatty acids

Front 23

the equivalence point of a precipitation titration is defined as being the point at which

Back 23

the precipitate no longer forms

Front 24

brightly colored adsorbent species or precipitates

Back 24

chemical indicators

Front 25

Fajan's method relies on the use of

Back 25

an adsorbtion indicator, dichlorofluorescein

Front 26

dichlorofluorescein is a

Back 26

weak organic acid

Front 27

adsorption indicators form a _____ as they adsorb to the surface of particles in solution

Back 27

colored layer

Front 28

the silver chloride particles that form before the equivalence point will adsorb the _____ over the ____

Back 28

excess chloride ions

indicator anions

Front 29

what prevents the adsorption of the dichlorofluoresceinate anions (Ind-)?

Back 29

the negative charge of Cl- around the AgCl molecule

Front 30

once the equivalence point is reached, _____ begin to adsorb on the surface of the precipitate

Back 30

Ag+ ions

Front 31

dichlorofluoresceinate anions form a ___ layer as they adsorb to the ______

Back 31

pink

Ag+ ions

Front 32

what happens to silver cations in bright light

Back 32

they are reduced to silver metal

Front 33

silver solutions containing a fine gray precipitate, reduced silver,

Back 33

should not be used

Front 34

what promotes more adsorption of the indicator and results in sharper endpoints

Back 34

increasing the precipitate surface areas

Front 35

the addition of what to the analyte solution prevents the silver chloride particles from coagulating

Back 35

the carbohydrate dextrin

Front 36

waste containing silver will

Back 36

be collected in waste jars

Front 37

what did we do before titrating the bay water samples

Back 37

titrated a standard NaCl solution

Front 38

when using Fajan's method the endpoint is more clearly seen when

Back 38

the indicator is added close to the endpoint

Front 39

the solution will change from _____ to _____

Back 39

orange/tan

milky pink

Front 40

what is performed to determine the approx endpoint

Back 40

a fast titration

Front 41

a calculated endpoint volume of less than 1 mL AgNO3 indiciates that

Back 41

the sample being titrated is too dilute

Front 42

true or false. if you arrive late, you will be able to take the make-up quiz in 412 held

Back 42

false

Front 43

true or false. if you drop chem 102 you have to drop 112

Back 43

false

Front 44

formula unit equation?

Back 44

NaCl(aq) + AgNO3(aq) <=> AgCl(s) + NaNO3(aq)

Front 45

total ionic equation?

Back 45

Na+(aq) + Cl-(aq) + Ag+(aq) + NO3-(aq) <=> AgCl(s) + Na+(aq) + NO3-(aq)

Front 46

net ionic equation?

Back 46

Ag+(aq) + Cl-(aq) <=> AgCl(s)

Front 47

we assumed that density of bay water was

Back 47

1 g/mL

Front 48

real data was collected by ______ in the ______ at tamu

Back 48

dr. stephen davis

department of wildlife and fisheries sciences

Front 49

practical salinity is determined by measuring the

Back 49

conductivity of water samples

Front 50

conductivity of water is directly related to

Back 50

salt (electrolyte) concentration

Front 51

what connects the gulf of mexico to san antonio bay

Back 51

ayers bay

Front 52

water flows from ____ to ____ thru ayers bay

Back 52

san antonio bay

gulf of mx

Front 53

there is a higher salinity in the bay in

Back 53

April