Lecture 15-16

Question 1

pE=

Answer 1

E/0.0591

Question 2

sediments are commonly formed from what?

Answer 2

precipitation reactions

Question 3

alternating layers of CaCO3 (s) and FeS(s) in lake sediment, why does it alternate like that?

Answer 3

CaCO3 produced as a byproduct of photosynthesis during the summer and FeS produced by the bacterially-mediated reduction of Fe(3) and SO42- during the winter.

Question 4

Black Carbon comes from what?

Answer 4

combustion of petroleum/biomass and found in atmosphere, soil and sediments

Question 5

what is colloidal particles:

Answer 5

Usually small particles on the size of 1nm to 1um

Question 6

what is the tyndall effect?

Answer 6

shining light and seeing colloidal particles! Can estimate how many based on the scattering of light.

Question 7

triangle E degree=

Answer 7

E degree red- E degree Ox

Question 8

water + salt is a recipe for what?

Answer 8

rust!

Question 9

Qe=

Answer 9

((Co-Ce) x V)/m

Question 10

typically find sulfate ions where in the pond?

Answer 10

near the surface

Question 11

anytime you get sulfic oxide and nitric oxide in the presents of water what does it form?

Answer 11

acid rain! HNO3, H2SO4

Question 12

you can predict how much SOx and NOx will be dissolved through what law?

Answer 12

henrys law

Question 13

what is an important example of colloidal particles in water and why?

Answer 13

clays due to their cation exchange properties

Question 14

what are the important features of colloids?

Answer 14

1. ability to adsorb molecules or ions from the surrounding solution
2. adsorption may be reversible or irreversible
3. different purposes may decrease solutes or faciliate movement of solutes

Question 15

where in the clay is where cation exchange occurs and why?

Answer 15

at the aluminum site because of the negative charge.

Question 16

what are the 3 types of colloids:

Answer 16

1. hydrophlic
2. hydrophobic
3. association colloids

Question 17

colloidal stability is affected by what two things?

Answer 17

1. hydration

2. surface charge effects

Question 18

if pH system > pHo of colloids what does this means for the charge?

Answer 18

-ve charge

Question 19

if pH system

Answer 19

+ve charge

Question 20

what is the thickness of the electrical double layer?

Answer 20

1/e=0.37

Question 21

clays have high adsorption capacity for what?

Answer 21

organics, water and cations

Question 22

Humic acid:

Answer 22

is more hydrophobic and higher molecular weight

Question 23

Fulvic acid:

Answer 23

more hydrophilic and smaller molecular weight

Question 24

Qe:

Answer 24

is basically concentration in solid phase

Question 25

Ce:

Answer 25

is concentration in water phase

Question 26

Kd= with Qe and Ce

Answer 26

Qe/Ce

Question 27

what is the xetopotential:

Answer 27

is a measure of surface charge