Chapter 10

Question 1

Henry’s Law

Answer 1

C=KP

Question 2

Solubility of gases ________ as temperature increases

Answer 2

decreases

Question 3

COD

Answer 3

chemical oxygen demand
- measured by using dichromate as an oxidizing titrant to measure the demand of oxygen in water

Question 4

Using COD to measure oxygen demand is inaccurate due to the fact that ___________________

Answer 4

Acidified dichromate is so strong of an oxidizing agent that is oxidizes substances that are very slow to consume oxygen in natural water

Question 5

BOD

Answer 5

biological oxygen demand
- the capacity of the organic and biological matter of natural water to consume oxygen
- uses bacteria and measures oxygen present before and after a period of time

Question 6

TOC

Answer 6

total organic carbon
- dissolved and suspended organic matter

Question 7

DOC

Answer 7

dissolved organic carbon
- about 5 ppm in surface waters (bogs/swamps can be 10x this)

Question 8

fermentation

Answer 8

anaerobic reaction done by bacteria to decompose organic matter
- both oxidation and reduction occurs

Question 9

epilimnion

Answer 9

top layer of a stratified lake
- substances exist in their most oxidized forms

Question 10

hypolimnion

Answer 10

bottom layer of a stratified lake
- substances exist in their most reduced forms

Question 11

Acid-mine drainage

Answer 11

soluble Fe2+ is oxidized when surfaced during mining and is converted into insoluble Fe3+
- reacts with sulfide to form iron(III)sulfide
- and sulfuric ACID

Question 12

Low pE values signify _____ electron availability, so the medium is very reducing/oxidizing in nature

Answer 12

high, reducing

Question 13

High pE values signify ______ electron availability, to the medium is very reducing/oxidizing in nature

Answer 13

low, oxidizing

Question 14

Nernst Equation

Answer 14

E = E* - (RT/zF)lnQ

pE = E/0.0591 (for 1e- @25*C)

Question 15

calcareous waters

Answer 15

natural waters exposed to limestone
- dissolve carbonate ions into water

Question 16

Ksp

Answer 16

solubility product equilibrium constant
- concentration of product ions, raised to its coeffiecient in a balanced equation

Question 17

most abundant ions in calcareous water

Answer 17

Ca2+ and H2CO3 (bicarbonate)

Question 18

source of bicarbonate in noncalcareous waters?

Answer 18

aluminosilicates

Question 19

Lower line (rxn) of water pourbaix diagram

Answer 19

2H2O + 2e- = H2 + OH-

Question 20

Upper line (rxn) of water pourbaix diagram

Answer 20

O2 + 4H+ + 4e- = 2H2O