SSC 200 Exam 3 Quiz Questions With Correct Answers

SSC 200 Exam 3 Quiz Questions With
Correct Answers

For most soil colloids, electronegative charges predominate although 2:1
silicate clays have a net electropositive charge in very acidic soils.
Select one:
True
False - ANSWER False

The exchange complexes of strongly acid (pH 4.5) mineral soils are saturated
mainly with ________.
Select one:
A. tightly bound Al3+ ions
B. exchangeable Al3+ ions
C. exchangeable Al(OH2)+ ions
D. exchangeable H+ ions
E. tightly bound H+ ions - ANSWER exchangeable Al3+ ions

Which of the silicate clays would likely have the highest level of potassium in the
crystal structure?
Select one:
A. vermiculite
B. fine-grained mica
C. chlorite
D. smectite
E. kaolinite - ANSWER fine-grained mica

The acidity of "acid rain" can be partially traced to the reaction of CO2 in the
atmosphere forming carbonic acid (H2CO3).
Select one:
True
False - ANSWER True

Anion exchange by formation of outer sphere complexes is of least importance
in the plant absorption of ________.
Select one:
A. MoO4-2
B. Cl-
C. SO42-
D. NO3-

, E. H2PO4-. - ANSWER H2PO4-.

For most soil colloids, electronegative charges predominate, although aluminum
and iron oxides can have a net electropositive charge under very acidic soil
conditions.
Select one:
True
False - ANSWER True

An alkaline soil contains 20% clay and 3% humus. If the pure clay has a CEC of
40 cmolc/kg and the humus 200 cmolc/kg, calculate the CEC/kg of the soil.
Select one:
A. 12
B. 8
C. 30
D. 16
E. 14 - ANSWER 14

The electronegative charge on 2:1 type silicate clays is due primarily to
________.
Select one:
A. the effect of pH on the presence of H+ ions in the exchange complex
B. the preponderance of tetrahedral sheets compared to octahedral sheets
C. ionization of surface OH groups
D. extremely small size of the individual colloid particles
E. substitution of one metallic atom for another in the crystal structure of the
clay - ANSWER Substitution of one metallic atom for another in the crystal
structure of the clay

Humus has a much higher cation adsorption capacity than clay.
Select one:
True
False - ANSWER True

Which of the following is not a characteristic of soil colloids?
Select one:
A. very small size
B. ability to exchange ions with the soil solution
C. electronegative charges
D. low water holding capacity
E. high external surfaces - ANSWER low water holding capacity

Soil chemistry can affect dispersion, which is a soil physical condition where
each soil particle behaves as an individual and aggregates do not form.
Select one:
True