SSC 200 EXAM 3 QUIZ QUESTIONS & 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
False - Answer -True
As biotite weathers in soils, which of the following would not likely develop by mere
alteration of this mineral?
Select one:
A. smectite
B. fine-grained mica
C. chlorite
D. kaolinite
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
False - Answer -True
As biotite weathers in soils, which of the following would not likely develop by mere
alteration of this mineral?
Select one:
A. smectite
B. fine-grained mica
C. chlorite
D. kaolinite
