SOIL 2124 EXAM 3 QUESTIONS AND CORRECT ANSWERS!!!!
ALREADY GRADED A+
mineral or organic particles in soil having a diameter less than 1um (0.000001 m)- CLAY SIZE RANGE -
(ANSWER)Soil Colloid
Three types of clays - (ANSWER)Iron and aluminum oxide
non-crystalline silicate clays
crystalline and silicate clays
found in humid tropical climates, highly weathered, ultisols and oxisols
-some may have crystalline structure while others are amorphous - (ANSWER)Iron and Aluminum Oxides
tightly bonded silicon, aluminum and oxygen NO ORDERED ARRANGEMENT
-volcanic ash, Andisols - (ANSWER)Non-crystalline Silicate Clays
DOMINANT IN MOST SOILS
-specific crystal structure - (ANSWER)Crystalline Silicate Clay
2 basic structural units of structured clays - (ANSWER)Si Tetrahedron
Al Octahedron
what makes a Sheet - (ANSWER)a series of structural units that are bonded together
what makes a Layer and two types - (ANSWER)Adjacent sheets that are bonded together
-1:1 (Si:Al), tetra:octa SiAl/SiAl
-2:1 (Si:Al), tetra:octa SiAlSi/SiAlSi
what makes a clay particle - (ANSWER)a series of layers
,SOIL 2124 EXAM 3 QUESTIONS AND CORRECT ANSWERS!!!!
ALREADY GRADED A+
Where does permanent charge of clays come from? 1:1 or 2:1? - (ANSWER)isomorphous substitution:
the replacement of one atom by another of similar size in the crystal structure
2:1 clays
What is variable charge? 1:1 or 2:1? - (ANSWER)pH dependent charge
all except 2:1...1:1 clays, non crystall, silicate in Fe, Al oxides
-organic mater
-edges of clay (Si-OH)
What is the central atom in Tetrahedron and what is it replaced by? does it become more negative or
positive? - (ANSWER)Si4+
replaced by Al3+
becomes more negative
What is the central atom in Octahedron and what is it replaced by? more negative or pos? -
(ANSWER)Al3+
replaced by Mg2+
becomes more negative
1:1 silicates - (ANSWER)Kaolinite is most common
-halloysite, nacrite, and dickite
2:1 silicates - (ANSWER)Illite, Chlorite, Vermiculite, Montorillonite
3 types if 2:1 silicates - (ANSWER)2:1 non expanding
2:1:1 chlorite
2:1 expanding
, SOIL 2124 EXAM 3 QUESTIONS AND CORRECT ANSWERS!!!!
ALREADY GRADED A+
Kaolinite - (ANSWER)1:1
non-expanding
interlayer hydrogen bond (superglue)
large
NO ISOMORPH SUB, NO PERM CHARGE, surface charge is low
OCT-TET/H+/OCT-TET
Illite - (ANSWER)2:1
non-expanding
three sheets per layer
interlater POTASSIUM K+, regular glue
ISOMORPH SUB
higher surface charge than kaolinite
TET-OCT-TET/K+/TET-OCT-TET
Chlorite - (ANSWER)2:1
non-expanding
three sheets per later
Interlayer Mg OXIDE
ISOMORPH SUB
high surface charge
TET-OCT-TET/Mg+/TET-OCT-TET
Vermiculite - (ANSWER)2:1
expanding
interlayer VARIOUS CATIONS (pos)
high surface area
ALREADY GRADED A+
mineral or organic particles in soil having a diameter less than 1um (0.000001 m)- CLAY SIZE RANGE -
(ANSWER)Soil Colloid
Three types of clays - (ANSWER)Iron and aluminum oxide
non-crystalline silicate clays
crystalline and silicate clays
found in humid tropical climates, highly weathered, ultisols and oxisols
-some may have crystalline structure while others are amorphous - (ANSWER)Iron and Aluminum Oxides
tightly bonded silicon, aluminum and oxygen NO ORDERED ARRANGEMENT
-volcanic ash, Andisols - (ANSWER)Non-crystalline Silicate Clays
DOMINANT IN MOST SOILS
-specific crystal structure - (ANSWER)Crystalline Silicate Clay
2 basic structural units of structured clays - (ANSWER)Si Tetrahedron
Al Octahedron
what makes a Sheet - (ANSWER)a series of structural units that are bonded together
what makes a Layer and two types - (ANSWER)Adjacent sheets that are bonded together
-1:1 (Si:Al), tetra:octa SiAl/SiAl
-2:1 (Si:Al), tetra:octa SiAlSi/SiAlSi
what makes a clay particle - (ANSWER)a series of layers
,SOIL 2124 EXAM 3 QUESTIONS AND CORRECT ANSWERS!!!!
ALREADY GRADED A+
Where does permanent charge of clays come from? 1:1 or 2:1? - (ANSWER)isomorphous substitution:
the replacement of one atom by another of similar size in the crystal structure
2:1 clays
What is variable charge? 1:1 or 2:1? - (ANSWER)pH dependent charge
all except 2:1...1:1 clays, non crystall, silicate in Fe, Al oxides
-organic mater
-edges of clay (Si-OH)
What is the central atom in Tetrahedron and what is it replaced by? does it become more negative or
positive? - (ANSWER)Si4+
replaced by Al3+
becomes more negative
What is the central atom in Octahedron and what is it replaced by? more negative or pos? -
(ANSWER)Al3+
replaced by Mg2+
becomes more negative
1:1 silicates - (ANSWER)Kaolinite is most common
-halloysite, nacrite, and dickite
2:1 silicates - (ANSWER)Illite, Chlorite, Vermiculite, Montorillonite
3 types if 2:1 silicates - (ANSWER)2:1 non expanding
2:1:1 chlorite
2:1 expanding
, SOIL 2124 EXAM 3 QUESTIONS AND CORRECT ANSWERS!!!!
ALREADY GRADED A+
Kaolinite - (ANSWER)1:1
non-expanding
interlayer hydrogen bond (superglue)
large
NO ISOMORPH SUB, NO PERM CHARGE, surface charge is low
OCT-TET/H+/OCT-TET
Illite - (ANSWER)2:1
non-expanding
three sheets per layer
interlater POTASSIUM K+, regular glue
ISOMORPH SUB
higher surface charge than kaolinite
TET-OCT-TET/K+/TET-OCT-TET
Chlorite - (ANSWER)2:1
non-expanding
three sheets per later
Interlayer Mg OXIDE
ISOMORPH SUB
high surface charge
TET-OCT-TET/Mg+/TET-OCT-TET
Vermiculite - (ANSWER)2:1
expanding
interlayer VARIOUS CATIONS (pos)
high surface area
