ENSC 3134 Exam 3 – Questions Answered With Expert
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Inner-Sphere Complexes
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1 Colloid 2 Sources of Charge in Soil
Inner Vs Outer Sphere Complexes - what
3 4 Isomorphic Substitution
does the bottom blank represent?
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Terms in this set (145)
A colloid is a substance microscopically dispersed throughout
Colloid
another substance.
Sources of Soil Colloids Derived from minerals (clay) and organic matter.
Crystalline silicate clays, Noncrystalline silicate clays, Iron and
Major Types of Soil Colloids
aluminum oxides, Organic (humus) colloids.
Tetrahedra: Silicon surrounded by oxygen; Octahedra: Aluminum
Basic Crystal Structure or magnesium surrounded by oxygen/hydroxyl; Sheets and
Layers: Arrangement of tetrahedral and octahedral sheets.
The replacement of one ion for another in a crystal structure
Isomorphic Substitution without changing the structure itself, leading to charge
imbalance.
1:1 Clays Kaolinite - non-expanding.
, 2:1 Expanding Clays Montmorillonite - high shrink-swell capacity.
2:1 Semi-Expanding Clays Vermiculite.
2:1 Non-Expanding Clays Illite - potassium prevents expansion.
Present in highly weathered soils, responsible for red/yellow soil
Iron and Aluminum Oxides
colors.
Basic Structure of Organic Complex molecules rich in carbon.
Matter
Functional Units of Organic Carboxyl, phenolic, and hydroxyl groups contribute to CEC.
Matter
Isomorphic Substitution: Permanent charge from clay minerals;
Sources of Charge in Soil pH Dependent Charge: Functional groups on organic matter,
broken edges of clays, and oxides.
Cation Exchange Exchange of cations between soil colloids and soil solution.
Cation Exchange Capacity Total capacity of a soil to hold exchangeable cations.
(CEC)
Texture (more clay = higher CEC), Colloid Type (humus >
Factors Affecting CEC
montmorillonite > kaolinite), pH (higher pH = higher CEC).
General Characteristics of CEC Varies with soil composition, texture, and organic matter content.
Stoichiometry of Charge Charge balance must be maintained.
Cation Preference Higher charge and smaller hydrated radius = stronger attraction.
Measuring & Calculating CEC Sum of exchangeable cations per unit soil weight.
Percentage of CEC occupied by base cations (Ca²⁺, Mg²⁺, K⁺,
Base Saturation
Na⁺).
Calculation of Base Saturation (Sum of base cations / Total CEC) × 100.
Exchangeable Acidity Acid Cations: H⁺ and Al³⁺.
Less significant than CEC, occurs mainly in highly weathered
Anion Exchange Capacity (AEC)
soils.
Influence on AEC Influenced by soil pH and mineralogy.
Organic matter addition increases CEC; Liming increases CEC by
Manipulating CEC and Fertility
raising pH; Clay mineral type affects nutrient retention.
Cation Exchange Capacity, a measure of the soil's ability to hold
CEC
cations.
Organic matter addition Increases CEC.
Liming Increases CEC by raising pH.
Clay mineral type Affects nutrient retention.
Acidity Presence of H⁺ ions in the soil.
Alkalinity Presence of OH⁻ ions in the soil.
pH Logarithmic measure of H⁺ concentration.
Microbial respiration Releases CO₂ which forms carbonic acid.
Decomposition of organic Produces organic acids.
matter
Carbonic Acids Formed by the reaction CO₂ + H₂O → H₂CO₃.
Aluminum Hydrolysis Al³⁺ hydrolyzes water, releasing H⁺.
Carbonates CaCO₃ and MgCO₃ neutralize acidity.
Weathering Leaching of base cations decreases alkalinity.
Base-Producing Anions Hydroxides and carbonates contribute to alkalinity.
Basic Soils Dominated by base cations (Ca²⁺, Mg²⁺, K⁺, Na⁺).
Acid Soils Dominated by acid cations (H⁺, Al³⁺).
Insight
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INBDE Orthodontics NBDE II Review - Prosthodontics Perio Study
201 terms 69 terms Teacher 78 terms
dong_lee82 Preview melissa_jarvis7 Preview Hunter_Charters
Practice questions for this set
Learn 1 /7 Study with Learn
Inner-Sphere Complexes
Choose an answer
1 Colloid 2 Sources of Charge in Soil
Inner Vs Outer Sphere Complexes - what
3 4 Isomorphic Substitution
does the bottom blank represent?
Don't know?
Terms in this set (145)
A colloid is a substance microscopically dispersed throughout
Colloid
another substance.
Sources of Soil Colloids Derived from minerals (clay) and organic matter.
Crystalline silicate clays, Noncrystalline silicate clays, Iron and
Major Types of Soil Colloids
aluminum oxides, Organic (humus) colloids.
Tetrahedra: Silicon surrounded by oxygen; Octahedra: Aluminum
Basic Crystal Structure or magnesium surrounded by oxygen/hydroxyl; Sheets and
Layers: Arrangement of tetrahedral and octahedral sheets.
The replacement of one ion for another in a crystal structure
Isomorphic Substitution without changing the structure itself, leading to charge
imbalance.
1:1 Clays Kaolinite - non-expanding.
, 2:1 Expanding Clays Montmorillonite - high shrink-swell capacity.
2:1 Semi-Expanding Clays Vermiculite.
2:1 Non-Expanding Clays Illite - potassium prevents expansion.
Present in highly weathered soils, responsible for red/yellow soil
Iron and Aluminum Oxides
colors.
Basic Structure of Organic Complex molecules rich in carbon.
Matter
Functional Units of Organic Carboxyl, phenolic, and hydroxyl groups contribute to CEC.
Matter
Isomorphic Substitution: Permanent charge from clay minerals;
Sources of Charge in Soil pH Dependent Charge: Functional groups on organic matter,
broken edges of clays, and oxides.
Cation Exchange Exchange of cations between soil colloids and soil solution.
Cation Exchange Capacity Total capacity of a soil to hold exchangeable cations.
(CEC)
Texture (more clay = higher CEC), Colloid Type (humus >
Factors Affecting CEC
montmorillonite > kaolinite), pH (higher pH = higher CEC).
General Characteristics of CEC Varies with soil composition, texture, and organic matter content.
Stoichiometry of Charge Charge balance must be maintained.
Cation Preference Higher charge and smaller hydrated radius = stronger attraction.
Measuring & Calculating CEC Sum of exchangeable cations per unit soil weight.
Percentage of CEC occupied by base cations (Ca²⁺, Mg²⁺, K⁺,
Base Saturation
Na⁺).
Calculation of Base Saturation (Sum of base cations / Total CEC) × 100.
Exchangeable Acidity Acid Cations: H⁺ and Al³⁺.
Less significant than CEC, occurs mainly in highly weathered
Anion Exchange Capacity (AEC)
soils.
Influence on AEC Influenced by soil pH and mineralogy.
Organic matter addition increases CEC; Liming increases CEC by
Manipulating CEC and Fertility
raising pH; Clay mineral type affects nutrient retention.
Cation Exchange Capacity, a measure of the soil's ability to hold
CEC
cations.
Organic matter addition Increases CEC.
Liming Increases CEC by raising pH.
Clay mineral type Affects nutrient retention.
Acidity Presence of H⁺ ions in the soil.
Alkalinity Presence of OH⁻ ions in the soil.
pH Logarithmic measure of H⁺ concentration.
Microbial respiration Releases CO₂ which forms carbonic acid.
Decomposition of organic Produces organic acids.
matter
Carbonic Acids Formed by the reaction CO₂ + H₂O → H₂CO₃.
Aluminum Hydrolysis Al³⁺ hydrolyzes water, releasing H⁺.
Carbonates CaCO₃ and MgCO₃ neutralize acidity.
Weathering Leaching of base cations decreases alkalinity.
Base-Producing Anions Hydroxides and carbonates contribute to alkalinity.
Basic Soils Dominated by base cations (Ca²⁺, Mg²⁺, K⁺, Na⁺).
Acid Soils Dominated by acid cations (H⁺, Al³⁺).
