ECS - Exam 2 2025 With Correct Answers

ECS - Exam 2 2025 With Correct
Answers




Sorption - correct answer The retention of a species without the implications to its retention mechanism
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Adsorption - correct answer The binding of an ion or small molecule to a surface at an isolated site (2d-surface
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complex). Not including surface precipitation and/or polymerization. One of the most important chemical
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processes in soils - nutrients, metals, pesticides, and other organic chemicals retained on soil surfaces; affects
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transport of nutrients and contaminants in soils
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Absorption - correct answer The uptake of a species WITHIN another material
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Surface Precipitation - correct answer A 3D growth mechanism of a species on a surface. This mechanism
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differs from Adsorb. in that the retained species directly interacts with each other on the surface and can eve
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have the solid structure grow away from the original substrate
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Precipitation - correct answer The formation of a 3D structure without the association of a substrate (sorbent)
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material



Sorptive - correct answer A species in solution that may undergo sorption
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Sorbate - correct answer A species retain on another material
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, Sorbent - correct answer The substrate material responsible for the retention of a solution species
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Fate of Pesticides - correct answer Drift, photodecomposition, runoff, volatilization, absorption, soil
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decomposition - adsorption, residues, leaching o o o o




Inorganic Surface Function Groups - correct answer Oxygen atoms of the silica tetrahedral layer (siloxane
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surface) in the interlayer region of phyllosilicates. OH groups associate with edges of minerals
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Surface Functional Groups - correct answer Hydroxyl, Carbonyl (organic), Carboxyl (organic), and Amino
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Group. Phenolic - consists of phenyl and hydroxyl groups (organic)
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Forces involved in Adsorption - correct answer Physical (distance and valence) - Van der waals (weak
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electrostatic forces) and Electrostatic complexes (ion exchange)
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Chemical (electron reconfiguration, breaking/making bonds)- Inner-sphere and outer-sphere complexation
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Surface Complex - correct answer Surface Function Group + ion or molecule in solution = stable molecular
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entity, called SURFACE COMPLEX
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Surface Complexes - correct answer Outer-sphere - water molecule is present between the SFG and bound
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(adsorbed) ion or molecule. o o o o




Inner-sphere complex - no water molecule present between the SFG and bound ion or molecule
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Inner and outer-sphere complexation occurs simultaneously (not mutually exclusive)
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Inner-sphere Complex - correct answer Strong (covalent and ionic bonding), May be slower than outer sphere
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complexation, Often irreversible or "fixed" depending upon environmental conditions, weakly affected by
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solution ionic strength, surface charge can be changed by complexation, charged surface is not required for
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complexation