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27 Cards in this Set
- Front
- Back
What are Gravimetric Methods? |
Quantitative methods that are based on determining the mass of a pure compound to which the analyte is chemically related. |
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What's a colloid? |
solids particles that are less than 10^-4 cm in diameter |
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What's a supersaturated solution? |
An unstable solution that contains a higher solute concentration than saturated solution. |
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What is nucleation? |
a process in which minimum amount of atoms, particles and molecules join together to make a stable solid |
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What is Particle Growth? |
When multiple particles collide with each other and they grow and become bigger |
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What's adsorption? |
a process which a substance is held on the surface of a solid |
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What's absorption? |
The retention of a substance within the pores of a solid |
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Why is a colliodial precipitate not desired? |
It's difficult to filter |
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What's digestion? |
A process in which a precipitate is heated in the solution from which it was formed (the mother liquor) and allowed to stand in contact with the solution. |
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What does digestion improve? |
The purity and filterability of colloidal and crystalline precipitates |
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What are the four types of co-precipitation? |
Surface absorption, mixed-crystal formation, occulsion, and mechanical entrapment |
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What's co-precipitation? |
a process which a normally soluble compounds are carried out by a precipitate |
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What's a mother liquor? |
the solution in which a precipitate was formed |
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What's mixed crystal formation? |
a type of co-precipitation in which a contaminant ion replaces an ion in the lattice of a crystal |
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What's occlusion? |
A type of co-precipitate in which a compound is trapped within a pocket formed during pocket growth |
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When does mechanical entrapment occur? |
When crystals lie close together during growth. Several crystals grow together and in so doing trap a portion of the solution in a tiny pocket. |
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What's a primary standard? |
An ultrapure compound that serves as a reference material for titration or another type of qualitative analysis |
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What's a secondary standard? |
A compound whose purity has been determined by chemical analysis. |
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What does a secondary standard serve as? |
The working standard for material for titrations and for many analysis |
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What is standardization? |
Where the concentration of a volumetric solution has been determined titrating it against a carefully measured quantity of a primary or secondary standard or an exactly known volume of another standard solution. |
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What's a back titration? |
a process where the excess of a standard solution is used to consume an analyte is determined by titration of a second standard solution |
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What's a titration curve? |
Plots of concentration related variable against a titrant volume |
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What's a millimole? |
1000th of a mole, often used in titration calculations for its small number being easier to work with |
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What's a stochiometric ratio? |
The ratio of which a chemical in a chemical equation is balanced with (I.e. 1:1, 1:2, 1:5) |
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What's precipitation? |
the process of which a solid phase forms and is carried out in a solution when the solubility product of a chemical is exceeded |
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What's agglomerate mean? |
to collect in a mass or a group (Ex. The colloid agglomerate) |
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What's a chelating agent? |
An organic compound that contains two or more electron donor groups located in such a configuration that five- or six-membered rings are formed when the donor groups complex a cation. |