Lab 2 Paper Chromatography
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Rf values depends upon concentration of components present? T/F
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False
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When Mary did her pre-lab, she measured D and L in inches. Sam made his measurements in cm. Will they get different answers?
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No
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What is the term for a widely used resolution technique which depends on solubility differences?
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Chromatography
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When the solvent rises up the chromatography paper, what is that process called?
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Applied/gravitational pressure and capillary effect
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What are the Rf values?
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the qualities of the position of the spots from the chromatography.
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Why can samples often be separated into their components by chromatography
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the attraction they have at different phases of moving by the absorption of the solvent
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The solvent moves 3 cm in about 10 minutes. Why shouldn't the experiment be stopped at the time instead of waiting 75 minutes for the solvent to move 10 cm?
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The solvent needs enough time to move through the chromatograph to allow enough separation to identify the components
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The components of a mixture are absorbed on the solid to varying degrees
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nature of component, nature of absorbent, and the temperature
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in a chromatographic experiment, a mixture is deposited on some solid absorbing substance
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filter paper, thin layer of silica gel, charcoal, or glass beads
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as the solvent passes the deposited sample, the various components tend to
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be dissolved and swept along the solid
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the rate at which a component will move along the solid depends on
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its relative tendency to be dissolved in the solvent and absorbed on the solid
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net effect
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as the solvent passes slowly through the solid, the components separate from each other and move along as rather diffuse zones
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names of chromatography
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column, thin layer, paper, and vapor
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paper chromatography
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separate a mixture of metallic ions in solution
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because the ions differ in properties
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they move at different rates
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staining reagent used
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to differ the ions
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Rf value
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D (distance component moves) / L (distance solvent moves)
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solutions used
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silver nitrate, copper II nitrate, cobalt II nitrate, iron III nitrate, and mercury II nitrate
