Chapter 27 Flashcards
Occurs when a substance is taken up inside another
Absorption
Occurs when a substance becomes attached to the surface of another substance
Adsorption
A dissolved particle with a diameter in the approximate range 1-500 nm. It is too large to be considered one molecule but too small to simply precipitate
Colloid
A technique in which a sample is heated in an atmosphere of O2 to oxidize it to CO2 and H2O, which are collected and weighed or measured by gas chromatography. Modifications permit the simultaneous analysis of N, S, and halogens
Combustion analysis
Occurs when a substance whose solubility is not exceeded precipitates along with one whose solubility is exceeded
Coprecipitation
A technique in which solutions are placed on either side of a semipermeable membrane that allows small molecules, but not large molecules, to cross. Small molecules in the two solutions diffuse across and equilibriate between the two sides. Large molecules are retained on their original side
Dialysis
Process in which a precipitate is left (usually warm) in the presence of mother liquor to promote particle recrystallization and growth. Purer, more easily filterable crystals result. Also used to describe any chemical treatment in which a substance is decomposed to transform the analyte into a form suitable for analysis
Digestion
Region comprising the charged surface of an electrode or a particle plus the oppositely charged region of solution adjacent to the surface
Electric double layer (double layer)
Point in a titration at which there is a sudden change in a physical property, such as indicator color, pH, conductivity, or absorbance; used as a measure of the equivalence point
End point
Point in a titration at which the quantity of titrant is exactly sufficient for stoichiometric reaction with the analyte
Equivalence point
A prices in which a trace constituent of a solution is intentionally coprecipitated with a major constituent
Gathering
Any analytical method that relies on measuring the mass of a substance (such as a precipitate) to complete the analysis
Gravimetric analysis
A technique in which a precipitating agent is generated slowly by a reaction in homogeneous solution, effecting a slow crystallization instead of a rapid precipitation of product
Homogeneous precipitation
One that readily picks up water from the atmosphere
Hygroscopic substance
The heating to high temperature of some gravimetric precipitates to convert them into a known, constant composition that can be weighed
Ignition
A reagent that selectively reacts with one (or more) component(a) of a solution to prevent the component(s) from interfering in a chemical analysis
Masking agent
Process whereby molecules in solution come together randomly to form small crystalline aggregates that can grow into larger crystals
Nucleation
Occurs when washing some ionic precipitates with distilled water causes the ions that neutralize the charges of individual particles to be washed away. The particles then repel one another, disintegrate, and pass through the filter with the wash liquid
Peptization
A substance that precipitates a species from solution
Precipitant
One in which the analyte forms a precipitate with the titrant
Precipitation titration
Thermal decomposition of a substance
Prolysis
One that contains more dissolved solute than would be present at equilibrium
Supersaturated solution
A technique in which the mass of a substance is measured as the substance is heated. Changes in mass indicate decomposition of the substance, often to well-defined products
Thermogravimetric analysis
A graph showing how the concentration of a reactant or a physical property of the solution varies as one reactant (the titrant) is added to another (the analyte)
Titration curve
