Chapter 27

Question 1

Occurs when a substance is taken up inside another

Answer 1

Absorption

Question 2

Occurs when a substance becomes attached to the surface of another substance

Answer 2

Adsorption

Question 3

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

Answer 3

Colloid

Question 4

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

Answer 4

Combustion analysis

Question 5

Occurs when a substance whose solubility is not exceeded precipitates along with one whose solubility is exceeded

Answer 5

Coprecipitation

Question 6

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

Answer 6

Dialysis

Question 7

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

Answer 7

Digestion

Question 8

Region comprising the charged surface of an electrode or a particle plus the oppositely charged region of solution adjacent to the surface

Answer 8

Electric double layer (double layer)

Question 9

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

Answer 9

End point

Question 10

Point in a titration at which the quantity of titrant is exactly sufficient for stoichiometric reaction with the analyte

Answer 10

Equivalence point

Question 11

A prices in which a trace constituent of a solution is intentionally coprecipitated with a major constituent

Answer 11

Gathering

Question 12

Any analytical method that relies on measuring the mass of a substance (such as a precipitate) to complete the analysis

Answer 12

Gravimetric analysis

Question 13

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

Answer 13

Homogeneous precipitation

Question 14

One that readily picks up water from the atmosphere

Answer 14

Hygroscopic substance

Question 15

The heating to high temperature of some gravimetric precipitates to convert them into a known, constant composition that can be weighed

Answer 15

Ignition

Question 16

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

Answer 16

Masking agent

Question 17

Process whereby molecules in solution come together randomly to form small crystalline aggregates that can grow into larger crystals

Answer 17

Nucleation

Question 18

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

Answer 18

Peptization

Question 19

A substance that precipitates a species from solution

Answer 19

Precipitant

Question 20

One in which the analyte forms a precipitate with the titrant

Answer 20

Precipitation titration

Question 21

Thermal decomposition of a substance

Answer 21

Prolysis

Question 22

One that contains more dissolved solute than would be present at equilibrium

Answer 22

Supersaturated solution

Question 23

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

Answer 23

Thermogravimetric analysis

Question 24

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)

Answer 24

Titration curve