Analytical Chemistry Lecture Review Flashcards

Vocabulary flashcards covering key analytical chemistry terminology, sampling strategies, gravimetric and volumetric concepts, and chemical concentration units based on lecture notes.

Homogeneous Material

A material whose composition is the same everywhere.

Heterogeneous Material

A material whose composition differs from place to place.

Interference

A species other than the analyte that increases or decreases the response of the analytical method, making it appear that there is more or less analyte than is actually present.

Masking

The transformation of an interfering species into a form that is not detected by the analytical method.

Qualitative Analysis

An analysis performed to identify what constituent species are present in an unknown sample.

Quantitative Analysis

An analysis performed to determine how much of a constituent species is present in an unknown sample.

Calibration Curve

A graph showing detector response as a function of analyte concentration or quantity.

Tare

The mass of an empty receiving vessel placed on a balance pan.

Sensitivity (Analytical Balance)

The smallest increment of mass that can be measured by a balance.

Buoyancy

The upward force exerted on an object in a liquid or gaseous fluid.

True Mass

The actual mass of an object measured in a vacuum.

Buoyancy Equation

The equation used to convert apparent mass $m'$ weighed in air to true mass $m$ in vacuum: $m = \frac{m'\left(1 - \frac{d_a}{d_w}\right)}{\left(1 - \frac{d_a}{d}\right)}$, where $d_a$ is air density ($0.0012\,g/mL$), $d_w$ is calibration weight density ($8.0\,g/mL$), and $d$ is object density.

Parallax

The measurement error that occurs when an observer's eye is not at the exact same height as the liquid level or meniscus being read.

Adsorption

The process in which a substance sticks to the surface of a solid or liquid.

Absorption

The process in which a substance is taken inside another material, such as water taken into a sponge.

Mother Liquor

The liquid from which a substance precipitates or crystallizes during a reaction or purification.

Filtrate

The liquid that passes through a filter paper or porous filter disk.

Ignition

The process of heating a precipitate at high temperatures over a burner or in a furnace to convert it into a pure substance of known, constant composition.

Slurry

A mixture containing a solid suspended in a liquid.

Calibration

The process of measuring the actual quantity of mass, volume, force, or electric current corresponding to an indicated scale quantity on an instrument.

Robert Boyle

The scientist (1627–1691) who coined the term "analyst" in his 1661 book The Sceptical Chymist.

Antoine Lavoisier

The scientist (1743–1794) known as the "father of analytical chemistry" who utilized precision balances for quantitative experiments on the conservation of mass.

Izaak Maurits Kolthoff

The chemist (1894–1993) described as the father of modern analytical chemistry for transforming how scientists separate, identify, and quantify chemical substances.

Analyte

The specific constituent of interest in a sample that is sought during chemical analysis.

Matrix

All constituents in a sample combined, excluding the target analyte.

Technique

A fundamental chemical or physical principle that can be used to analyze a sample, such as Atomic Absorption Spectroscopy.

Method

A specific application of a technique to analyze a particular analyte in a specific matrix.

Procedure

A set of detailed written directions for applying an analytical method to a specific sample.

Protocol

A set of strict written guidelines for sample analysis specified by an administrative agency, commonly used to support public policy.

Gross Sample

A representative sample consisting of several combined portions of the bulk material to be tested.

Laboratory Sample

A reduced portion of the gross sample that is actually delivered to and analyzed in the laboratory.

Aliquot

A precisely measured fractional portion of the volume of a liquid sample taken for analysis.

Selective Sample

A sample deliberately chosen using a sampling scheme that screens out or isolates materials with specific characteristics, often used when contamination is suspected.

Composite Sample

A sample consisting of two or more combined portions collected at the same time to represent the overall material being investigated.

Representative Sample

A sample that accurately reflects the chemical and physical characteristics of the parent material.

Random Sample

A sample selected in such a manner that every individual portion of the parent material has an equal and known chance of being selected.

Sample Preparation

The series of steps required to convert a representative laboratory sample into a suitable state for analytical measurement.

Molarity (M)

A concentration unit defined as the number of moles of solute per liter of solution: $\text{Molarity (M)} = \frac{\text{moles of solute}}{\text{liter of solution}}$.

Molality (m)

A concentration unit defined as the number of moles of solute per kilogram of solvent: $\text{Molality (m)} = \frac{\text{moles of solute}}{\text{kilograms of solvent}}$.

Normality (N)

A concentration unit defined as the number of equivalents of solute per liter of solution: $\text{Normality (N)} = \frac{\text{moles of solute} \times f}{\text{liter of solution}}$, where $f$ is the equivalence factor.

Solute and Solvent Phase Combinations

The classification of solutions into combinations of gas, liquid, or solid solutes dissolved in gas, liquid, or solid solvents.

Tolerance Limits for Laboratory Weights

The maximum permissible deviation in mass specified for standard laboratory balance calibration weights (Class 1 and Class 2).

Equivalence Factor (f)

The factor representing the number of reacting units per mole of substance, used to convert molarity to normality: $f = 1$ for $HCl$ and $NaOH$, $f = 3$ for $H_3PO_4$, $f = 6\,\text{equiv/mol}$ for $Ca_3(PO_4)_2$, and $f = 2$ for $BaCl_2$.