Analytical Chemistry, Cheat Sheet of Chemistry

Download Analytical Chemistry and more Cheat Sheet Chemistry in PDF only on Docsity! Accuracy: A measure of the agreement between an analytical result and the true or accepted value for the measured quantity. Autocatalysis: A condition in which the product of a reaction catalyzes the reaction itself. Back-titration: process in which the excess of a standard solution used to consume an analyte is determined by titration with a second standard. Beer's Law: The fundamental relationship for the absorption of radiation by matter, that is, A= abc, where a is the absorptivity, b is the path length of the beam of radiation and c is the concentration of the absorbing species Colloidal suspension: precipitation with tiny particles (<10^-4 cm) almost invisible to the eye detectable by shining a light trough it. Confidance interval: Defines bounds about the experimental mean within which the true mean should be located. Coprecipitation: The carrying down of otherwise soluble species either within a solid or on the surface of a solid as it precipitates Crystalline suspension: Particles with greater than colloidal dimensions temporarily disepersed in a liquid. Electrode of the 1st kind: A metalic electrode whose potential is proportional to the logarith of the concentration of a cation derived from the electrode metal. Electrode of the 2nd kind: A metallic electrode whose response is proportional to the logarith of the concentration of an anion that forms either sparingly soluble species or stable complexes wit ha cation derived from the electrode metal. Electronic transition: The promotion of an electron from one electronic state to a second electronic state. End point: point in a titration when a physical change occurs that is associated with the condition of chemical equivalence. Equivalence point: point in a titration when the amount of added standard reagent is equivalent to the amount of analyte Gravimetric method: quantitative methods that are based on determining the mass of a pure compound to which the analyte is chemically related. Gross error: An occational error, neither random nor systematic, that results in the occurrence of a questionable outlier result. Indicator electrode: An electrode whose potential is related to the activity of one ore more specied in contact with the electrode, varying potential. Isomation methods: setting the concentration of an analyte equal to the concentration of a dilute standard. Liquid junction: The interference between two liquids with different composition. Monochromatic radiation: electromagnetic radiation that consists of a single wavelength. Nucleation: A process involving formation of very small aggregates of a solid during precipitation. Null hypothesis: A claim that a characteristic of a single population is equal to some specified value or that two or more population characteristics are identical. Optical methods: methods based on ultravoilet visible and infrared light Peptization: A process in which a coagulation colloid returns to its dispersed state. Polychromatic radiation: Electromagnetic radiation consisting of more more than one wavelength Precipitation gravimetry: the analyte is converted to a sparingly soluble precipitate filtered and weighed. Primary standard: an ultrapure compound that serves as a reference material for a titration. Random error: Uncertainties resulting from the operation of small uncontrolled viarbles that are inevitable as measurement systems are extended to and beyond their limits Reference electrode: An electrode whose potential relative to the standard hydrogen electrode is known and against which potentials of unknown electrodes may be measured, completely independent of the analyte concentration. Secondary standard: compound whose purity has been determined by chemical analysis. Stray light: Radiation of a wavelenght other than the wavelength selected for optical measurements. Supersaturated solution: an unstablesolution that contains a higher solute concentration than a saturated solution. Systematic error: Errors that have a known source, they affect measurements in one and only one way and can be accounted for. Titration error: The difference between the titrant volume needed to reach an end point in titration and the theoretical volume required to obtain an equivalence point. Titration methods: based on determining the quantity of a reagent of known concentrations that is required to react completely with the analyte. Type I error: when the null hypothesis is rejected althought it is actually true. Type II error: when the null hypothesis is accepted and is false. Volatilization methods: A variant of gravimetry based on the loss of mass caused by heating.