Analytical Chem istry - DePauw University

Chapter 2 Basic Tools of Analytical Chemistry352IChapter SummaryThere are a few basic numerical and experimental tools with which youmust be familiar. Fundamental measurements in analytical chemistry, suchas mass and volume, use base SI units, such as the kilogram. Other units,such as energy, are defined in terms of these base units. When reportingmeasurements, we must be careful to include only those digits that aresignificant, and to maintain the uncertainty implied by these significantfigures when transforming measurements into results.The relative amount of a constituent in a sample is expressed as a concentration.There are many ways to express concentration, the most commonof which are molarity, weight percent, volume percent, weight-to-volumepercent, parts per million and parts per billion. Concentrations also can beexpressed using p-functions.Stoichiometric relationships and calculations are important in manyquantitative analyses. The stoichiometry between the reactants and productsof a chemical reaction are given by the coefficients of a balanced chemicalreaction.Balances, volumetric flasks, pipets, and ovens are standard pieces ofequipment that you will routinely use in the analytical lab. You should befamiliar with the proper way to use this equipment. You also should befamiliar with how to prepare a stock solution of known concentration, andhow to prepare a dilute solution from a stock solution.2JProblems1. Indicate how many significant figures are in each of the following numbers.a. 903 b. 0.903 c. 1.0903d. 0.0903 e. 0.09030 f. 9.03x10 22. Round each of the following to three significant figures.a. 0.89377 b. 0.89328 c. 0.89350d. 0.8997 e. 0.08907Answers, but not worked solutions, tomost end-of-chapter problems are availablehere.3. Round each to the stated number of significant figures.a. the atomic weight of carbon to 4 significant figuresb. the atomic weight of oxygen to 3 significant figuresc. Avogadro’s number to 4 significant figuresd. Faraday’s constant to 3 significant figures4. Report results for the following calculations to the correct number ofsignificant figures.a. 4.591 + 0.2309 + 67.1 =