Essay about Quantitative Analysis Cheat Sheet

6265 Words Mar 28th, 2014 26 Pages
Chapter 1: Measuring the amount of substance
Analytical chemistry: science of chemical measurement. Its object is the generation, treatment and evaluation of signals from which information is obtained on the composition and structure of matter
Measurement: process of obtaining the magnitude of a quantity
Example: The amount of saturated fat in the sample is 3 g/serving.
Quantity: attribute of a phenomenon that may be distinguished qualitatively and determined quantitatively
Value: magnitude of a particular quantity expressed as a unit of measured * a number
Unit: particular quantity defined and adopted by convention for comparison of magni
 Globalization requires comparability of measurements
Metric system: Meter Convention
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Burets (used to deliver multiple aliquots of a liquid in known vols – tolerance: ½ the smallest graduation)
Correct use of buret: read buret at bottom of concave meniscus, read at eye level (avoids parallax errors, from above: smaller), estimate buret reading nearest 0.1 division, expel all air bubbles, rinse buret 2-3x with solution, near end of titration, volume of 1 drop or less
2. Volumetric flask:correct use: add reagent of solution to flask and dissolve in volume of solvent less than total capacity of flask, slowly add more solvent until mark, mix solution by inversion (40 or more times), glass adsorbs trace amount of chemicals  clean using acid wash (adhere to surface)
3. Pipets and Syringes (deliver a given volume of liquid) Types of pipets: transfer pipet (transfers a single volume, fill to calibration mark, last drop does not drain out of pipet (do not blow out), more accurate than measuring pipet(similar to vol flask) measuring pipet: calibrated similar to buret, use to deliver a variable volume micropipette: deliver volumes of 1 to 1000 µL(fixed and variable), uses disposable polypropylene tip, stable in most aqueous and organic solvents (not chloroform), need periodic calibration syringes: deliver volumes of 1 to 500 µL (accura&prec: 0.5-1%, steel needle permits piercing stopper to transfer

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