igure 1.6 Common types of laboratory equipment used to measure liquid volume. !5 Figure 1.7 easurement of volume using a buret. The volume is read at the bottom of the uid curve (called the meniscus). 100-mL graduated cylinder 1.4 Uncertainty in Measurement 11 Calibration f1 mark indicates I j 2S-mL volume--2S-mLpipet-, ,-, ( \ f Calibration mark indicates 2S0-mL volume-44 4S 46 47 48 49 11-'1 SO Valve (stopcock) controls the liquid flow-SO-mL buret 2S0-mL volumetric flask 1.4 ~ Uncertainty in Measurement The number associated with a measurement is obtained using some measuring device. For example, consider the measurement of the volume of a liquid using a buret (shown in Fig. l.7 with the scale greatly magnified). Notice that the meniscus of the liquid occurs at about 20.15 milliliters. This means that about 20.15 mL of liquid has been delivered from the buret (if the initial position of the liquid meniscus was 0.00 mL). Note that we must estimate the last number of the volume reading by interpolating
This is the end of the preview. Sign up
access the rest of the document.
This note was uploaded on 12/13/2010 for the course CHEM 2301 taught by Professor Bill during the Spring '10 term at South Texas College.