LabReportSample

# LabReportSample - Name Instructor AP Chemistry, Period Date...

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Name Instructor AP Chemistry, Period Date Determination of the Density of a Wood Sample Lab Report I. Introduction/Purpose: To determine the density of a wooden sample using a restricted number of materials to the best accuracy possible. The density of an object is =mass/volume. The concept of Archimedes Principle was used to determine the mass and volume. When an object is freely floating, the mass of the displaced liquid is equal to the mass of the object. By re-arranging density = mass/volume, it can be shown that mass = density x volume. Since the density of water is equal to 1.0 g/ml, then the volume of the displaced water is equal to the mass of the object. When an object is fully submerged, the volume of the water displaced is equal to the volume of the object. II. Materials: Wood sample (Popsicle stick), Large test tube, water, dropper (pipette), pen, felt marker, a 10 ml graduated cylinder, a 100 ml graduated cylinder, and an electronic balance. III. Procedures and Data Collection: III. A. Calibration of the Pipette Four volumes, 0.5, 1.0, 2.0, and 3.0 ml, were chosen to calibrate the pipette with. Draw water into the pipette and count each drop as it fills the graduated cylinder. Once it has reached the desired volume, record the number of drops. For each volume, the experiment was performed in triplicate. The results are shown in Table 1. The calibration curve of average volume vs. drops is obtained by linear regression using Microsoft Excel. Table 1: Number of drops of water from the pipette vs. volume (ml). Experiment # Drops of water from pipette Volume (ml) 1 33 0.50 1 33 0.47 1 33 0.45 2 65 1.00 2 65 1.04 2 65 1.10 3 130 2.00 3 130 2.12 3 130 2.02 4 195 3.00 4 195 3.11 4 195 2.97

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III. B. Determination of the Mass of the Wood Sample by the Dropper Method Once the pipette has been calibrated, fill the large test tube with water and mark the water level with the felt marker on the test tube. Next, gently place the floating Popsicle stick inside the test tube, which causes the water to rise, and mark the new water level. Carefully pipette the water displaced between the two marks into an empty test tube. The volume of the displaced water is measured by counting the drops of water from the pipette into the other test tube. Each experiment is performed in triplicate. The volume of the drops of water is determined from the calibration curve. The mass was calculated by multiplying the volume with the density of water
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## This note was uploaded on 12/07/2011 for the course CHEM 100 taught by Professor Feebeck during the Fall '10 term at Purdue University-West Lafayette.

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LabReportSample - Name Instructor AP Chemistry, Period Date...

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