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Unformatted text preview: 3-1 Experiment 3 MASS, VOLUME AND DENSITYI. Learning Objectives To measure the density of a nonane at room temperature. To examine the effects of temperature on density. II. Background Information An important intensive propertyof every substance is its density. People float in water because they are less dense than water. Concrete, on the other hand, is much denser than water and sinks rapidly. Helium balloons float in the air because helium is much less dense than the surrounding atmosphere, which is composed primarily of nitrogen and oxygen. The density of a substance is equal to the mass of that substance divided by its volume. volumemassdensity =The S.I.units of density are kilograms per cubic meter (kg/m3). Because chemists usually deal in smaller amounts, density is frequently expressed in grams per cubic centimeter (g/cm3) or grams per milliliter (g/mL). The density of a liquid is determined by first weighing an empty container. Then, the container is weighed with a known volume of liquid inside. This simple experiment provides the two necessary pieces of data (mass and volume) needed to determine the density. When two liquids are mixed together, the volumes are usually additive. When a solid is dissolved in a liquid, there is frequently no apparent volume change, however, the density of the solution is greater than that of the pure liquid. It is well known that air expands when heated; this is why hot air balloons float (heated air is less dense than surrounding air). Liquids and solids also expand and contract as the temperature rises or falls, but the magnitude of this effect is much less dramatic than 3-2 observed with gases. Table 3.1 shows the density of nonane, an organic solvent, at various temperatures. In this experiment accurate measurements are made that allow the determination of the difference in density between nonane at room temperature and heated nonane. Note: Room temperatureis defined in the laboratory as 25C or 298 K. Table 3.1Density of Nonane as a Function of Temperature Temperature (oC) Density (g/mL)0.7327100.7252200.7176300.7099400.7021500.6941600.6861700.6779800.6696900.66111000.6525IV. ProcedureNote: Perform the following procedure with a lab partner using only one computer. Make sure both partners have a copy of the collected data for use during the work up of the lab. EXPERIMENTAL SETUP A. Hardware Setup1. Start the computer. 2. Check that the Science Workshop 500 interface is connected to the power source. When the interface is properly connected, the green power light is illuminated. 3. Connect the computer to the interface using the cable provided. Attach the cable to the USB port of the computer....
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- Fall '08