Introduction : Density can be defined by the mass of the substance over the volume which this substance occupies. This is described by the well known equation D=m/ V, where D is the density of the substance, m is the mass of the substance and V is the volume occupied by the substance. The typical units for density are g/mL. Density is an intensive property of matter. This means that it does not depend on the mass of the substance present but rather on the nature of the substance. Each pure substance has a defined, unchanging density. As a result, density is very useful in determining the identity of an unknown liquid. The purpose of this experiment was to determine the identity of an unknown liquid based on its density using a procedure that we designed in order to maximize the precision and accuracy of our measurements of the liquid’s density. Experimental Procedure : Part I: Distilled Water : The procedure was first tested on samples of distilled water, which is known to have a density of about 0.997 g/ mL. 1. Distilled water was obtained in a 50mL beaker 2. A 30 mL beaker was cleaned, dried and massed on an analytical balance. The analytical balance was chosen because provided a greater degree of precision because it provided the mass to three decimal places. This mass was recorded. 3. 10.00mL±0.04mL were measured in a clean calibrated pipet and placed in the 30mL beaker. The pipet was used because it provided a greater degree of precision than the graduated cylinder, which provides an uncertain measurement in the tenths place. (Before actually using the pipet for the procedure, the amount delivered by the pipet was initially tested by measuring the amount of distilled
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