Density Determinations

Experiment #2 “Density Determinations” Report The objective for experiment #2 was “to determine densities of objects/salt solutions with different concentrations of salt, to see how density changes as a function of concentration.” In experiment #2, part II, calculations of Density of NaCL solutions were made from 0%-25% NaCL concentration. My hypothesis was that as the % increased, so would the density, because adding weight would increase the density of each solution. The density calculations in part II, were precise and accurate within + 0.03 g/cm^3. The results for this experiment prove that as you increase % of NaCL, the density increases also because of the weight of NaCL is increased. Graph #1 shows that as the %NaCL increased so did the density, therefore proving the accuracy and precision of part II calculations. In part III, of the experiment, the density of regular shaped objects, were calculated based on volume measured method and water displacement method. My hypothesis for this part of the experiment was that volume measured method would be more accurate because water displacement method contains too many random errors. The density calculations of volume measured for part III were both more precise and more accurate within a standard deviation of + 0.06 g/cm^3, where water displacement method had a standard deviation of + 0.15 g/cm^3. Graph #2 shows the error was greater according to water displacement method when measuring the initial and final volume’s displaced with a standard deviation of + 2.0 g/cm^3. The average calculated density of the regular shaped objects compared to the graphical determination were within + 2g/cm^3 standard deviations. The accuracy and precision, when comparing the graph with the average calculated density, shows that human error when measuring water displacement can make a big difference in the outcome of the answer. The test tubes used to measure were only capable of measuring in 1 digit, where the calculations were