6.03 Calorimetry Lab

Synopsis

This laboratory report gives an outline of the experiment which was carried out in order to measure the density of water at different temperatures via two different methods. The lab consisted of two parts. In the first part the density of water was measured by hydrometer. At first the density of water at room temperature was measured. In the next steps the density of water between 30-40 °C, 40-50 °C and 50-60 °C was measured. Then our results ρ vs T and also density vs temperature values given in the Steam Tables were plotted on the same graph in order to compare. In the second part the density of water was measured by density bottle. The densities obtained from the experiment are 995, 992.5, 991, 990 kg/m3 for the first part and

Again we will use ρ=m/V in order to calculate the density of water.

Experimental technique

The first part of experiment is done in following steps:

The second part of experiment is done in following steps:

Results

The density of water by using hydrometer:
1. 26.5 °C room temperature
2. 37.8 °C and 36.3 °C 30-40 °C
3. 41.7 °C and 40.2 ° C 40-50 °C
4. 50 °C and 48 ° C 50-60 °C Average temperatures:
(37.8+36.3)/2=37.05 °C
(41.7+40.2)/2=40.95 °C
(50+48)/2=49 °C

Table 1 -The values of experiment
Temperature (°C) Density (kg/m3)
26.5 995
37.05 992.5
40.95 991
49 990
70 984.856
80 982.524
90 980.272
100 977.93

Table 2. The values in steam table

Temperature (°C) Density (kg/m3)
26.5 997
37.05 993
40.95

These small errors may be arised as a result of temperature. Because the accurate mesuring process took much time and during this time the temperature of water was decreasing. Among two methods the density bottle gives more accurate measurement of the volume, resulting in more accurate determination of density. One of disadvantages of hydrometer is that hydrometer has Operator dependent readings, therefore has limited accuracy. Morever, for measuring the density using hydrometer large sample volume is required.

Conclusion
In conclusion, almost our group reached main target. We used two different methods which were hydrometer and density bottle method in order to measure the density of water at different temperatures. We calculated the densities of water which were 995, 992.5, 991, 990 kg/m3 for the first part and 967 kg/m3 for the second part. Finally we compared these two methods in order to decide which method is more suitable.
References

http://www.middleschoolchemistry.com/lessonplans/chapter3/lesson1 http://chemistry.about.com/od/waterchemistry/f/What-Is-The-Density-Of-Water.htm