The precision of a 50 ml beaker, 25 ml grad. cylinder., and a 25 ml pipette were determined by transferring each type to a tared 50 ml beaker. The density of copper was determined through volume displacement in water. The pipette was fond to be the most precise with a mean volume of 24.843±0.184ml. While the 25 ml cylinder had a volume of 24.601±0.708 ml and the 50 ml beaker had a volume of 24.074±1.98 ml. The density of copper was found to be 9.190±0.836, with an accuracy of 2.567%. The difference in density measurements could be due to human error or temperature differences.
Background: Previously submitted on D2l.
Procedure: Hirko, R. Chemistry 112L General Chemistry I Laboratory, Ninth Edition; bluedoor: Minneapolis, 2015; Experiment 1.
Results:
Vessel T/°C H2) Mass/g Density/ g/cc V/ mL
50 mL beaker 21.1° 23.454 0.99797 23.502
50 mL beaker 21.1° 24.935 0.99796 24.986
50 mL beaker 21.1° 23.687 0.99797 23.735
Mean Volume 24.074
Uncertainty 1.98
25 mL grad. Cyl. 20.7° 24.806 0.99799 24.292
25 mL grad. Cyl. 20.9° 24.268 0.99804 24.854
25 mL grad. Cyl. 20.8° 24.609 0.99802 24.657
Mean Volume 24.601
Uncertainty 0.708
25 mL pipette 21.4° 24.837 0.99791 24.889
25 mL pipette 21.3° 24.829 0.99789 24.881
25 mL pipette 21.3° 24.706 0.99792 24.757
Mean Volume 24.843
Uncertainty 0.184
Trial 1 Trial 2 Trial 3
Mass dry cylinder /g 27.250 27.337 27.260
Mass dry cylinder + metal / g 61.331 61.415 61.335
Mass dry cylinder + metal + water to 10.00 ml mark 67.961 67.487 67.410
Mass metal / g 34.081 34.078 34.075
Mass water/ g 6.63 6.072 7.075
Volume water/ cc 6.644 6.085 6.088
Volume metal / cc 3.356 3.915 3.912
Density metal / g/cc 10.155 8.704 8.71
Mean Density ± Uncert...
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... error that may be present is inconsistent temperatures. In each of these trials temperature was never measured to make sure the number was actually 21°C. This temperature discrepancy could lead to inaccuracies in finding the mean density.
To improve part 2 of this experiment more accurate measurements are needed. More time needs to be spent on obtaining an accurate measurement of water up to the 10 ml line. Temperature also needs to be taken before each trial to accurately calculate the mean density for each trial. Adding a trial with a liquid, other than water, would require changes in the numbers used to calculate the density of the metal, but could provide additional data to confirm the density found.
Acknowledgements:
I would like to recognize my lab partner Chad White for assistance in the experiment, my TA Amos Dwamena, and my lab coordinator Mandy Orth.
2. Cooper, M. M., Cooperative Chemistry Laboratory Manual, McGraw-Hill: New York, NY, 2009, p. 60.
The complete experimental procedure is available in the General Chemistry Laboratory Manual for CSU Bakersfield, CHEM 213, pages 20-22, 24-25. Experimental data are recorded on the attached data pages.
the replicate shows the same trend as the first experiment. I used a measuring cylinder and a beaker to measure out the amounts of water; however these did not seem to affect the quality of my results. To increase the accuracy of my results I could have perhaps used a burette. Even though I did the best I could to keep the experiment accurate, I did. some places there were mistakes that unintentionally occurred.
Discussion: The percent of errors is 59.62%. Several errors could have happened during the experiment. Weak techniques may occur.
Over the observed fifty seconds, there was a consistency among the temperatures. Without a calculated percent error, we are able to assume the average temperature was twenty-six degrees Celsius. There are factors that could have caused error to arise in our data collection. One factor could be that the temperature of the room was not consistent throughout the room. Another factor may have been the performance of the thermometer. The grasp in which the thermometer was held for procedure B may also be a factor.
Volume's Effect on a Copper Sulphate Solution We are trying to find out if the current though a copper sulphate solutions volume is increased. To find this information out I shall perform an experiment using the following equipment; · 1 power pack · 1 beaker · 2 carbon rods for anode and cathode · 1 ammeter · 1 measuring cylinder · 2 crocodile clip wirers I shall also be using 60cm3 volume of copper sulphate in my preliminary results to decide upon the concentration of copper sulphate and the voltage I shall use. The following diagrams show the step by step process in which I will do my experiment; [IMAGE] [IMAGE] [IMAGE] [IMAGE] I will take 10 readings from 10cm3 to 100cm3. I will repeat my experiment to give my experiment a fair average. I will keep the power pack the beaker the carbon rods the crocodile clips the ammeter the concentration of copper sulphate and the measuring cylinder the same each time I do the experiment this experiment.
The molar volume of the H2 in our experiment is very close to the theoretical molar volume, but I think that the deviation lies in the temperature of the H2O: in the first trial it is too high and in the second one too low.
In this experiment, there were several objectives. First, this lab was designed to determine the difference, if any, between the densities of Coke and Diet Coke. It was designed to evaluate the accuracy and precision of several lab equipment measurements. This lab was also designed to be an introduction to the LabQuest Data and the Logger Pro data analysis database. Random, systematic, and gross errors are errors made during experiments that can have significant effects to the results. Random errors do not really have a specific cause, but still causes a few of the measurements to either be a little high or a little low. Systematic errors occur when there are limitations or mistakes on lab equipment or lab procedures. These kinds of errors cause measurements to be either be always high or always low. The last kind of error is gross errors. Gross errors occur when machines or equipment fail completely. However, gross errors usually occur due to a personal mistake. For this experiment, the number of significant figures is very important and depends on the equipment being used. When using the volumetric pipette and burette, the measurements are rounded to the hundredth place while in a graduated cylinder, it is rounded to the tenth place.
Repeat using the SAME metal sample, but instead with the colder water. Do not record the temperature of the cold water in the calorimeter until immediately before adding the heated metal.
One possible source of experimental error could be not having a solid measurement of magnesium hydroxide nor citric acid. This is because we were told to measure out between 5.6g-5.8g for magnesium hydroxide and 14g-21g for citric acid. If accuracy measures how closely a measured value is to the accepted value and or true value, then accuracy may not have been an aspect that was achieved in this lab. Therefore, not having a solid precise measurement and accurate measurement was another source of experimental error.
Polman, H., Orobio De Castro, B. & Van Aken, M. A.G. (2008). Experimental Study of the
Schreuder, Jolanda A. H.; Roelen, Corné A. M.; van Zweeden, Nely F.; Jongsma, Dianne; van der Klink, Jac J. L.; Groothoff, Johan W.
There is also the potential of human error within this experiment for example finding the meniscus is important to get an accurate amount using the graduated pipettes and burettes. There is a possibility that at one point in the experiment a chemical was measured inaccurately affecting the results. To resolve this, the experiment should have been repeated three times.
Possible sources of error in this experiment include the inaccuracy of measurements, as correct measurements are vital for the experiment.
Plontke, R. (2003, March 13). Chemnitz UT. TU Chemnitz: - Technische Universität Chemnitz. Retrieved April 1, 2014, from http://www.tu-chemnitz.de/en/