Chemistry Practical Investigation-Volumetric Analysis

There are several sources of error to this experiment due to random and systematic errors. The only source of random error was the measurement that we took through the graduated cylinder which was only accurate to the nearest 1%. We took the largest error from this one percent, which was +/- 3. The largest relative error this yielded was only 3%, so this did not affect how precise this experiment was too much. We can still make this more precise by making the masses of the water larger. For example if we started the masses at 300mL and went up by 50mL, the largest error this would yield would be 2% due to the largest error being +/- 5. This would cause smaller errors in the amount of water.

    One possible source of error that can affect the results was that a mercury thermometer was used instead of an electronic one. The use of a mercury

In this lab experiment our main focus was to get skillful in using tools such as the metric ruler, balances, thermometer, and graduated cylinder to capture measurements of length, mass, temperature and volume. Additionally, this lab helped us to become more familiar with the uncertainty of measurements, as well as becoming efficient with rounding our measurements to the correct numbers of significant figures. Our results are measured consistently with rounding to the closest answer we could possibly acquire as the data can tell you.

According to the data I collected, accuracy and precision do remain for the most part constant for the different volumes. I was the most accurate during one of my measurements of 200 µL, but I was the most precise with my measurements of 25 µL and 50 µL.

The slope, found by the rise over run of 4.5 over 4, tells the average density for the samples.

Prepare standard solution #1, Take 1 ml sub stock solution from the 100 ml beaker and then put into 25 ml volumetric flask with the help of 10ml graduate pipette.

This lab was not repeated to examine for consistent results, which may result in data where precision and accuracy are compromised. In this investigation,

Volume of water This was kept constant by using a 200 ml beaker to fill up the jars used in the experiment. The uncertainty of the volume of the water was: +/- 10 ml

The experimental error in this lab included the question whether the digital scale was as precise as it could be, how the cooling time affected the water in the hydrates, and any miscalculations that could have occurred. The digital scale could have been more precise since they are more precise scales that could deliver more accurate masses in this lab.

First, we added water to the graduated cylinder to 20 mL. Then, placed the unknown substance in the water, the water increased and measured 25 mL. The volume was determined by subtracting 20 mL from 25 mL. The volume equaled 5 mL for the unknown substance. Next, we filled the water to 20 mL in the graduated cylinder. Then, placed aluminum in the water, the water increased and measured 25 mL. The volume was determined by subtracting 20 mL from 25 mL. The volume equaled 5 mL for aluminum. After that, we added water to the graduated cylinder to 20 mL. Then, placed the zinc in the water, the water increased and measured 22.5 mL. The volume was determined by subtracting 20 mL from 22.5 mL. The volume equaled 2.5 mL for zinc. Last, we added water to the graduated cylinder to 20 mL. Then, placed lead in the water, the water increased and measured 24 mL. The volume was determined by subtracting 20 mL from 24 mL. The volume equaled 4 mL for

The percent uncertainty for beakers was not calculated. The beakers were only used for storing the solutions. Therefore, the accuracy of the beakers did not affect the outcome of the

2. Both the measurements of temperature and volume limit the precision of the data because for temperature, we could only round to the nearest tenth, which limits the amount of sig figs. In addition, because the total volume was only 50mL, there could have been another volume that would have exceeded the optimal ratio of this experiment.

As with many experiments that are performed in a setting where we cannot be exact on every measurement, error could arise from it. For instance, from this particular experiment, we needed to measure 5mL of water and 5mL of the borax mixture after it had cooled. Measuring 5mL with the bulb pipet that we were provided was not an exact measurement tool. The pipets provided were not calibrated and/or could have contained pockets of air with the assumed 5mL of water or solution.

With this experiment, I felt there were a number of possible scenarios of error. The first part I notice that could have caused an error in my overall sample was at the start of the experiment I heated my unknown and the flask in a beaker of water that was not boiling yet for several minutes. Once I noticed my mistake I heated the water until boiling temperature recorded the degrees and continued on with my experiment. The next part of my experiment that may have caused error to my overall sample was while I was lowering my sample into the beaker of boiling water the utility clamp was not working properly and forced my sample to touch the walls of the beaker. This could have effect my overall result.

This experiment shall be repeated twice or more to enhance accuracy of the results obtained. Besides detecting systematic errors, this experiment would aid on the technique and understandings to the correct use of these equipments.