The average concentration of my unknown Al3+ solution (#41) was 0.02372 0.00016 mol/L. My %RSD was 0.67%, which I would say is very good. This means my precision relative to my average was very good. When calculating the mass of the precipitate, my Trial #1 and #2 were both 0.271X, with Trial #3 being 0.27XX. Having Trial #1 and #2 being only 1 decimal place different from each other was very surprising to me, and indicated high precision. This led to a low standard deviation and a low %RSD. I think consistency of observations was what led to a high precision for me. When I added reagents to the Al(NO3)3, all the trials typically had the same observations. I stopped adding things like HCl and ammonium acetate immediately after I saw a stable …show more content…
(1) If the crucibles were not put in the oven at the end of the experiment, there could be excess moisture trapped in the crucible. This contributes to the mass of the weighed crucible at the end of the experiment, meaning the mass would be higher than it would normally be. After calculations, it can be concluded that the moisture in the crucible shifts the data up, creating an artificially high concentration of Al3+. (2) Reading the volumetric pipet to 25.00mL is an incredibly crucial step in this experiment because it’s the only source of Al3+ that is added to the reaction. This step affects the end result when weighing the precipitate because in the reaction, the Al3+ is the limiting reagent and is in a 1:1 stoichiometric ratio with the precipitate product. If the pipet is read too low, then the result would be an artificially low concentration because the mass would be lower. If the pipet is read too high, then the result would be an artificially high concentration because the mass would be higher. (3) On Day 3, if we did not rewash the beaker with DI water after initially pouring the solution into the crucible to be filtered, it would affect the final results of the experiment. If the beaker was not washed, not all the solution/precipitate would end up in the crucible/filtration system, which would mean a possible low reading on the mass and concentration of Al3+ because some of the precipitate would remain on the beaker. The precipitate left on the beaker would not be accounted for in the calculations, and would result in a lower measured mass and
Conclusion: Compare Trial 1 and Trial 2. The Trial 1 change in mass are 12.5g, however Trial 2 changes in mass is 1.2g. The Trial 1 change in mass is more than Trial 2. And I think the Low of Conservation of Mass violated in the Trial 1 is can be exist. Because the Trial 1 actually the soda with vinegar have Chemical reactions occur and chemical
Fill beaker with water Use the disposable pipette to place water in the graduated cylinder until the unidentified object would be completely submerged in water Record what the measurement of water in milliliters before placing the unidentified object into the graduated cylinder Gently place the unidentified object into the graduated cylinder Record the measurement of the water in milliliters after placing the unidentified object into the graduated cylinder Subtract the measurement of water in milliliters before placing the unidentified object into the graduated cylinder from the measurement of the water in milliliters after placing the unidentified object into the graduated cylinder, this is the volume of the unidentified object Record the volume (the answer you got in step 10) of the unidentified object in the data table Weigh the unidentified object on the scale, this is the mass of the unidentified object Record that number in the data table Calculate the density of the object by dividing the mass by the volume and rounding it to the proper significant figure, Record the density of the unidentified object in the data table Repeat the lab 2 more times and with each experiment record the data in the chart under the correct trial number corresponding with the correct
After seemingly all of the aluminum chloride has been funneled from the copper, one should take the filter paper out of the funnel and let it dry. One needs to let the filter paper dry before weighing it to see how much copper was produced in order to allow the water to evaporate. If one were to weigh the funnel paper while it was wet, they would not get an accurate measurement of how much copper was produced because the scale would show a reading of the amount of copper as well as the amount of water on the filter paper. Once the filter paper has fully dried, one can then weigh the paper in order to determine how much copper was produced. In order to do this one should take a scale and obtain a clean piece of filter paper along with the one with the copper on it.
Now, they are ready to start the lab. The empty crucible is weighed by and the weight was recorded. Then the students used a disposable pipet and put close to 4.0 grams of their milk sample in their crucible on the scale. The crucible was then placed back on
In all trials, some of the precipitate was lost through the filter. Therefor all values are most likely less than the actual values due to
(1) The purpose of the separation lab procedure was to help my group members and I successfully formulate our own plan before completing the experiment, handling multiple materials and substances, etc. It acted as a step-by-step plan that guided us throughout the experiment and ensured that we were well prepared ahead of time (ie. knowing what kind of materials were necessary and gathering the correct measurements of each substance); this made the experiment day much less hectic for all of us. It made reaching our goals (achieving > 85% recovery for each substance) more realistic and convenient. (2)We predicted that we would be able to easily separate each substance from the mixture through the use of our designed procedure. By using a bar magnet, we predicted that all the iron (and only the iron) would attract and quickly maneuver its way through the beaker and into the
Error Analysis We may have made a few errors along the way. We could have had a blunder because we may not have waited long enough for the penny to stay on the scale. We could have made a human error because we could have had a little more or less sodium hydroxide in our graduated cylinder and eyeballed it wrong. Another error you could have made was an instrumental limitations because read the cylinder wrong on the side by
The powder on the filter paper could've fell and this caused it to have a smaller percent purity, percent yield and also cause a lower absorbance and concentration of pure ASA. Another error would be not using a properly dried sample for the pure ASA in part C when making the crystals, this could have cause tye percent yield error. This would make a lower melting point. To prevent this from occurring next time there could be a dry sample that is completely dry and this would not alter the mass of the sample and this would make the solution have a more
Elijah Brycth B. Jarlos IX-Argon 1. Multicellularity is a condition of an organism to have multicellular cells. An example of a organism who has multicellular cells are plants, animals, and humans. The main reason of why scientists have a hard time finding a good set of existing organisms to compare. Is neither the first set of organisms which is being compared is dying as fast as the second specimen is being examined or they just can’t find the right species.
The final mass could be far off due to the water and chunks of expanded gummy bears found in the beaker, leading to an inaccurate result. As well, for the sugar solution, the result could have been different if a more accurate measurement of the sugar needed was made. For the specific result, the hypothesis stated, the sugar solution needed to have an equal amount of sugar content to the gummy bear which did not occur. Ensuring that the beaker contained 10 grams of sugar was off, due to prerequisite calculations that lead to too much liquid in the beaker that needed to be removed. To be correct, the hypotheses that were wrong could
It was impossible to accurately measure the volume of liquid at any given moment, as the meniscus was moving side to side. Secondly, the distillation was ended while there was still liquid in to round bottom flask. The composition and volume of this liquid were unaccounted for in the calculated
The actual data is the result on our experiment vs theoretical, which is based on the calculations above. I have also learned to pay more attention to draining out all of the product completely before continuing to test the experiment, as any small drop of contaminant can veer our results into a different
The data was handled accurately, values clearly labeled and calculated in the correct procedure. The procedure of reacting magnesium with oxygen was most likely the source of error. It is possible that the magnesium strip had not completely reacted with oxygen yet when I took the crucible off the burner and dropped distilled water into it.
Also, although this likely served no contribution in disheveling the results, using a stirrer of the same material to ensure the separate testing of each substance will be as uniform as
In this experiment, the amount of water lost in the 0.99 gram sample of hydrated salt was 0.35 grams, meaning that 35.4% of the salt’s mass was water. The unknown salt’s percent water is closest to that of Copper (II) Sulfate Pentahydrate, or CuSO4 ⋅ 5H2O. The percent error from the accepted percent water in CuSO4 ⋅ 5H2O is 1.67%, since the calculated value came out to be 0.6 less than the accepted value of 36.0%.This lab may have had some issues or sources of error, including the possibility of insufficient heating, meaning that some water may not have evaporated, that the scale was uncalibrated, or that the evaporating dish was still hot while being measured. This would have resulted in convection currents pushing up on the plate and making it seem lighter by lifting it up