IV. CONCLUSION _
In this experiment, a solution of Na2CO3 was reacted with a solution of CaCl2 to form a precipitate of CaCO3. The theoretical yield of CaCO3 was calculated and then compared to the actual yield of CaCO3. The results suggest that the Theoretical Yield was 4.2246 grams and the Actual Yield was 4.24 grams, which gave a Percent Yield of 100.473% and a Percent Error of 0.473%. The actual yield was greater than the theoretical yield. It is suggested that it was greater than because I used two different filter papers and I only measured one. If I had measured the two different papers, I would probably obtain a different mass for each of them. Because I am only off by 0.02 grams, that could have been the reason why I didn’t get the mass I should have obtained. After finishing my experiment I measured another filter paper and it weighed 0.928 (Image #2). It is very possible for one of the filter
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The main strength in the method was the procedure, because it clearly and briefly explained the steps needed to take. Following my method was easy, because it was very clear and easy to follow. However, the method did not include many photos of the set-up and of the experiment overall. The main weakness in the method was the lack of photos of how I set-up my materials and of observations I made during the experiment (Separating the precipitate from the water, the water, the precipitate before and after drying) to further explain and extend the understanding of the reader. In following this method it was difficult to understand some of the last steps and the set-up because of the lack of photos. An improvement to the method would be to measure the mass of both filter papers. I would make this improvement because if I had done that before my final result would be closer to the Theoretical
Mole of chlorine : 1.0217g - .221g - .3946 g = .4061 g of chlorine
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.
For the Mole lab, my team claimed there was 1,992 beans in the large display jar. The estimate was close but still off by 59 beans. The actual amount of beans in the jar was 2,051. To figure out our estimate we used a beaker of beans to experiment with. We first found the tare weight of the beaker, which was 49.912, and the weight of the beaker with the beans, 95.301. Our next step was the weight ten beans of different sizes and find the average of the beans. We found the average weight of the beans to be .47g. After doing this we then subtracted the weight of beaker with the beans from the tare weight to find the weight of the beans. We found the weight of the beans to be 45.389g. After finding the weight of the beans we dived that by he average weight of our ten beans and got 97 beans in our beaker. When we counted our beans in our beaker, we found it to be 105. We then repeated this test but using the tare
The cup with the second greatest change in mass of the rock was number 2. Cup 2 had the solution of 10% vinegar and resulted in the change of -0.3g. Lastly, Cup 3 with distilled water had the lowest change in the mass of the rock, of 0g. It was hypothesized at the beginning that Cup 3 with distilled water would have the least amount of change, if any. This hypothesis was correct. Water is not acidic, so there would be no reason for the rock to change. When the hypothesis was conducted, it was based on the pH level. Instead, the actual solution should have been taken into consideration. The fact that the soda water would eventually lose its carbonation and become flat within a few days. Therefore, taking the acidity away. The experiment was done correctly, and there did not need to be any changes. Just the hypothesis could have been more thoroughly
We then proceeded in testing for excess Ca2+ by adding two drops of .5 M K2C2O4 to test tube two and attentively observed to see if a precipitate formed, which it did. This meant that Ca2+ was in excess and C2O42- was the limiting reactant in the original salt mixture. We then cleaned up. Upon returning to our next class, we took the filter paper, with the precipitate on it, and took its mass.
The purpose of this lab was to find out how gaviscon reacted with different salt solutions. Sodium Alginate is a compound that forms with the Gaviscon and forms a “raft” and blocks all the stomach acid from traveling up the esophagus.
3. When the anhydrous sample was rehydrated, only 93.4% of the sample could be recovered. This was because some of the mass of the sample remained stuck to the filter paper and could not be measured in the final mass calculation. This automatically resulted in less mass and did not allow for 100% of the mass to be recovered.
When compared to the theoretical value, we had a 2.6% error in our experiment. Any errors that occurred maybe due to a too low intensity
Turning to over-the-counter drugs has become a necessity for those seeking fast and easy pain relief. Several medications have been noted as beneficial and effective, and although Alka-Seltzer tablets, used for pain relief, as an antihistamine, and for nasal decongestion, has not reached the most commonly used, its effectiveness can be proven.2 Dissolved in water before ingestion, Alka-Seltzer tablets use the action of effervescence to produce the release of carbon dioxide gas.1 This release of gas allows for the fizz to occur, and for excess sodium bicarbonate to aid in the pain relief, in combination with aspirin in the tablets.1,2 But, this need for pain relief from over-the-counter drugs has been monitored due to the
After we did the measurements, we found that an old penny weighs about 2.50g while a new penny weighs about 3.09g. Lastly, an empty vial weighs about 4.95g.
The pure product has a lower product yield than the crude. Since the pure product had to go through similar steps as the crude product, there could have been similar sources of errors as the crude. Also, the process of recrystallization removes impurities. Therefore, the impurities that were originally in the substance will be subtracted away from the original mass, only leaving the pure product. Lastly, during the process of weighing the final pure product, the filter paper was not involved in the measurement, unlike the crude product. After the filtration,
This is due to the fact that water moves from areas of low solute concentration to the areas of high solute concentration. If the solution has a high molarity of sucrose, that means water outside would move into the bag causing the mass of the bag to become greater. That is what happened in the experiment. The water moved in the bags that had a high molarity of sucrose and increased the mass of the the bags; this caused the the mass difference to be greater, which caused the percent change in mass be greater. Solution B had the greatest class average percent change in mass of 29.62% and the greatest molarity of 1.0M. Solution C had the smallest class average percent change in mass of 2.39% and the lowest molarity of 0.0M. There were a couple of errors that may have occurred in the duration of the experiment.
Excess Moisture: If some excess moisture was trapped under the foil and did not have a chance to properly evaporate. This would result in an alteration in the mass, which would then impact the mean molar mass.
1. Step six in the procedure is necessary because there maybe some left over solution left over in the filter and so we use the water to get rid of that excess solution which is leftover. Step six is also important because this 5 mL of water could make the left over precipitate release excess water in it making it so that the drying process is quicker.
I then measured out 100ml of soil and then I poured beaker number one through the funnel and let it filter down into beaker number five. I repeated the process with beakers two through four pouring them into beakers six through eight. When completed I let the filtration complete before making my observation. Here are my results.