Percent Yield Experiment

Secondly, the test tubes were not cleaned out. If there was residue from other chemicals on the test tube there could be an error in the reaction. Cleaning out the test tube before starting lab could prevent this. Finally, residue on gloves could have got into the solution. This could have caused an error in the reaction.

(2-3 sentences) First, percent yield cannot be over 100% because mass cannot be created; the collected mass of a substance can never go over the theoretical yield of that substance. Percent yield is also very rarely 100% because no equilibrium reaction, which is the type of reaction studied in this lab, can go to completion. There is always some amount of products that transforms back into reactants; therefore, theoretical yield, which assumes that the reaction goes to completion, will rarely equal experimental yield. 3.

The topic of this lab experiment is the relationship between percent yields and limiting reagents, and how it relates to copper (II) sulfate and aluminum foil. The objective was to determine the limiting reagent in a reaction and calculate the percent yield. To understand this, fundamental concepts of percent yields and limiting reagents are essential. A percent yield is defined as the ratio of the actual yield, to the theoretical yield in a reaction, expressed as a percent (Haberer, Salciccioli, & Sanader, 2011). This is useful as several impurities in this reaction possibly contributed to the percent yield.

This low percent recovery is because some of the solutions spilled onto the table, losing a lot of the precipitate. The recovered ethyl-4-aminobenzoate’s boiling point was within the accepted range of 85C; meaning, the amount recovered was pure. The % recovery for the benzoic acid was 5.33%. This low percent recovery could be due to the fact that instead of adding NaCl to increase the precipitate amount, the salting out effect, more of the HCl was used. This caused the precipitate amount to increase slightly but not as much as it could’ve if the salting out effect was used.

The purpose of this lab was to determine the percent water in magnesium sulfate heptahydrate, or Epsom salt. The experimental percent water is determined to be 42.06% in both trials, making the average also 42.06%. To determine this percent water a heating and cooling procedure was used. First, the vials were cleaned of impurities using the lab oven and were not touched after this point.

As seen in table 1, the theoretical yield was .712 g of C_17 H_19 NO_3. The % yield of this experiment was 7.51 % of C_17 H_19 NO_3. . This low yield can be explained from a poor recrystallization technique combined with potential contamination. Throughout the experiment, the mixture changed color from green, orange, to yellowish lime, and eventually clear.

In order to find the percent recovered, the mass of the copper had to be measured. The main purpose of doing this experiment was to find out the percent

=O groups present in the final product. This showed that my final product was not very pure and that there was a lot of contamination in the second part of the

The percent recovery was measured by dividing the amount from the second extraction on the total amount extracted multiple by 100. By using extraction solvent of 100 % methanol, the percent recovery was between 1-5 %, with mean value 3.72 %. That is considered slightly higher percentage when compared with the reported from Esteve et al. With increasing the dilution of Methanol, a slight increase reported in the percent recovery mean value between 12.17 – 16.33 %. PBS solution can be used for extraction of cocaine, although it has very high recovery percent of an average of 20.91%.

The data used in this experiment is the average of all the plants height, and does not count the length of the roots. This is because the averages will provide a more even set of data because not all plants are exactly the same and due to genetic variation some may grow higher or shorter than others. The data being analysed is the height it grew from when the hormones was placed on the plant (day 4), this is to ensure that if a plant grew taller or shorter than the others from day 0 till day 4 it would still be accurate when comparing to the other tests. Primary Data: In this experiment the average growth ranges from 0.7cm to 10.2cm in six days from when the hormones were placed on the plants for dicots, and 5.9cm to 10.4cm from when the hormones were placed on the plants for monocots.

Thus, using the theoretical yield (Equation 3) and the weights of crude and pure product discovered, the percent yield of crude product (Equation 4), the percent yield of pure product (Equation 5), as well as the percent recovery (Equation 6) were determined. Moles of the Reactants: Moles of bromobenzene = weight of bromobenzene (g)molecular weight (g/mol) = 1.218 g157.01 g/mol = 0.0078 mol Moles of magnesium = weight of magnesium (g)molecular weight (g/mol) = 0.153 g24.3 g/mol = 0.0063

If only one reactant is increased, then the chemical reaction will only produce a certain amount of products after the limiting reagent is used up, and in this experiment, the most mass the reaction could produce was 0.4 grams. Although we kept adding calcium chloride, not adding sodium hydroxide in the same proportions will not yield more product, which is the main goal in conducting this lab. We should have seen a plateau at 0.4 grams to show that the limiting reagent inhibited further Ca(OH)2 production, but we made several mistakes in our experiment, which made the data unusable to conclude. Once again, the data is polluted, so these number are not accurate, but it is the data our group has to work with. The theoretical yield should have been more than the actual yield, and the percentages should have been less than 100.

Pre- lab preparation To perform this investigation, a number of the solutions were needed to be prepared in advance. The following is the preparation process - Preparing the stock solution-The stock solution of Salicylic acid needed to be prepared well in advance before the experiment began. To do so, 1.73g of Salicylic Acid was weighed using the weighing balance. After Salicylic acid was weighed, it was transferred to a standard flask of 100cm3 and, 100cm3 of pure Ethanol (C2H5OH), was poured into the standard flask that contained the Salicylic acid.

The melting point range for the crude product was 113-115.3℃. the melting point range for the purified product was also 113-116℃. This melting point range was almost perfect to that of the theoretical melting point which is 113-115℃ proving that the product was in fact created. When looking at the percent yield of the crude acetanilide, there was an 81% yield which was a very good yield because the average percent yield is between 80-90%. The percent recovery of the acetanilide was 88% which is also very good because much of the product was recovered meaning that the product was in fact

AIM: The experiment is to investigate the effect of the change in the concentration of Hydrogen peroxide and sodium thiosulphate on the rate of reaction between potassium iodide (KI), hydrogen peroxide, Sodium thiosulfate (Na2S2O4) under acidic condition. Introduction: The rate of reaction can be defined as the rate at which the reactants are consumed of the rate at which product is formed.