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. Examples of impurities are competing side reactions, the incomplete removal of water from the sample, and aging chemicals which are not stored properly (Helmenstine, 2018). A limiting reagent, however, is the reactant completely …show more content…
Materials The amount of copper that was obtained was not the same as the mass expected, as it was significantly greater. This may be caused by side reactions, or if the elements that were used were not truly pure. These may be some reasons that caused the amount of copper to be greater, as the mass calculated should generally be close to, or less than the mass expected in pure reactions. The color of the solution was tinted green after this reaction was complete. This suggests that the reaction had some impurities with copper ions. Since the color of aluminum sulfate should be ideally clear, it is easily assumable that some copper ions dissolved into the solution. This is as Cu+ ions are green in aqueous solutions (Helmenstine, 2018). Therefore, the copper ions did not completely filter, creating a tinted green colored solution. Percent yield = (mass of actual yield )/(mass of theorethical yield) ×100% ≐(1.22 grams)/(0.7066 grams) × 100% ≐
The purpose of the lab is to acquire the percent composition of zinc and copper. The procedure included obtaining a post 1983 penny and washing it with soap and water. Using a triangular file, we made an X on the penny. Then, we cleaned the top and bottom of the penny with steel wool until it was shiny. We rinsed the penny in acetone and dried it with paper towel.
Then the mass of the copper metal and the percentage of Cu were obtained and compared throughout different groups and a mean and standard deviation was calculated for the
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
Calculate the mass of the isolated alum from the initial mass of the beaker and the mass with the sample. 2. Determine the theoretical yield of the alum in each trial. Use the aluminum foil as the limiting reagent and presume that the foil was pure aluminum. 3.
After a while, a brownish color substance started to form on the three iron nails. We predicted that the brown substance on the nails is copper because the reaction of copper(II) chloride with iron is a single displacement reaction, so copper would be produced. 0.48 grams of iron was used in the reaction because 2.73 grams subtracted by 2.25 grams is 0.48 grams. The 0.48 grams of iron had to be used in the reaction with copper(II) chloride in order to produce copper, according to the reaction equation: CuCl2+FeFeCl2+Cu. 0.52 grams of copper was produced after pouring out the copper(II) chloride solution and the three iron
We conducted our investigation this way because we wanted to easily find a way to prove that no mass can be created or destroyed in a reaction. The data we collected was the mass of the cup which
In this reaction NaOH was added to the Cu(NO3)2. The solution developed a precipitate which made the clear solution become cloudy and uniform in color (blue). The physical color change was demonstrated through the formation of the precipitate. The third step was the formation of CuO. In this reaction, the Cu(OH)2 product was heated on a hot plate and stirred continuously until the solution became colorless and a dark precipitate formed.
1. If you began with .5296 g of copper mesh and recovered .2937 g of elemental copper, what would be the percent recovery of the copper metal? 55.45% 2. Describe the difference in the appearance of the copper mesh vs. the appearance of the elemental copper at the end of the reaction sequence.
These color changes indicate a chemical change, which show that a reaction had occurred. In the first step when o-vanillin and p-toludine, imine was formed. The color change from green to orange suggests that imine appears as orange colored. In the second step, the addition of sodium borohydride reduced the imine into another derivative, which was yellowish lime color. The solution turned clear when acids and anhydrides was added, which indicated the precipitate were dissolved.
+ H2O (g) Reaction 4: when a sulphuric acid is added to the solution that contains copper (II) oxide, a double displacement reaction will occur. the copper (II) oxide will react with the sulphuric acid producing copper (II) sulfate and water. The copper and hydrogen gas replace each other. Balanced Chemical Equation: CuO (s) + H2SO4 (aq) —> CuSO4 (aq) + H2O (l) Reaction 5: when zinc is added to the copper (II) sulfate solution, a single displacement reaction will occur.
The other time where mass could have been lost was during reaction 3, more specifically each time the liquid was decanted. Although a few black sand-coffee grains of the copper (II) oxide lost do not seem like a significant amount, they do have an impact on the final result, and each time a few of the grains were accidentally decanted could have an impact on why our final recovered mass was less than the initial amount that we began
The final product weight for percent yield was only the solid E product, which missed one half of the final product produce. If both products were weight, the percent yield would have been larger that it was. Instead of 22.33%, it could have been 44.66%. To prove that both products were obtained, but only one of the two products was analyze, a TLC plate of the DCM layer, that contains both products, and of the final product, was obtain.
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.
The % yield was greater than 100% because the actual yield was greater than the theoretical yield. One error that may have caused this result to occur was that the copper may have not completely dried over the time it was left. If water was still inside the copper, it would increase the mass of the actual yield. If the copper was left in the beaker to dry for a longer time, it would help decrease the mass of the copper (as the water would be completely dried out) and bring the actual yield down.
Copper is mainly used due to its better resistance in corrosion than other metals and its unwillingly nonreaction with most strong acids. To investigate and identify the nature of the reactions of copper, one can synthesize copper into a series of chemical reactions and explore its physical and chemical properties. The pure substance undergoing the chemical reaction, in this instant copper, takes on different chemical reactions. There are four types of chemical reactions: combination or synthesis reactions, decomposition reactions, substitution or single replacement