PURPOSE The purpose of this experiment is to conduct a single displacement reaction using a reactant with impurities to deduce its effects on the actual yield of the precipitate by calculating percentage yield. INTRODUCTION In chemical reactions, there are limiting reagents which control the maximum yield of products. On the other hand, excess reactants are other reactants in a reaction that are left over or remain after the limiting reagent has been completely consumed. The maximum amount of product that any reaction can produce is called theoretical yield. To calculate theoretical yield, one must first write out a balanced chemical equation for the reaction to determine the number of moles of reactants used or products produced, in the reaction …show more content…
With the data collected from this chemical reaction percentage yield of the precipitate can be calculated to determine the effects of impurities in the reactants on percentage yield. PRE-LAB QUESTIONS 1. What is the balanced chemical equation for the reaction in this investigation? 2. Which reactant is considered impure in this investigation? The reactant that is considered impure in this investigation is the steel wool as it also contains carbon thus, it is not pure iron. 3. How might an impure reactant affect the percentage yield of a reaction? Explain. An impure reactant might decrease the percentage yield because impure substances contain less atoms of an element per mole than a pure substance. Consequently, there are less reactants in the reaction than what is expected. This causes the actual yield to be less than the theoretical yield so, an impure reactant should decrease the percentage yield of a reaction. 4. Why is it important to flush your skin with plenty of water if it comes in contact with copper (II) chloride dihydrate or hydrochloric
The last goal was to determine the percent yield of a product formed during a reaction with the unknown compound. Experimental Design The first day of lab consisted of various preliminary tests that helped identify the unknown compound.
So if 0.38 is divided by 0.49 and multiplied by 100 then the percent yield for Zinc Sulfide would be 77.6%. When it comes to Sodium Chloride, the theoretical yield is 0.58 grams and the actual yield is 0.45 grams. So when 0.45 grams is divided by 0.58 grams and multiplied by 100, the percent yield would be 77.5% of Sodium chloride. The actual yield is directly taken from the mass of the products in the experiment while the theoretical yield is determined by using stoichiometric calculations. To determine the theoretical yield, the reactants should be converted from grams to moles based on the coefficients in the chemical equation and the moles should be incorporated into the mass of the reactants.
This report presents how to optimize experiment and equipment to obtain highest percent yield possible. Percent yield is the percent ratio of actual yield to the theoretical yield. % yield= (Actual yield)/(Theoretical yield)×100% Where the actual yield is the amount of product actually produced in a chemical reaction in grams, theoretical yield is the amount of product obtained from the stoichiometry or balanced equation using the limiting reactant to determine the product. Units for both actual and theoretical yield need to be the same (moles of grams) (”Percent Yield Definition and Formula”, 2018).
Introduction: The purpose of this experiment is to demonstrate the different types of chemical reactions, those including Copper. There are different types of chemical reactions. A double displacement reaction is a chemical process involving the exchange of bonds between two reacting chemical species. A a decomposition reaction is the separation of a chemical compound into elements or simpler compounds and the single-displacement reaction is a type of
3. In this experiment, the percent yield was 90%. This number implies that there was little error in this experiment. However, this result could have been caused by certain external factors.
The experiment produced low results. The negative error was assumed to be caused by an error in the calibrating of the scale. During this lab the scale was not properly calibrated, therefore the data recorded and calculated using the mass values obtained by the scale was mistaken. This error could lead to the incorrect mass of the precipitate, the crucible and any other mass weight during the lab, which in turn derailed all the calculations. Another reason the results could be lower than the real value was so yield of precipitate occurs when soluble CIO3- was formed as the Cl- ions were lost through the filtration apparatus when the degeneration of the silver chloride occurs, with extra Ag+.
In this lab, one piece of evidence that showed a double displacement reaction occurred was when a solid (precipitate) was formed. This is evident in the reaction between sodium sulphate and barium chloride. One of the products in this reaction was barium sulphate which is a white precipitate in an aqueous solution. This precipitate is definite evidence of a chemical reaction. Another characteristic that showed a double displacement reaction occurred was when a gas was produced.
(NH4)2CO3 was added to the solution. Then the tube was placed into warm water. Once the tube was cooled, the tube was centrifuged and 0.5 mL of 6M acetic acid was added to the precipitate. This was done to see if the precipitate turned cloudy. The solution was clear and not cloudy.
The equation must be balanced in order to get the correct amount of the elements in the reaction to find out what is limiting or excess. The stoichiometry quiz 1 we took in class shows that you have to first balance the equation, find the limiting and excess reactants, then find the percent yield. When balancing an equation one has to follow the law of conservation of mass. So however much the equation starts out with is how much the equation needs to end with. “The law of conservation of matter states that matter can be neither created nor destroyed.”
Ideally, every mole of each reagent would be used up, and theoretical yield, we are assuming that every last mole of the reactants would
When water and vinegar were added to Powder A, the powder dissolved. This evidence shows that Powder A was soluble with vinegar and water. When iodine was added to Powder A, it reacted, changing color to orange/brown. Reactivity is a chemical property, it is the rate at which a substance inclines to undergo a chemical reaction. Powder B, when mixed with water, vinegar, and iodine, reacted by fizzing.
During this time observations on the precipitants were recorded. A sample of each beaker was pipetted from the top of the beaker without disturbing the precipitant and collected in sample bottles. The pH of the beaker solutions was measured using a laboratory table top pH meter. The samples of each beaker were tested later by lab TA and the concentration of Cu in each sample were measured as well as the concentration of Cu in the
The results of the experiment had fluctuated based on the temperature of the solution. In reference to Table 1 and Table 2, the results was evident enough to identify the patterns and the trends when it came to using the temperature as an independent variable. The results predicted a trend that the higher the temperature, the higher the rate of reaction is. Whereas, the lower the temperature slowed down the rate of reaction.
Objective: The purpose of this experiment was to gain a better understanding of what a chemical reaction is, how to identify if one actually occurred and correctly show one using a balanced chemical equation. Students will achieve this by mixing substances and attempting to determine whether a reaction took place using prior knowledge of indicators that determine the presence of a chemical reaction. Materials: Safety goggles Aluminum foil Beaker 50 mL of distilled water Copper (II) Chloride (CuCl2)